Report supporting Appropriate Assessment of Aquaculture and Risk … · 2019-07-26 · Directive....

Report supporting Appropriate Assessment of Aquaculture and Risk

Assessment of Fisheries in Clew Bay Complex SAC

(Site Code: 1482)

Marine Institute

Rinville, Oranmore

Co. Galway

19 July 2019

Contents

1 Preface ..................................................................................................................................... 1

2 Executive summary ................................................................................................................. 2

2.1 The SAC .............................................................................................................................. 2

2.2 Activities in the SAC ........................................................................................................... 2

2.3 The appropriate assessment and risk assessment process .................................................. 2

2.4 Data supports .................................................................................................................... 3

2.5 Findings ............................................................................................................................. 3

3 Introduction .............................................................................................................................. 5

4 Conservation Objectives for Clew Bay SAC (001482)......................................................... 5

4.1 The SAC extent ................................................................................................................... 5

4.2 Qualifying interests (SAC) ................................................................................................... 6

4.3 Conservation objectives for Clew Bay SAC .......................................................................... 8

4.4 Screening of Adjacent SACs or for ex situ effects .............................................................. 12

5 Details of the proposed plans and projects ......................................................................... 17

5.1 Aquaculture ..................................................................................................................... 17

5.1.1 Oyster Culture ........................................................................................................ 17

5.1.2 Subtidal Oyster culture .......................................................................................... 19

5.1.3 Rope Mussels ........................................................................................................ 19

5.1.4 Salmon Culture ...................................................................................................... 20

5.1.5 Scallop .................................................................................................................... 21

5.1.6 Clew Bay Seaweed Cultivation ............................................................................. 21

5.1.7 Clams ...................................................................................................................... 22

5.1.8 Abalone ................................................................................................................... 22

5.1.9 Lobster .................................................................................................................... 23

5.1.10 Hatchery Operations .............................................................................................. 23

5.1.11 Clew Bay CLAMS .................................................................................................. 23

5.2 Fishing activities ............................................................................................................... 26

5.2.1 The fleet .................................................................................................................. 26

5.2.2 Potting for shrimp ................................................................................................... 27

5.2.3 Potting for prawns .................................................................................................. 27

5.2.4 Potting for crab and lobster ................................................................................... 28

5.2.5 Potting for whelk .................................................................................................... 28

5.2.6 Tangle netting for crayfish ..................................................................................... 28

5.2.7 Gill netting for Pollack and other netting .............................................................. 29

5.2.8 Dredging for scallop ............................................................................................... 30

5.2.9 Dredging for oyster ................................................................................................ 31

5.2.10 Bottom trawling for mixed demersal fish .............................................................. 31

5.2.11 Mid-water trawling for pelagic fish ........................................................................ 32

5.2.12 Hook and line fishing for mackerel and Pollack .................................................. 32

5.2.13 Draft net fishing for salmon ................................................................................... 33

5.2.14 Trammel net fishing for bait .................................................................................. 33

5.2.15 Hand gathering of periwinkle and cockle ............................................................. 33

6 Natura Impact Statement for the proposed activities ......................................................... 35

6.1 Aquaculture ..................................................................................................................... 35

6.2 Fisheries ........................................................................................................................... 42

7 Screening of Aquaculture Activities ..................................................................................... 51

7.1 Aquaculture Activity Screening ......................................................................................... 51

8 Assessment of Aquaculture Activities ................................................................................. 56

8.1 Determining significance .................................................................................................. 56

8.2 Sensitivity and Assessment Rationale ............................................................................... 57

8.3 Assessment of the effects of aquaculture production on the Conservation Objectives for

habitat features in Clew Bay Complex SAC. .................................................................................. 59

8.4 Assessment of the effects of shellfish production on the Conservation Objectives for

Harbour Seal in Clew Bay Complex SAC. ....................................................................................... 67

8.5 Assessment of the effects of shellfish production on the Conservation Objectives for otter

and migrating salmon in Clew Bay Complex SAC. ......................................................................... 70

9 Risk Assessment of Fishing Activities ................................................................................. 73

9.1 Risk assessment screening of fisheries ............................................................................. 73

9.2 Methodology: .................................................................................................................. 73

9.2.1 Determining risk to the conservation objectives .................................................. 73

9.2.2 Sensitivity of characterizing species and marine communities to physical

disturbance by fishing gears ................................................................................................ 76

9.3 Risk assessment of impact of fishing gears on marine benthic communities ..................... 77

9.3.1 Potting for shrimp ................................................................................................... 78

9.3.2 Potting for prawns .................................................................................................. 78

9.3.3 Potting for crab and lobster ................................................................................... 79

9.3.4 Potting for whelk .................................................................................................... 79

9.3.5 Tangle netting for crayfish ..................................................................................... 79

9.3.6 Gill netting for Pollack and mackerel .................................................................... 80

9.3.7 Dredging for scallop ............................................................................................... 80

9.3.8 Dredging for oyster ................................................................................................ 81

9.3.9 Bottom trawling for mixed demersal fish .............................................................. 82

9.3.10 Midwater trawling for pelagic fish ......................................................................... 82

9.3.11 Hook and line fishing for mackerel ....................................................................... 82

9.3.12 Draft net fishing for salmon ................................................................................... 82

9.3.13 Trammel net fishing for bait .................................................................................. 82

9.3.14 Hand gathering of periwinkle and cockle ............................................................. 83

9.3.15 Cumulative effects of fishing on marine communities ........................................ 83

9.4 Risk assessment of impact of fishing gears on designated species harbour seal, otter and

salmon 90

9.4.1 Conservation objectives, status and habitat use ................................................. 90

9.4.2 Risk of capture ....................................................................................................... 91

9.4.3 Risk of prey depletion ............................................................................................ 93

9.4.4 Otter ........................................................................................................................ 93

9.4.5 Risk of disturbance ................................................................................................ 93

9.4.6 Cumulative effects of fishing on designated species .......................................... 94

9.5 Fisheries risk profile ......................................................................................................... 95

9.5.1 Marine Community types ...................................................................................... 95

9.5.2 Species ................................................................................................................... 96

10 In-combination effects of aquaculture, fisheries and other activities ............................ 96

11 SAC Aquaculture Appropriate Assessment Concluding Statement and

Recommendations ........................................................................................................................ 98

11.1 Habitats ........................................................................................................................... 98

11.2 Species ............................................................................................................................. 99

12 SAC Fisheries Risk Assessment Concluding Statement and Recommendations ...... 99

12.1 Habitats ........................................................................................................................... 99

12.2 Species ........................................................................................................................... 100

13 References....................................................................................................................... 101

List of Figures

Figure 1. The extent of Clew Bay Complex SAC (site code 001482). .................................................... 6

Figure 2. Principal benthic communities recorded within the qualifying interests Large shallow inlets and

bays and Mudflats and sandflats not covered by seawater at low tide within Clew Bay Complex SAC

(Site Code 001482) (NPWS 2011). ......................................................................................................... 7

Figure 3. Harbour Seal (Phoca vitulina) locations in Clew Bay Complex SAC. ...................................... 8

Figure 4. Natura 2000 sites adjacent to the Clew Bay Complex SAC .................................................. 12

Figure 5: Aquaculture sites (Licenced and Applications) and access routes in Clew Bay Complex SAC

(access routes not drawn to scale) ....................................................................................................... 24

Figure 6: Distribution of shrimp fishing, derived from expert data, in relation to Clew Bay SAC ......... 27

Figure 7: Distribution of fishing for lobster, crab and prawns in relation to the Clew Bay SAC ........... 28

Figure 8: Distribution of tangle netting for crayfish in relation to the Clew Bay SAC ............................ 29

Figure 9: Distribution of Pollack and mackerel gill netting and trolling in relation to the Clew Bay SAC

.............................................................................................................................................................. 30

Figure 10: Distribution of scallop fishing, derived from survey data and expert data, in relation to Clew

Bay SAC ................................................................................................................................................ 30

Figure 11: Distribution of oyster fishing, derived from survey data, in relation to Clew Bay SAC ....... 31

Figure 12: Distribution of bottom trawl fishing, derived from VMS data (vessels >15m) and expert data,

in relation to Clew Bay SAC .................................................................................................................. 32

Figure 13: Distribution of mid-water trawling as shown by VMS data (vessels>15m). ........................ 32

Figure 14 Distribution of trammel netting for bait in relation to the Clew Bay SAC. ............................. 33

Figure 15: Distribution of cockle stocks, derived from survey data, in Clew Bay SAC ......................... 34

Figure 16: Determination of significant effects on community distribution, structure and function for

sedimentary habitats (following NPWS 2011b)..................................................................................... 57

Figure 17. Harbour Seal Sites and Aquaculture Sites (licenced and applications) in Clew Bay – North

.............................................................................................................................................................. 69

Figure 18. Harbour Seal Sites and Aquaculture Sites (licenced and applications) in Clew Bay – South

.............................................................................................................................................................. 69

Figure 19. The distribution of fishing activity (count = number of fishing metier) in relation to Laminaria

reef communities in Clew Bay SAC. ..................................................................................................... 84

Figure 20. The distribution of fishing activity (count = number of fishing metier) in relation to faunal reef

communities in Clew Bay SAC ............................................................................................................. 85

Figure 21. The distribution of fishing activity (count = number of fishing metier) in relation to Zostera


Figure 22. The distribution of fishing activity (count = number of fishing metier) in relation to Maerl


List of Tables

Table 1. Conservation objectives and targets for marine habitats and species in Clew Bay SAC

(0001482) (NPWS 2012; NPWS 2011). Annex I and II features listed in bold. ...................................... 9

Table 2 Natura Sites adjacent to Clew Bay Complex SAC and qualifying features with initial screening

assessment on likely interactions with fisheries and aquaculture activities. ......................................... 13

Table 3: Spatial extent (ha) of aquaculture activities overlapping with the qualifying interest (1140 -

Mudflats and sandflats not covered by seawater at low tide and 1160-Large shallow inlets and bays) in

Clew Bay Complex SAC, presented according to culture species, method of cultivation and license

status. .................................................................................................................................................... 25

Table 4: The inshore fishing fleet in Clew Bay ...................................................................................... 26

Table 5: Potential indicative environmental pressures of aquaculture activities within the qualifying

interests (Mudflats and sandflats not covered by seawater at low tide (1140) and Large Shallow Inlets

and Bays (1160)) of Clew Bay Complex SAC....................................................................................... 43

Table 6: Potential interactions between aquaculture activities and the Annex II species Harbour Seal

(Phoca vitulina) within the Clew Bay SAC. ........................................................................................... 50

Table 7: Habitat utilisation i.e. spatial overlap in hectares and percentage (given in parentheses) of

Aquaculture activity over community types within the qualifying interest 1140 - Mudflat and sandflats

not covered by seawater at low tide of Clew Bay Complex SAC. (Spatial data based on licence database

provided by DAFM. Habitat data provided in NPWS 2011 – supporting docs marine and coastal) ..... 53

Table 8: Habitat utilisation i.e. spatial overlap in hectares and percentage (given in parentheses) by

Aquaculture activity over specific community types within the qualifying interest 1160 – Large shallow

inlets and bays of Clew Bay Complex SAC based on licence database provided by DAFM. Habitat data

provided in NPWS 2011 – supporting docs marine and coastal) ......................................................... 54

Table 9: Matrix showing the characterising habitats sensitivity scores x pressure categories for habitats

in Clew Bay Complex SAC (ABPMer 2013a-h). ................................................................................... 61

Table 10: Matrix showing the characterising species sensitivity scores x pressure categories for habitats

in Clew Bay Complex SAC (ABPMer 2013a-h). Table 11 provides the code for the various

categorisation of sensitivity and confidence .......................................................................................... 62

Table 11: Codes of sensitivity and confidence applying to species and pressure interactions presented

in Tables 10 and 11. .............................................................................................................................. 63

Table 12. Interactions between the relevant aquaculture activities and the habitat feature 1140

constituent communities with a broad conclusion on the nature of the interactions ............................. 64

Table 13. Interactions between the relevant aquaculture activities and the habitat feature 1160

constituent communities with a broad conclusion on the nature of the interactions. ............................ 65

Table 14. Risk categorization for fisheries and designated habitat interactions (see: Marine Institute

2013). Colours indicate risk category. Disturbance is defined as that which leads to a change in

characterising species. Such disturbance may be temporary or persistent depending on the frequency

of impact and the sensitivity of the receiving environment. Colours indicate the probable need for

mitigation of effects from green (no mitigation needed), to yellow (mitigation unlikely to be needed but

review on a case by case basis), orange (mitigation probably needed) and red (mitigation required) 74

Table 15. Risk categorization for fisheries and designated species interactions (Marine Institute 2013)

.............................................................................................................................................................. 75

Table 16. Percentage (%) overlap of fisheries with seabed habitats and qualifying interests 1140 and

1160. ..................................................................................................................................................... 87

Table 17. Percentage overlap of fishing metiers, which have significant contact with the seabed, with

marine community types in Habitats 1140 and 1160 in Clew Bay. MCTs with shading have no fishery

overlapping with them ........................................................................................................................... 88

Table 18. The categorical risk (= consequence*likelihood of consequence) posed by bottom contacting

gears each fishing activity to marine communities. Blank cells indicate no spatial overlap or occurrence

of the fishery in the MCT. Colour codes indicate the probable need for mitigation as described in Tables

15 and 16 (See section 9.2.1). .............................................................................................................. 89

Table 19. Risk (consequence*likelihood of consequence) of by-catch, prey depletion and disturbance

by fisheries to designated species in Clew Bay .................................................................................... 95

1

1 Preface

In Ireland, the implementation of Article 6 of the Habitats Directive in relation to aquaculture and fishing

projects and plans that occur within designated sites is achieved through sub-Article 6(3) of the

Directive. Fisheries not coming under the scope of Article 6.3, i.e. those fisheries not subject to

secondary licencing, are subject to risk assessment. Identified risks to designated features can then be

mitigated and deterioration of such features can be avoided as envisaged by sub-article 6.2.

Fisheries, other than oyster fisheries, and aquaculture activities are licenced by the Department of

Agriculture, Food and Marine (DAFM). Oyster fisheries are licenced by the Department of

Communications Energy and natural Resources (DCENR). The Habitats Directive is transposed in

Ireland in the European Communities (Birds and Natural Habitats) Regulations 2011 (S.I. 477 of 2011).

Appropriate assessments (AA) and risk assessments (RA) of fishing activities are carried out against

the conservation objectives (COs), and more specifically on the version of the COs that are available

at the time of the Assessment, for designated ecological features, within the site, as defined by the

National Parks and Wildlife Service (NPWS). NPWS are the competent authority for the management

of Natura 2000 sites in Ireland. Obviously, aquaculture and fishing operations existed in coastal areas

prior to the designation of such areas under the Directives. Ireland is thereby assessing both existing

and proposed aquaculture and fishing activities in such sites. This is an incremental process, as agreed

with the EU Commission in 2009, and will eventually cover all fishing and aquaculture activities in all

Natura 2000 sites.

The process of identifying existing and proposed activities and submitting these for assessment is, in

the case of fisheries projects and plans, outlined in S.I. 290 of 2013. Fisheries projects or plans are

taken to mean those fisheries that are subject to annual secondary licencing or authorization. Here, the

industry or the Minister may bring forward fishing proposals or plans which become subject to

assessment. These so called Fishery Natura Plans (FNPs) may simply be descriptions of existing

activities or may also include modifications to activities that mitigate, prior to the assessment, perceived

effects to the ecology of a designated feature in the site. In the case of other fisheries, that are not

projects or plans, data on activity are collated and subject to a risk assessment against the COs. Oyster

fisheries, managed by Department of Communications, Climate Action and Environment (DCCAE), do

not come under the remit of S.I. 290 of 2013 but are defined as projects or plans as they are authorized

annually and are therefore also subject to AA.

In the case of aquaculture, DAFM receives applications to undertake such activity and submits a set of

applications, at a defined point in time, for assessment. The FNPs and aquaculture applications are

then subject to AA. If the AA or the RA process finds that the possibility of significant effects cannot be

discounted or that there is a likelihood of negative consequence for designated features then such

activities will need to be mitigated further if they are to continue. The assessments are not explicit on

how this mitigation should be achieved but rather indicate whether mitigation is required or not and what

results should be achieved.

2

2 Executive summary

2.1 The SAC

Clew Bay is designated as a Special Area of Conservation (SAC) under the Habitats Directive. The

marine area is designated as a large shallow inlet and bay and for intertidal mud and sand flats not

covered by seawater at low tide. The bay supports a variety of sub-tidal and intertidal sedimentary and

reef habitats including habitats that are sensitive to pressures, which might arise from fishing and

aquaculture, such as maerl (corraline algae), seagrass and kelp reefs. The area is also designated for

and supports significant numbers of Harbour Seal and otter while salmon, designated in the Newport

River which flows into the north east corner of the Bay, migrate through the Bay as smolts and as mature

salmon returning from sea. Conservation Objectives for these habitats and species were identified by

NPWS (2011a) and relate to the requirement to maintain habitat distribution, structure and function, as

defined by characterizing (dominant) species in these habitats. For designated species the objective is

to maintain various attributes of the populations including population size, cohort structure and the

distribution of the species in the Bay. Guidance on the conservation objectives is provided by NPWS

(2011b).

2.2 Activities in the SAC

There is a diverse range of aquaculture and fishing and activities in the Bay.

There is an intensive autumn pot fishery for shrimp. Lobster and crab are fished throughout the year.

Crayfish and demersal fish are targeted with tangle nets and gill nets in the outer Bay and beyond.

Scallop are fished in the outer part of the SAC. Oysters are fished in discrete areas in the eastern part

of the SAC. Demersal and mid-water trawling occurs in the outer part of the Bay but not in the SAC.

Line fishing for mackerel and Pollack is common in summer.

The main aquaculture activity is oyster culture with lesser numbers of licences for suspended mussel

culture and finfish farming of salmon. Other species cultured included abalone and scallop. The Pacific

oyster (Crassostrea gigas) is typically cultured on trestles in intertidal areas. Some sites are licenced

for the culture of triploid oysters on the seabed.

2.3 The appropriate assessment and risk assessment process

The function of an appropriate assessment and risk assessment is to determine if the ongoing and

proposed aquaculture and fisheries activities are consistent with the Conservation Objectives for the

Natura site or if such activities will lead to deterioration in the attributes of the habitats and species over

time and in relation to the scale, frequency and intensity of the activities. NPWS (2011b) provide

guidance on interpretation of the Conservation Objectives which are, in effect, management targets for

habitats and species in the Bay. This guidance is scaled relative to the anticipated sensitivity of habitats

and species to disturbance by the proposed activities. Some activities are deemed to be wholly

inconsistent with long term maintenance of certain sensitive habitats while other habitats can tolerate a

range of activities. The appropriate assessment and risk assessment process is divided into a number

of stages consisting of a preliminary risk identification, and subsequent assessment (allied with

3

mitigation measures if necessary) which are covered in this report. The first stage of the AA process is

an initial screening wherein activities which cannot have, because they do not spatially overlap with a

given habitat or have a clear pathway for interaction, any impact on the conservation features and are

therefore excluded from further consideration. The next phase is the Natura Impact Statement (NIS)

where interactions (or risk of) are identified. Further to this, an assessment on the significance of the

likely interactions between activities and conservation features is conducted. Mitigation measures (if

necessary) will be introduced in situations where the risk of significant disturbance is identified. In

situations where there is no obvious mitigation to reduce the risk of significant impact, it is advised that

caution should be applied in licencing decisions. Overall the Appropriate Assessment is both the

process and the assessment undertaken by the competent authority to effectively validate this

Screening Report and/or NIS.It is important to note that the screening process is considered

conservative, in that other activities which may overlap with habitats but which may have very benign

effects are retained for full assessment. In the case or risk assessments consequence and likelihood of

the consequence occurring are scored categorically as separate components of risk. Risk scores are

used to indicate the requirement for mitigation.

2.4 Data supports

Distribution of habitats and species population data are provided by NPWS1. Fishing data are compiled

from various sources including survey data, questionnaire data and expert knowledge. Information on

Aquaculture licences and applications are provided by DAFM2. Aquaculture industry profiles were

provided by BIM. Scientific reports on the potential effects of various activities on habitats and species

have been compiled by the MI and provide the evidence base for the findings. The data supporting the

assessment of individual activities vary and provides for varying degrees of confidence in the findings.

2.5 Findings

The appropriate assessment for aquaculture finds that the aquaculture activities, at the current and

proposed or likely future scale and frequency of activity are consistent with the Conservation Objectives.

Specifically:

- Aquaculture and Habitats: Based upon the scale of spatial overlap and the relatively high tolerance

levels of the community types and species therein and given the likely interactions between current

and proposed aquaculture activities with these habitats, it is concluded that consideration can be

given to licencing (existing and applications) in the Annex 1 habitats – 1140 (Mudflats and sandflats

not covered by seawater at low tide) and 1160 (Large Shallow Inlets and Bays). The movement of

stock in and out of Clew Bay Complex SAC should adhere to relevant fish health legislation and

follow best practice guidelines.

1 NPWS Geodatabase Ver: September 2013 - http://www.npws.ie/mapsanddata/habitatspeciesdata/

2 DAFM Aquaculture Database version Aquaculture: 30th Aug 2013

4

- The presence of the carpet sea squirt in Clew Bay is noted. It is recommended that Methods should

be employed to ensure that structures and netting are kept clean at all times and that any biofouling

by alien invasive species be removed and disposed of in a responsible manner, such that it will not

pose a risk to the conservation features of the site.

- Aquaculture and species: It is acknowledged in this assessment that the favourable conservation

status of the Harbour seal (Phoca vitulina) has been achieved given current levels of aquaculture

production within the SAC. On this basis, the current levels of licenced aquaculture are considered

non-disturbing to harbour seal conservation features. It is anticipated that new applications will also

result in no disturbances. The aquaculture activities proposed do not pose a threat to otter and in the

Clew Bay Complex SAC.

- Assuming the management and regulatory systems that are in place are fully operational, the current

finfish aquaculture activities carried out do not pose a risk to salmon migrating through the Clew Bay

Complex SAC.

5

3 Introduction

This document assesses the potential ecological interactions of aquaculture and fisheries activities

within Clew Bay Complex SAC (site code 1428) on the Conservation Objectives (COs) of the site.

The information upon which this assessment is based is a list of applications and extant licences for

aquaculture activities administered by the Department of Agriculture Food and Marine (DAFM) and

forwarded to the Marine Institute as of August 2013; as well as aquaculture and fishery profiling

information provided on behalf of the operators by Bord Iascaigh Mara. The spatial extent of aquaculture

licences is derived from a database managed by the DAFM3 and shared with the Marine Institute.

4 Conservation Objectives for Clew Bay SAC (001482)

The appropriate assessment of aquaculture in relation to the Conservation Objectives for Clew Bay

Complex SAC is based on Version 1.0 of the objectives (NPWS 2011a - 19 July 2011) and supporting

documentation (NPWS 2011b - Version 1 June, 2011). The spatial data for conservation features was

provided by NPWS4.

4.1 The SAC extent

Clew Bay Complex SAC is a large SAC and comprises the majority of the inner part of Clew Bay

encompassing all of the islands located therein as well as the coastal lagoon, Lough Furnace. The site

is comprised of a wide range of intertidal and subtidal habitats, including mudflats and sandflats not

covered by seawater at low tide, large shallow inlets and bays as well as coastal lagoons. A number of

coastal habitats can also be found in the SAC, including Embryonic shifting dunes, shifting dunes along

the shoreline with Ammophilia arenaria (“white dunes”). The SAC is also considered an important site

for the two mammal species harbour seal (Phoca vitulina) and the otter (Lutra lutra). The extent of the

SAC is shown in Figure 1 below.

3 DAFM Aquaculture Database version Aquaculture: 30th Aug 2013 4 NPWS Geodatabase Ver: September 2013 - http://www.npws.ie/mapsanddata/habitatspeciesdata/

6

Figure 1. The extent of Clew Bay Complex SAC (site code 001482).

4.2 Qualifying interests (SAC)

The SAC is designated for the following habitats and species (NPWS 2011a), as listed in Annex I and

II of the Habitats Directive:

1013 Geyer's whorl snail Vertigo geyeri

1140 Mudflats and sandflats not covered by seawater at low tide

1150 Coastal lagoons

1160 Large shallow inlets and bays

1210 Annual vegetation of drift lines

1220 Perennial vegetation of stony banks

1330 Atlantic salt meadows (Glauco‐Puccinellietalia maritimae)

1355 Otter Lutra lutra

1365 Common (Harbour) seal Phoca vitulina

2110 Embryonic shifting dunes

2120 Shifting dunes along the shoreline with Ammophila arenaria ("white dunes")

Constituent communities and community complexes recorded within the qualifying interest Annex 1

habitats (i.e. 1140 - Mudflats and sandflats not covered by seawater at low tide and 1160 - Large

Shallow inlets and Bays) are listed in NPWS (2011b) and illustrated in Figure 2 and consist of:

Zostera dominated community

Maërl dominated communities

Sandy mud with polychaetes and bivalves community complex

Fine sand dominated by Nephtys cirrosa community

Shingle

7

Reef (Laminaria dominated community)

Intertidal sandy mud with Tubificoides benedii and Pygospio elegans community complex

Figure 2. Principal benthic communities recorded within the qualifying interests Large shallow

inlets and bays and Mudflats and sandflats not covered by seawater at low tide within Clew

Bay Complex SAC (Site Code 001482) (NPWS 2011).

The Clew Bay Complex SAC is designated for the Harbour seal (Phoca vitulina) and has been the

subject of monitoring of populations during the molting season (August-September) from 2009-2011 in

Westport Bay. Recent estimates of populations at the site range from 121 in 2009, 118 in 2010, and

116 in 2011 (NPWS 2010, 2011c, 2012a). Both 2010 and 2011 estimates were likely considered

underestimates based upon restricted visibility during surveying. A number of different locations have

been identified within the SAC and are considered important to the overall welfare and health of the

populations at the site. Figure 3 identifies these locations and distinguishes between breeding, moulting

and resting sites. A prioritisation based upon sensitive periods in the life cycle have been identified by

the competent authority, i.e. NPWS (NPWS 2011c). Important periods are the pupping season (May-

July) and molting season (August-September) and both periods and locations are considered important

periods to the overall health of the population in the SAC and that any disturbance during these times

should be kept to a minimum. Less information is known about resting period (October-April) and resting

areas throughout the SAC. The resting locations provided on Figure 3 are indicative only and the

sheltered areas within the entire SAC are considered suitable habitat for resting (NPWS 2011c).

8

Figure 3. Harbour Seal (Phoca vitulina) locations in Clew Bay Complex SAC.

4.3 Conservation objectives for Clew Bay SAC

The conservation objectives for the qualifying interests (SAC) were identified in NPWS (2011a). The

natural condition of the designated features should be preserved with respect to their area, distribution,

extent and community distribution. Habitat availability should be maintained for designated species and

human disturbance should not adversely affect such species. The features, objectives and targets of

each of the qualifying interests within the SAC are listed in Table 1 below.

9

Table 1. Conservation objectives and targets for marine habitats and species in Clew Bay SAC (0001482) (NPWS 2012; NPWS 2011). Annex I and II

features listed in bold.

FEATURE (COMMUNITY TYPE) OBJECTIVE TARGET

Geyer's whorl snail Vertigo geyeri The status of Geyer's whorl snail as a qualifying Annex II species for Clew Bay Complex SAC is currently

under review. The outcome of this review will determine whether a site‐specific conservation objective is set for this species.

Mudflats and sandflats not covered by seawater at low tide

Maintain favourable conservation condition 1277 ha; Permanent habitat is stable or increasing, subject to natural processes

(Intertidal sandy mud with Tubificoides benedii and Pygospio elegans community

complex) Maintain favourable conservation condition 788ha; Maintained in a natural condition

(Sandy mud with polychaetes and bivalves community complex)

Maintain favourable conservation condition 445ha; Maintained in a natural condition

(Fine sand dominated by Nephtys cirrosa community)

Maintain favourable conservation condition 44ha; Maintained in a natural condition

Large shallow inlets and Bays Maintain favourable conservation condition

10189ha;Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species.

(Zostera dominated communities) Maintain favourable conservation condition 142ha; Maintain natural extent and high quality of Zostera dominated communities

(Maerl dominated communities) Maintain favourable conservation condition 288ha; Maintain natural extent and high quality of Mearl

dominated communities

(Sandy mud with polychaetes and bivalves community complex)

Maintain favourable conservation condition 5,791ha; Maintained in a natural condition

(Fine sand dominated by Nephtys cirrosa community) Maintain favourable conservation condition 296ha; Maintained in a natural condition.

10


(Intertidal sandy mud with Tubificoides benedii and Pygospio elegans community

complex) Maintain favourable conservation condition 788ha; Maintained in a natural condition

(Shingle) Maintain favourable conservation condition 146ha; Maintained in a natural condition

(Reef) Maintain favourable conservation condition 2,687ha; Maintained in a natural condition

Coastal Lagoons Maintain favourable conservation condition

163.3ha; Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species.

Annual vegetation of drift lines Maintain favourable conservation condition


Perennial vegetation of stony banks Maintain favourable conservation condition


Atlantic salt meadows (Glauco‐Puccinellietalia maritimae)

Maintain favourable conservation condition

T38.86ha; Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species.

Otter Lutra lutra Restore favourable conservation conditions

Maintain distribution - 88% positive survey sites, 2426.7ha; No significant decline in extent of marine habitat; Couching sites and holts - no significant decline and minimise disturbance: Fish biomass - No significant decline in marine fish species in otter diet. Barriers to connectivity - No significant increase.

Harbour Seal Phoca vitulina Maintain favourable conservation condition

The range of use within the site should not be restricted by artificial barriers; all sites should be maintained in natural condition; human activities should occur at levels that do not adversely affect harbour seal population at the site.

11


Embryonic shifting dunes Restore favourable conservation condition

1.40ha; Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species

Shifting dunes along the shoreline with Ammophila arenaria ("white dunes")

Maintain favourable conservation condition

0.54ha;Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species

12

4.4 Screening of Adjacent SACs or for ex situ effects

In addition to the Clew Bay Complex SAC there are a number of other Natura 2000 sites proximate to

the proposed activities (Figure 4). The characteristic features of these sites are identified in Table 2

where a preliminary screening is carried out on the likely interaction with aquaculture and fishery

activities based primarily upon the likelihood of spatial overlap. In addition species migrating to and from

the site may be affected by activities, such as fisheries, operating outside the site (ex situ effects).

Qualifying features that do not screen out because of ex situ effects or because of effects on features

in adjacent SACs are carried forward for further assessment in Sections 8 and 9. These include Atlantic

Salmon, Otter and Harbour Seal.

Figure 4. Natura 2000 sites adjacent to the Clew Bay Complex SAC

.

13

Table 2 Natura Sites adjacent to Clew Bay Complex SAC and qualifying features with initial screening assessment on likely interactions with fisheries

and aquaculture activities.

NATURA SITE QUALIFYING FEATURES [HABITAT/SPECIES CODE] AQUACULTURE INITIAL SCREENING

Owenduff/Nephin Complex SAC

(000534) Salmon (Salmo salar) [1106]

Migrating salmon passing through Clew Bay Complex SAC and could interact with activities covered in this assessment- carry forward to Section 8.

Otter (Lutra lutra) [1355]

Potential for otter to link between this SAC and Clew Bay Complex SAC. Otter also a feature of Clew Bay Complex SAC - carry forward to Section 8.

Shining sickle moss (Drepanocladus vernicosus) [1393]

No spatial overlap or likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis

Marsh saxifrage (Saxifraga hirculus) [1528] No spatial overlap or likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis

Oligotrophic waters containing very few minerals of sandy plains (Littorelletalia uniflorae) [3110]


Oligotrophic to mesotrophic standing waters with vegetation of the Littorelletea uniflorae and/or of the Isoete-Nanojuncetea [3130]


Natural dystrophic lakes and ponds [3160] No spatial overlap or likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis

14


Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation [3260]


Northern Atlantic wet heaths with Erica tetralix [4010]


Alpine and Boreal heaths [4060] No spatial overlap or likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis

Juniperus communis formations on heaths or calcareous grasslands [5130]


Blanket bog (*active only) [7130] No spatial overlap or likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis

Transition mires and quaking bogs [7140] No spatial overlap or likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis

Owenduff/Nephin Complex SPA

(004098)

Merlin (Falco columbarius) (breeding) [A098]

No likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis

Golden plover (Pluvialis apricaria) (breeding) [A140]

No likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis

Greenland White fronted Goose (Anser albifrons flavirostris) (wintering) [A395]


15


Corraun Plateau SAC (000485) Oligotrophic waters containing very few minerals of sandy plains (Littorelletalia uniflorae) [3110]




European dry heaths [4030] No spatial overlap or likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis

Alpine and Boreal heaths [4060] No spatial overlap or likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis


Juniperus communis formations on heaths or calcareous grasslands [5130]


West Connaught Coast SAC (002998)

Bottlenose Dolphin (Tursiops truncates)

Structures do not pose a risk to dolphin either because of dolphin’s ability to avoid in subtidal areas and shallow nature of intertidal sites – excluded from further analysis

Newport River SAC (002144) Freshwater pearl mussel (Margaritifera margaritifera) [1029]


Salmon (Salmo salar) [1106] Migrating salmon passing through Clew Bay Complex SAC - carry forward to Section 8.

16





Oldhead Wood SAC (000532)

European dry heaths [4030] No spatial overlap or likely interaction with aquaculture in Clew Bay Complex SAC – excluded from further analysis

Old sessile oak woods with Ilex and Blechnum in British Isles [91A0]


17

5 Details of the proposed plans and projects

5.1 Aquaculture

Aquaculture in Clew Bay Complex SAC focuses primarily on shellfish species (oysters and mussels,)

with 5 locations dedicated to the culture of Atlantic Salmon (Figure 5). In addition, a single land-based

aquaculture licence (fish hatchery) is held adjacent to the Coastal Lagoon (Furnace Lough).

Descriptions of Spatial extents of existing and proposed activities within the qualifying interest (Mudflats

and sandflats not covered by seawater at low tide (1140) and large shallow inlets and bays (1160) of

Clew Bay Complex SAC were calculated using coordinates of activity areas in a GIS. The spatial extent

of the various aquaculture activities (current and proposed) overlapping the habitat features is

presented in Table 3 (data provided by DAFM). It must be noted that many of the applications for

shellfish culture in Clew Bay represent realignment or expansion of existing licenced sites. In effect, if

the applications are granted, then the existing licences would be surrendered; therefore, the total spatial

coverage of activities (sites) on habitat features presented on final row in Table 3 represents a

‘corrected’ total of the maximum level of proposed activity in the Clew Bay Complex SAC. In addition,

the access routes for those sites not accessed by boat are also provided in Figure 5. These routes are

typically single or double tracks that run along the most stable shore from the point of entry to the

aquaculture sites. Given the necessity for stability, the routes are not always the most direct. An

estimate of the spatial extent of access routes based upon a putative width of 10m and linear extent is

included in Table 3.

5.1.1 Oyster Culture

Currently there are 52 licenced sites for aquaculture in Clew Bay. These range from 1 each for scallop,

abalone and lobster, 5 for rope mussels, 33 for intensive intertidal culture of oysters, 5 for extensive on-

bottom culture of triploid oysters and 5 for salmon culture. There are currently 9 applications for the

culture of intertidal oysters and one for a realignment of a rope mussel culture site.

A single species forms the basis of oyster aquaculture operation in Clew Bay Complex SAC, i.e. the

Pacific oyster, Crassostrea gigas.. Pacific oysters have been grown successfully in Clew Bay since

completion of trials in 1984. They are grown intensively using the traditional bag and trestle method

within the intertidal zone. Trestles used in Clew Bay are both 5-bag and 6-bag trestles. They are made

from steel and measure between 3 and 4 metres in length, are approximately 1 metre in width and

stand between 0.5 and 0.7 metre in height. Oyster bags are made of a plastic (HDPE) mesh, and vary

in mesh size (4mm, 6mm, 9mm and 14 mm) depending on oyster stock grade. The bags are fastened

to the trestles with rubber straps and hooks. Trials took place in the 1990’s using cylindrical containers

and baskets called ‘Ortecs’ which hung from modified trestles.

The Pacific oyster is a bivalve mollusc that filter feed plankton and other organic matter from the sea

when submerged during high tide periods. All the Clew Bay pacific oysters farms are positioned

between mean Low Water Spring and mean Low Water Neap, allowing on average between 2 and 5

18

hours exposure depending on location, tidal and weather conditions. Maintenance activities on-site

include shaking and turning of bags, and hand removal of fouling and seaweed to ensure maintenance

of water flow through the bags when submerged.

The production cycle begins in Clew Bay when G4 to G8 (6 – 10 mm, respectively) oyster seed is

introduced from UK and French hatcheries. On rare occasions seed comes in at a smaller size of less

than 4 mm and are put into 2 and 3 mm plastic mesh pouches within 4mm oyster bags where they

remain for few months until they reach 6 mm and are ready to be transferred to the 4 mm oyster bag.

In the past Diploid oyster seed has also been sourced from 2 Irish hatcheries – Cartron Point Shellfish,

Co. Clare and Boet Mor Seafoods, Co. Galway.

All seed and larger oysters brought into the Bay have to be sourced from a hatchery as per instruction

of the Clew Bay Oyster Co-operative and as agreed under the Clew Bay CLAMS Code of Practice

(below). To date, none of the growers have witnessed or are aware of any successful settlement and

recruitment of pacific oysters to the wild as a consequence of diploid culture within the Bay.

Hatcheries from which seed are sourced in recent years are:

Seasalter, England

Guernsey , Channel Isles

France Naissain, France

France Turbo, France

Satmar, France

Gran Ocean, France

There has been a general shift in the Bay in moving totally or almost totally away from using diploid

seed sourced from the UK hatcheries. Since 2008 the majority of the seed is from French hatcheries

and is over 80% Triploid. While in the past, seed was generally imported in the spring time, it is now

imported between February and June and between August and October. This change has been brought

about because of high demand on hatchery seed. Therefore, sourcing of seed is often dependent on

availability.

Since 2008, the majority of the oyster producers in the Bay have concentrated on producing ½ grown

oysters (20g – 45g) for selling onto other Irish and French oyster producers. Approximately 90% of the

seed introduced into the Bay each year is now transferred out of the Bay within 18 months. One

producer is also contract growing for another producer from another Irish bay. In this instance, oysters

are introduced into Clew Bay during the spring at a size 10 to 25 gram and are grown for one year after

which they are transported back to original bay for finishing off for market. Oysters that remain in the

bay for further on-growing reach market size of 65 gram plus within on average 3 years.

Stocking densities and stock management (thinning, splitting and grading stock) varies with each oyster

producer. In general grading and exporting of ½ grown oysters takes place from September to April,

and harvesting of stock for mature oysters for market takes place from October to May. Initial stocking

densities when deployed into 4mm bags can vary from 800 up to 5000 oyster seed per bag. As the

oysters grow stocking densities are reduced. Generally seed if stocked over 2000/bag is split in the

first couple of months to lower density and by the end of year one the density is between 400 and 1000

oysters per bag. By the time they reach market size of 66 gram plus in year 3, the stocking density is

19

down to between 100 and 150 per bag. Thinning, grading and harvesting activities entails removing

oyster bags from the trestles by hand and transporting them on tractor and trailers or boat from the

intertidal zone to the grower’s land based facilities almost all located on the shore around Clew Bay.

The two main pacific oyster production areas within Clew Bay are Tiernaur and Murrisk. There are also

4 individual farms located in Inner Clew Bay in Kilmeena – Carrowholly area and there are 2 licences

on 2 islands (Clynish and Inishraher).

Tiernaur: The Tiernaur pacific oyster growing area is located in the north of the Bay and this is where

the majority of the ½ grown oysters are produced. There are 4 producers here, one whom has also a

site in Clew Bay South. Three of the producers observe one dedicated access route out from shore

access point to their general site area and at any one time there will up to 5 tractors and trailers in this

growing area of Tiernaur. The sites here are accessed on average between 12 and 18 days per month

depending on time of year. The other producer uses a different dedicated access route to his farm as

it is located further east. They only use the tractor and trailer at times of collecting stock for grading

and sales, otherwise the site is accessed by foot.

Murrisk: The Murrisk pacific oyster growing area is located in the south of the Bay. There are 3 active

producers in this area who observe three dedicated access routes from the shore access points and a

land based facility. At any one time depending on times of grading and selling stock there can be up

to 3 tractors and trailers operating across the area. The sites here are accessed up to a maximum 12

days each month. On days the tractors and trailers are not required, producers access sites by foot.

The remaining intertidal growing areas in Clew Bay are located in the Kilmeena-Carrowholly general

area, (plus 2 sites located on 2 islands) and are all single individual producers. Almost all are based

adjacent to their land based facilities. One of the main producers uses a flat bottom boat to access and

work on site rather than a tractor and trailer.

5.1.2 Subtidal Oyster culture

Subtidal extensive culture of oysters involves the placement of oysters in an uncontained fashion on

the seabed after a nursery phase in the intertidal zone. It is proposed that suitably sized shellfish are

spread within the licenced area. Stock will be checked periodically when the progress (growth and

mortality) of the stock will be monitored and intervention will be necessary if anomalies are discovered.

For example, shellfish may need turning-over if excessive fouling or siltation is noted on the animals.

Such intervention, as well as harvesting, will be carried out using oyster dredges deployed from boats.

The oyster dredges are typically 1.5m wide and have contact with the substrate via a flat blade. Harvest

is expected 24-36 months after initial seeding for oysters. This may be shorter depending upon the size

of the seed and the production capabilities of the area in question.

5.1.3 Rope Mussels

Trials on rope mussel (Mytilus edulis) farming began in Clew Bay in 1979, and initially generated only

a few tonne. Today there is only one producer who has been operating in the bay since 1984. The

company operate on two licensed sites, one located north of Inishlaughil within Inner Clew Bay, and the

20

other on a more exposed site beside Moynish Beg in Clew Bay North. All mussel grading and packing

equipment and machinery are on-board their adapted mussel boat. From time to time during busy

periods they also use another vessel for general maintenance on site. Site access is generally from

Inishcottle pier, located just over 1 km south of the farm and occasionally from Rosmoney pier further

south. All mussel seed is collected on lines deployed for this purpose within the licensed sites in Clew

Bay. No mussel seed is imported to the bay from other areas.

The method of production used by this company from 1984 to 2004 was the traditional double headed

longline and single dropper system which involved placing naturally collected local mussel seed

(collected on mesh and rope) into plastic mesh stockings , known as pergolari. These stockings were

suspended in the water column on floating rope long-lines and mussel floats.

In 2004 the company adapted the New Zealand continuous longline system of cultivation. This

automated method involves continuous seeding of entire loops of culture rope over 200 metres in length

rather than the single dropper system. This system where packing and harvesting is mechanised,

allows mussel farmers to produce a high value seafood product efficiently, using environmentally

sustainable techniques. The grow ropes (which the mussels attach to) can be recycled and re-used for

many years. The collector mesh or cotton stocking – that holds the mussels to the rope while they adapt

to their new environment - is biodegradable. The Clew Bay mussel producer which produce organic

mussels in accordance with EU Organic Regulations, has further grown its business and now produces

this cotton mesh at their land based facility in Westport to supply the Irish and European rope mussel

industry.

Rope mussels like other bivalve molluscs obtain their food by filtering microscopic algae from the water

column. Mussel seed / spat are collected on site in Clew Bay between May and June and reaches

market size within 24 months. During this grow cycle the mussels can be graded up to three times and

this allows the almost continuous supply of market size mussels all year round. The majority of the

product is delivered directly by boat into one of the main Irish shellfish and mussel processors and

exporters located on the shore of inner Clew Bay.

There are currently aquaculture licence applications for an additional two rope mussel farms to be

located within Inner Clew Bay from applicants who have been involved in the aquaculture industry in

the past.

5.1.4 Salmon Culture

Finfish farming began in inner Clew Bay in 1975 and in the outer bay at Clare Island in 1986. Both

Salmon (Salmo salar) and Rainbow trout (Oncorhynchus mykiss) were grown at sites in inner Clew Bay

up until 2011. Today production is only salmon and all production is from a single company, MOWI,

who produce certified organic salmon in accordance with the EU Organic Regulations. The company

is a fully integrated salmon farm who operates at sites in Counties Donegal, Mayo, Kerry and Cork.

Marine Harvest Ireland carries out all phases of their salmon business, starting with the taking of ova

from broodstock to the harvesting and packaging of the final product.

21

The production cycle starts in freshwater hatcheries in Co. Donegal where ova are stripped and fertilised

from broodstock fish from Mulroy Bay in early winter, typically November. The company has 3

hatcheries and 2 smolt production units in Co. Donegal that produce the young salmon which are ready

to go to sea at the smolt stage of the salmon lifecycle. Marine Harvest Ireland produces both Spring

and Autumn smolts.

In Co. Mayo, Marine Harvest Ireland operate from 4 sea sites in Clew Bay - two at Clare Island and two

at Inner Clew Bay. One of the Clare Island sites is used for rearing the Donegal supplied smolts. As

they grow the salmon are transferred to the other Clare Island site. Once at sea the smolts are reared

to market size in nets suspended from circular floating structures known as pens. These are moored

in groups in locations where there are strong water flows in order to provide the stock with optimum

environmental conditions. The company uses automatic feeding systems in conjunction with

underwater camera for observation of fish feeding behaviour. The feeding systems are calibrated daily

by site staff, in accordance with fish appetite and environmental conditions.

The two site areas within Inner Clew Bay are used for ongrowing salmon. Typically the salmon are

transferred from the Clare Island sites to these Inner Bay sites in September of every year and are

reared for up to eight months or slightly longer until they reach harvest size. Usually the Inner Bay sites

are only used for eight months of the year and remain fallow for four months from June to September.

These inner sites are accessed from Roigh Pier on the north of Clew Bay and on occasion from the

company’s shore base located beside Cloghmore Pier, South Achill Island. When the salmon are ready

for market, at size greater than 3 kg, they are transferred from the sea pens into a well-boat to a harvest

(stun & bled) unit first before they are transferred by road tankers to the company’s processing unit in

Co. Donegal. No blood or effluent from the harvest process is discharged back to sea as it is collected

with the harvest fish in the road tankers and disposed of in the company’s licensed effluent treatment

plant at the processing plant.

5.1.5 Scallop

Initial trials in the cultivation of King scallop (Pecten maximus) began in the 1990s and continued into

the 2000s. Seed scallop was sourced from natural wild settlement (Mulroy Bay) or from a hatchery

(Cartron Point, Co. Clare) and were put into protective enclosures or suspended on long-lines until they

reached size of 40mm plus, after which time they were placed on the seabed in frames or under

protective covering until they reached maturity within 4 to 5 years and marketable size of greater than

100mm in width. The sporadic supply of scallop seed on an annual basis over the past 10 years has

meant that production in the bay on these sites is only on a small scale. The current licence relays seed

at size 40mm directly onto seabed in low stocking densities. The market size scallops are harvested

by divers.

5.1.6 Clew Bay Seaweed Cultivation

It is proposed to cultivate seaweed within as site already licensed for the culture of rope mussels

Blackshell Farms Ltd. wish to grow seaweed – ( various red, brown and green seaweeds) on the

northern section of site T10/301A. The area size for this project is circa 3 hectares. The intensive

22

cultivation of seaweed on longlines is relatively new to Ireland. Currently there are few sites growing

kelp seaweed species using the single headrope longline system and other new systems.

Seeded nets and string will be sourced from Irish Hatcheries e.g. Bantry.

The growing system consists of a grid 160 metres by 65 metres , using 9 X 1100 litre buoys. There will

be 32 hanging seaweed growing nets wich will measure 4 metres in depth and 80 m in length. The grid

will use 36mm polysteel gridrope and steel grid rings to keep whole grid in shape. The seaweed will

be harvested using the Company’s existing mussel workboat and equipment. The lines and nets will

be stripped of seaweed at site and packed into one tonne bags and brought ashore where it will be

dried and processed.

All floatation buoys will be grey in colour and site is already marked with yellow special markers with

approval of CIL and MSO.

5.1.7 Clams

In the late 1980s and early 1990s the Manilla Clam – (Venerupis philippinarum) was grown in two

intertidal area on a few sites in Clew Bay in bags, tray mesh containers and on the seabed in clam

parks and under mesh. Seed was imported from hatcheries (Co. Sligo and Seasalter,UK) at size 8mm

– 12mm and grown in trays and bags for one year after which time they were sown on intertidal ground

under mesh. They reach adult market size within a year.

Today clams are only grown on a very small scale, less than 1 tonne per annum on one site alongside

pacific oysters in inner Clew Bay. They are locally sourced as seed or at juvenile stage and are grown

in oyster bags on the ground and on trestles on the lower intertidal ground area. Some are grown

directly on ground and are harvested by hand. They are sold onto the local and regional retail

marketplace.

5.1.8 Abalone

The abalone also known as Ormer is not native to Ireland and will not breed in our colder waters. It

looks like a limpet, in that it has one shell. Both the European abalone –Haliotis tuberculata and

Japanese – Haliotis discus have been introduced into Ireland. Trials began on abalone in the early

1980's and Clew Bay was host in the 1990s to the only on-growing sea site in Ireland. The juvenile

abalone were put into protective containers and cages and were fed Laminaria (kelp) and Palmaria

(dillisk), by divers, every two weeks in summertime and every four to six weeks in the winter. The growth

cycle is about five years and the principle market, was an established local and Irish market.

The cultivation of abalone in Clew Bay ceased in the early 2000s but there is currently a single licence

for on-growing the European Abalone in new structures at a new site adjacent to one the islands,

Inishcorky, in the north of the Bay. This project proposes to import juvenile abalone from a French

hatchery, at size 15mm and ongrow them in plastic containers called ‘Ortacs’ in an area below the low

water mark. The Ortacs will be suspended between one and three metres above the seabed on

longlines in the water column with use of floats. The abalone will be fed fortnightly with natural dried

and sterilised macroalgae (Laminaria and Palmaria) imported from Spain and UK. It is envisaged that

23

they will reach market size of 50 mm plus in this system within 4 years. The site will be accessed

primarily from Roigh Pier which is located less than 4km to the northeast of the site. The activity at this

site has been subject to a full risk assessment under Council Regulation (EC) No 708/2007 concerning

use of alien and locally absent species in aquaculture.

5.1.9 Lobster

A trial licence existed in the mid-2000s at site south of Island More for the cultivation of Lobster

(Homarus gammarus) using galvanised steel trestles on the seabed. A new application for the

cultivation of lobster and crawfish (Palinurus elephas) has been lodged using plastic trestles on the

seabed in lines. It is proposed that small lobster and crawfish bought from local fishermen at legal size

would be placed in individual plastic containers with galvanised mesh and frames on the seabed. They

will be fed, e.g. with mussels and other food, by hauling the frames to the sea surface using a boat.

They can also be fed with use of a diver. As in the trial the lobster will increase in biomass by 30%

within 6 to 8 months and will be ready for the Christmas export market.

5.1.10 Hatchery Operations

A single licence is held for the cultivation of salmon, rainbow trout and brown trout at a facility on the

shore of Lough Furnace (Coastal Lagoon). The system is entirely land based with water extracted from

Lough Feeagh and discharged into Lough Furnace after treatment. The hatchery is licenced to produce

up to 250,000 smolts pa. The discharge is fully treated and the facility is in possession of a licence to

discharge to surface waters consented by Mayo County Council.

5.1.11 Clew Bay CLAMS

The Clew Bay CLAMS Group which was established in 2001, is composed of representatives of all

bona fida aquaculture interests such as the finfish and shellfish producers, the Clew Bay Oyster Co-

operative, the Clew Bay Marine Forum, liaison officers and relevant BIM and Marine Institute officers.

The Clew Bay CLAMS Document was drawn up in late 2001. The CLAMS process initiated a ‘Code of

Practice’ document which was published in 2003. The primary aim of the Code of Practice is to further

promote the responsible development and management of the Clew Bay Aquaculture Sector, assuring

the highest standards of quality food production while respecting environmental considerations,

consumers’ demands and other bay users. It covers matters relating to Stock Health Management,

Site Management, Visual Impact, Navigation, Environmental Monitoring, Use of Public Pier, Waste

Management, Nature Conservation, Health & Safety and Communication. An example of two of the

agreed terms from the Clew Bay CLAMS Code of Practice are:

‘No oyster stock must be imported in Clew Bay, which has originated in France as wild seed

stock’.

To use a single access route to intertidal sites, minimise journey trips and drive slowly in order

to minimise disturbance and any potential damage to existing benthic flora and fauna.

24

Figure 5: Aquaculture sites (Licenced and Applications) and access routes in Clew Bay Complex SAC (access routes not drawn to scale)

25

Table 3: Spatial extent (ha) of aquaculture activities overlapping with the qualifying interest (1140 -Mudflats and sandflats not covered by seawater

at low tide and 1160-Large shallow inlets and bays) in Clew Bay Complex SAC, presented according to culture species, method of cultivation and

license status.

Species Status Location

1140 - Mudflats and sandflats not covered by

seawater at low tide (1,277ha)

1160 - Large shallow inlets and Bays (10,198ha)

Area (ha) % Feature Area (ha) % Feature

Oysters Licensed Intertidal 57.72 4.52 171.2 1.68

Oysters Application Intertidal 6.27 0.49 22.6 0.22

Mussels Licensed Subtidal - - 64.5 0.63

Mussels Application Subtidal - - 60.55 0.60

Finfish Licensed Subtidal - - 15.96 0.16

Scallops Licensed Subtidal - - 4 0.04

Lobster Licensed Subtidal - - 1.0 <0.001

Abalone Licenced Subtidal - - 2.64 0.03

Access Routes 6.71 0.53 10.09 0.1

Corrected Totals* 70.7 5.54 352.54 3.42

*Corrected Totals refer to total spatial coverage of activity that will occur if certain licenced sites are surrendered on foot of successful new applications or realignment of sites (see Section 5.1) and do not reflect the sum of columns in the table.

26

5.2 Fishing activities

Fishing activities in Clew Bay were profiled through a questionnaire survey completed by BIM in 2011,

this is still the most current information upon which to base as risk assessment. There were 26 vessels

fishing in the Clew Bay area in 2011 and information on all 26 are included in the descriptions below.

Not all 26 vessels fish within the SAC. Vessels range in size from 4.9 to 18m but 25 are less than 12m

and 21 and less than 10m. At least 15 fish species are targeted across 11 métiers (gear_target species

combination). Gears used include shrimp pots, lobster creels, top entry pots, prawn pots, dredges,

tangle nets, trammel nets, gill nets, bottom trawls, mid-water trawls, various forms of hooks and lines

and hand gathering. Individual operators may target different species (belong to different métiers) in

different seasons.

5.2.1 The fleet

The fishing fleet operating in Clew Bay is an inshore fleet (Table 4). There are 26 vessels varying in

size from 4.95-12m with one exception which is 16.6m in length. Twenty one vessels are under 10m

and 4 between 10-12m. Sixteen of the vessels have polyvalent licences which allows them access to

all commercial species fished in the bay other than oyster which also requires a secondary licence

which is issued by IFI. Seven of the vessels are restricted to using pots only (so called P licences) and

3 vessels are licenced in the Aquaculture segment of the fleet. Aquaculture vessels may dredge for

oysters provided they have an IFI oyster permit.

Table 4: The inshore fishing fleet in Clew Bay

Vessel type

Port Decked Half

decked Open Total

Westport 6 6

Clare Is 1 1

Mulranny 2 1 3

Newport 1 1

Inis Lyre Is 1 1

Roigh 1 2 2 5

Clynish Is 1 1 2

Old Head 1 1 2

Cloghmore 2 2

Murrisk 1 1

Kilmeena 2 2

Total 19 2 5 26

27

5.2.2 Potting for shrimp

Fifteen vessels fish for shrimp using a total of approximately 6900 shrimp pots (Figure 6). The pots are

fished in strings of 20-30 pots which are interconnected on the seabed by rope. The gear is in the water

during the shrimp open season from Aug 1st to April 31st although fishing effort is much lower in spring

from February onwards. Each set of gear may be hauled 3 days per week depending on weather, catch

rates and market conditions. Pots are baited with frozen mackerel, herring and scad which is purchased

ashore. Some fishermen fish for bait using trammel nets to catch wrasse, dogfish and whitefish.

Although shrimp are fished throughout the bay at some time during the season vessels tend to have

their own areas or territories and effort is higher in shallow areas in the inner bay in the period Aug-Oct

and in deeper water outside the SAC area from November onwards. This pattern follows the migration

of shrimp to deeper water as temperatures decline.

Figure 6: Distribution of shrimp fishing, derived from expert data, in relation to Clew Bay SAC

5.2.3 Potting for prawns

A small scale pot fishery for prawns occurs in the middle area of the bay in mud and sandy mud

substrates (Figure 7). Three fishermen are involved on a seasonal basis. The fishery occurs in May and

again from October to December. Pot numbers vary from 300 in May to 1150 in October-December.

Prawns are landed and sold live. Significant high grading on the vessels occurs whereby a significant

proportion of small prawns are returned alive to the sea.

28

Figure 7: Distribution of fishing for lobster, crab and prawns in relation to the Clew Bay SAC

5.2.4 Potting for crab and lobster

A total of 16 fishermen use soft eye creels to fish for lobster and brown crab and velvet crab. Seven of

these fishermen also use top entrance pots for spider crab. Pot numbers per vessel varies from 250-

600. The gear is fished throughout the year with higher levels of activity in the period Apr-Sept. Pot

numbers reach 4800 in mid-summer. Lobster is the primary species for 16 of the 26 fishermen in the

Bay.

5.2.5 Potting for whelk

A new pot fishery for whelk began in 2013 with 2 vessels operating 400 pots each. The fishery occurred

from the estuary of the Newport River seaward to deeper waters and on sub-tidal sedimentary habitats.

The stock has apparently declined and is unlikely to support a fishery.

5.2.6 Tangle netting for crayfish

Three fishermen fish for crayfish with tangle nets and use a total of 11km of nets. Approximately 3km

is used in the SAC and 8km in other areas of Clew Bay (Figure 8). Peak fishing time occurs from May-

Sept and nets are in the water from Apr to Nov. The gear is in the water for prolonged periods and

probably over 20 days per month.

29

Figure 8: Distribution of tangle netting for crayfish in relation to the Clew Bay SAC

5.2.7 Gill netting for Pollack and other netting

Set gill nets are used to target mainly Pollack. In Clew Bay 5 vessels use approximately 7.6km of gill

nets (Figure 9).

An estimated 3km may be used in the SAC. The fishery is active from Jan-Sept but mainly from May-

Aug.

Drift netting for mackerel is carried out by 1 vessel for approximately 10 days per month during May to

Sept.

30

A number of fishermen in 6m vessels set drift nets for herring in autumn in the inner Bay. Catches are

generally low and amount to 3-4 boxes per vessel for the season.

Figure 9: Distribution of Pollack and mackerel gill netting and trolling in relation to the Clew

Bay SAC

5.2.8 Dredging for scallop

Scallops are mainly fished in autumn and winter in Clew Bay (Figure 10). However, of the 10 fishermen

who may fish for scallops two indicated they fish for 8 months of the year. Scallop occurs in shallow

cobble and gravel substrates at 10-20m depth surrounding islands in the inner Bay and in deeper water

outside the SAC. The fishery may be restricted and closed periodically due to high levels of biotoxins

in the flesh of scallops which prohibits their sale in to the market.

Figure 10: Distribution of scallop fishing, derived from survey data and expert data, in relation

to Clew Bay SAC

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5.2.9 Dredging for oyster

There was previously an important fishery for native oyster in Clew Bay (Figure 11). The stock is now

depleted but a limited commercial fishery occurs in the autumn of each year. The spatial extent of the

fishery is not definitely known but recent survey data indicates the probable distribution of areas which

have commercial, albeit at low densities, quantities of oysters. Native oyster was listed as top priority

species for 3 fishermen in Clew Bay in 2011. Oysters are fished from vessels under 10m in length using

fixed toothed dredges. One dredge, measuring approximately 1.2m in width, is used by each vessel.

Licences to fish for oyster are issued annually by IFI. Six licences were issued in 2013 for the Ballinakill

area which includes the south side of Clew Bay and Clare Island. 49 licences were issued in the Bangor

district which includes north side of Clew Bay and other areas north of Clew Bay.

Figure 11: Distribution of oyster fishing, derived from survey data, in relation to Clew Bay SAC

5.2.10 Bottom trawling for mixed demersal fish

The bottom trawl fishery targets a wide range of species including monkfish, prawns, whiting, haddock,

pollack, skates, rays, john dory and gurnard (Figure 12). Four vessels are involved. The fishery

operates year round in sandy substrates in the outer middle and north of the bay.

32

Figure 12: Distribution of bottom trawl fishing, derived from VMS data (vessels >15m) and

expert data, in relation to Clew Bay SAC

5.2.11 Mid-water trawling for pelagic fish

No local boats are involved in the pelagic fishery (Figure 13). Larger pelagic vessels from Killybegs,

Rossaveal and Castletownbere often fish the outer Bay in late autumn and winter.

Figure 13: Distribution of mid-water trawling as shown by VMS data (vessels>15m).

5.2.12 Hook and line fishing for mackerel and Pollack

This fishery uses a wide variety of gears best described as trolling lines and bottom set lines operated

from mechanized and manual jigging machines. Sixteen vessels report using some form of

trolling/jigging gears. Activity is concentrated in the period May to Oct.

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5.2.13 Draft net fishing for salmon

The maximum number of fishing licences for salmon, using draft nets, in District number 10 (Ballinakill

and Bangor) in 2013 was 40. Such licences, if activated could fish for salmon in rivers estuaries within

the district where salmon stocks have exceed their conservation limits (as determined by the Salmon

Standing Scientific Committee) and there is a surplus of fish to be taken and if a proportion of that

surplus is allocated to draft net fishing (SI 75/2013, Schedule 1).

In reality only 1 draft net licence operated in Clew Bay in 2012. This was fished in the Newport river

estuary in June-July. The TAC was limited to 50 fish. In addition a private licence, to fish for draft net,

exists in the Bunowen River on the south east corner of the Bay again when the salmon stock exceeds

conservation limit.

5.2.14 Trammel net fishing for bait

Although the majority of pot fishermen purchase bait (frozen pelagic) ashore some fishermen use

trammel nets to fish for wrasse, pollack and dogfish which are used as bait in pots. The fishery is likely

to occur at the edges of reef areas and may be more localized than indicated in Figure 14.

Figure 14 Distribution of trammel netting for bait in relation to the Clew Bay SAC.

5.2.15 Hand gathering of periwinkle and cockle

Fishing for periwinkle is common and sometimes intensive in the inner Bay on semi exposed shores on

the mainland and on islands in the Bay (Figure 15). The spatial distribution and intensity of the activity

is not known.

Cockles are common and sometimes abundant in an area east of Mullranny on intertidal muddy sand

shores. There is no commercial dredge fishery for cockles in this area but some hand gathering may

occur.

34

Figure 15: Distribution of cockle stocks, derived from survey data, in Clew Bay SAC

35

6 Natura Impact Statement for the proposed activities

The potential ecological effects of activities on the conservation objectives for the site relate to the

physical and biological effects of fishing gears or aquaculture structures and human activities on

designated species, intertidal and sub-tidal habitats and invertebrate communities and biotopes within

those broad habitat types. The overall effect on the conservation status will depend on the spatial and

temporal extent of fishing and aquaculture activities during the lifetime of the proposed plans and

projects and the nature of each of these activities in conjunction with the sensitivity of the receiving

environment.

6.1 Aquaculture

Within the qualifying interest of Clew Bay Complex SAC, the species cultured are:

1. Oysters (Crassostrea gigas), in suspended culture (contained in bags & trestles) confined

primarily to intertidal areas.

2. Mussels (Mytilus edulis) in suspended culture in subtidal areas.

3. Oysters (Crassostrea gigas) subtidally on the seafloor.

4. Clams (Venerupis philippinarum) intertidally on the seafloor.

5. Scallop (Pecten maximus) in suspended culture in subtidal areas.

6. Lobster (Homarus gammarus) in subtidal areas.

7. Abalone (Haliotis sp.) in subtidal areas.

8. Atlantic salmon (Salmo salar) in net pens.

Details of the potential biological and physical effects of these aquaculture activities on the habitat

features, their sources and the mechanism by which the impact may occur are summarised in Table 5,

below. The impact summaries identified in the table are derived from published primary literature and

review documents that have specifically focused upon the environmental interactions of mariculture

(e.g. Black 2001; McKindsey et al. 2007; NRC 2010; O’Beirn et al 2012; Cranford et al 2012; ABPMer

2013a-h).

Filter feeding organisms, for the most part, feed at the lowest trophic level, usually relying primarily on

ingestion of phytoplankton. The process is extractive in that it does not rely on the input of feedstuffs in

order to produce growth. Suspension feeding bivalves such as oysters and mussels can modify their

filtration to account for increasing loads of suspended matter in the water and can increase the

production of faeces and pseudofaeces (non-ingested material) which result in the transfer of both

organic and inorganic particles to the seafloor. This process is a component of benthic-pelagic coupling

(Table 5). The degree of deposition and accumulation of biologically derived material on the seafloor is

a function of a number of factors discussed below.

One aspect to consider in relation to the culture of shellfish is the potential risk of alien species arriving

into an area among consignments of seed or stock sourced from outside of the area under

consideration. When the seed is sourced locally (e.g. mussel culture) the risk is likely zero. When seed

36

is sourced at a small size from hatcheries in Ireland the risk is also small. When seed is sourced from

hatcheries outside of Ireland (this represents the majority of cases particularly for oyster culture

operations) the risk is also considered small, especially if the nursery phase has been short. When ½-

grown stock (oysters and mussels) is introduced from another area (e.g. France, UK) the risk of

introducing alien species (hitchhikers) is considered greater given that the stock will have been grown

in the wild (open water) for a prolonged period (i.e. ½-grown stock). It is important to note that the

importation of ½-grown wild oysters into Clew Bay is prohibited under Fishery Order Cooperative rules

and CLAMs agreement (see Sections 5.1.1 and 5.1.10 above). Furthermore, the culture of a non-native

species (e.g. the Pacific Oyster - Crassostrea gigas) may also presents a risk of establishment of this

species in the SAC. Recruitment of C. gigas has been documented in a number of Bays in Ireland and

appears to have become naturalised (i.e. establishment of a breeding population) in two locations

(Kochmann et al 2012; 2013) and may compete with the native species for space and food. The culture

of large volumes of Pacific oysters may increase the risk of successful reproduction in Clew Bay

Complex SAC. The use of triploid (non-reproducing) stock is the main method employed to mange this

risk. To date, no settlement of Pacific oysters has been reported in Clew Bay.

Suspended Shellfish Culture: Suspended culture, may result in faecal and pseudo-faecal material

falling to the seabed. In addition, the loss of culture species to the seabed is also a possibility. The

degree to which the material disperses away from the location of the culture system (longlines or

trestles) depends on the density of mussels on the line, the depth of water and the current regime in

the vicinity. Cumulative impacts on seabed, especially in areas where assimilation or dispersion of

pseudofaeces is low, may occur over time. A number of features of the site and culture practices will

govern the speed at which pseudofaeces are assimilated or dispersed by the site. These relate to:

1. Hydrography – will governs how quickly the wastes disperse from the culture location and the

density at which they will accumulate on the seafloor.

2. Turbidity in the water - the higher the turbidity the greater the production of pseudo-faeces and

faeces by the filter feeding animal and the greater the risk of accumulation on the seafloor.

3. Density of culture – suspended mussel culture is considered a dense culture method with high

densities of culture organisms over a small area. The greater the density of organisms the

greater the risk of accumulations of material. The density of culture organisms is a function of:

a. depth of the site (shallow sites have shorter droppers and hence fewer culture

organisms),

b. the husbandry practices – proper maintenance will result in optimum densities on the

lines in order to give high growth rates as well as reducing the risk of drop-off of culture

animals to the seafloor and sufficient distance among the longlines to reduce the risk

of cumulative impacts in depositional areas.

In addition, placement of structures associated with mussel culture can influence the degree of light

penetration to the seabed. This is likely important for organisms and habitats e.g. maerl and seagrasses

which need sun light for production. Rafts or lines will to a degree limit light penetration to the sea bed

37

and may therefore reduce production of photosynthesising species. However, such effects have not

been demonstrated for seagrass.

Intertidal Shellfish culture: Oysters are typically cultured in the intertidal zone using a combination of

plastic mesh bags and trestles. Their specific location in the intertidal is dependent upon the level of

exposure of the site, the stage of culture and the accessibility of the site. The habitat impact from oyster

trestle culture is typically localised to areas directly beneath the culture systems. The physical presence

of the trestles and bags may reduce water flow and allowing suspended material (silt, clay as well as

faeces and pseudo-faeces) to fall out of suspension to the seafloor. The build-up of material will typically

occur directly beneath the trestle structures and can result in accumulation of fine, organically rich

sediments. These sediments may result in the development of infaunal communities distinct from the

surrounding areas. Whether material accumulates is dictated by a number of factors, including:

1. Hydrography – low current speeds (or small tidal range) may result in material being deposited

directly beneath the trestles. If tidal height is high and large volumes of water moved through

the culture area an acceleration of water flow can occur beneath the trestles and bags, resulting

in a scouring effect or erosion and no accumulation of material.

2. Turbidity of water – as with suspended mussel culture, oysters have very plastic response to

increasing suspended matter in the water column with a consequent increase in faecal or

pseudo-faecal production. Oysters can be cultured in estuarine areas (given their polyhaline

tolerance) and as a consequence can be exposed to elevated levels of suspended matter. If

currents in the vicinity are generally low, elevated suspended matter can result in increase

build-up of material beneath culture structures.

3. Density of culture – the density of oysters in a bag and consequently the density of bags on a

trestle will increase the likelihood of accumulation on the seafloor. In addition, if the trestles are

located in close proximity a greater dampening effect can be realised with resultant

accumulations. Close proximity may also result in impact on shellfish performance due to

competitive interactions for food.

4. Exposure of sites - the degree to which the aquaculture sites are exposed to prevailing weather

conditions will also dictate the level of accumulated organic material in the area. As fronts move

through culture areas increased wave action will resuspend and disperse material away from

the trestles.

Shading may be an issue as a consequence of the structures associated with intertidal oyster culture.

The racks and bags are held relatively close to the seabed and as a consequence may shade sensitive

species (e.g. sea grasses) found underneath.

Sub-tidal oyster culture: This activity involves relaying oysters on the seabed. There may be

increased enrichment due to production of faeces and pseudofaeces. The existing in-faunal community

may be changed as a result. Seabed habitat change may also result as a result of dredging during

maintenance and harvesting. Uncontained sub-tidal shellfish culture will lead to change in community

structure and function through the addition, at high % cover, of an epi-benthic species (living on the

seabed) to an infaunal sedimentary community.

38

The activities associated with this culture practice (dredging of the seabed) are considered disturbing

which can lead to removal and/or destruction of infaunal species and changes to sediment composition.

In addition, the location of large numbers of a single epifaunal species onto what is, in essence, an

infaunal dominated system will likely result in a change to the habitat.

Physical disturbance caused by compaction of sediment from foot traffic and vehicular traffic.

Activities associated with the culture of intertidal shellfish include the travel to and from the culture sites

and within the culture sites using tractors and trailers as well as the activities of workers within the site

boundaries.

Other considerations: Intertidal culture of clam species is typically carried out in the sediment covered

with netting to protect the stock from predators. The high density of the culture organisms can lead to

exclusion of native biota and the ground preparation and harvest methods (by mechanical means or by

hand) can lead to considerable disturbance of biota characterising the habitat.

Due to the nature of the (high density) culture methods the risk of transmission of disease within cultured

stock is high. However, given that Crassostrea gigas does not appear to occur in the wild the risk of

disease transmission to ‘wild’ stock is considered low. The risk of disease transmission from cultured

oysters to other species is unknown.

Introduction of Non-native species - All culture methods: Movement and introduction of bivalve

shellfish (and equipment) can be a vector for the introduction and spread of non-native/alien species.

In some instances the introduced species may proliferate rapidly and compete with and in some cases

replace the native species. Recruitment of C. gigas has been documented in a number of bays in Ireland

and appears to have become naturalised (i.e. establishment of a breeding population) in some

(Kochmann et al., 2012; 2013) and may compete with the native species for space and food.

Another means is the unintentional introduction of non-native species/diseases which are associated

with the imported target culture species (or equipment), and their subsequent spread and

establishment. These associated species are referred to as ”hitch-hikers” and include animals and

plants and/or parasites and diseases that potentially could cause outbreaks within the culture species

or spread to other local species.

Finfish Culture: Finfish (Salmon) Culture: Within the Clew Bay Complex SAC there are five marine

sites and 1 terrestrial site assigned for the culture of salmon (and other finfish). The marine sites are all

located in the northern part of the Bay and the land-based site is located adjacent to the Furnace Lough

(Coastal Lagoon).

Finfish culture differs from shellfish culture in that there is an input of feed into the system and as a

consequence a net input of organic matter to the system. This material will be found in the system in

the form of waste feed (on the seafloor), solid waste (faeces), waste as a consequence of net-cleaning

all of which usually accumulates on the seafloor and dissolved material (predominantly fractions rich in

nitrogen). For the most part, the majority of organic material builds up on the seabed generally in and

around the footprint of the salmon cages with a ‘halo’ effect evident in areas where dispersion occurs

driven by local hydrographic conditions. This is typically referred to a near-field effects. Similar to

39

shellfish, the quantity of material that might accumulate on the seabed will be a function of the quantity

of fish held in cages, the stage of culture, the health of the fish (unhealthy fish will generally eat less),

husbandry practices (are the fish fed too much too quickly?), the physical characteristic of the solid

particles and, as mentioned above, hydrographic conditions.

Wildish et al. (2004) and Silvert and Cromey (2001) both summarize the factors (listed above) that

govern the level of dispersion of material from the cages to the seafloor. Many of the factors are

subsequently incorporated into modelling efforts which are used to predict likely levels of impact. The

impact of organic matter on sedimentary seafloor habitat (as found beneath fish structures in Clew Bay)

typically evolves after the gradient defined by Pearson-Rosenberg (1978), whereby as the level of

organic enrichment increases the communities (macrofaunal species number and abundance) found

within the sedimentary habitats will also change. Typically, low levels of enrichment facilitates an

increase in species abundance and biomass followed by a decrease in all biological metrics as

enrichment increases to a point where azoic conditions prevail and no biota are found. The impact on

biota is a consequence of the decrease in oxygen and a build-up of by-products such as ammonia and

sulphides brought about by the break down of the organic particles which are considered toxic to marine

biota. The shift from an oxygenating to reducing environment in the sediment could be such that the

effect is mirrored in the water column as well (i.e. reduction in oxygen levels). The output of dissolved

material resulting from finfish cages is typically in the form of ammonia, phosphorous and dissolved

organic carbon (DOC) originating directly from the culture organisms, or from the feed and/or faecal

pellets. Similar to particulate waste, the impact of dissolved material is a function of the extent (intensity)

of the activity and properties of the receiving environment (e.g., temperature, flushing time). While

elevated levels of nutrient have been reported near fish farms, no significant effect on chlorophyll has

been demonstrated (Pearson and Black, 2001).

Diseases: It is likely that the first outbreaks of infectious diseases in marine aquaculture operations

were caused by pathogens originating in wild hosts and as culture extent and intensity increases the

transmission of pathogens (back) to the wild fish stocks is a likely consequence (Jones et al., in prep).

The result of such pathogen transmission back to wild fish is however unknown, as reports of clinical

effects or significant mortality in wild fish populations are largely unavailable. Numerous reviews,

models, risk assessments and risk analysis have been carried out or developed in order to determine

the potential for disease interaction and pathogen exchange between farmed and wild finfish (OIE 2004,

Bricknell et al. 2006, DIPNET 2006, Peeler et al. 2007). On foot of these outputs there is general

acceptance among scientists and managers that pathogens can be transmitted between organisms

used in mariculture and those found in the wild and vice-versa (ICES 2013).

The risk of infection in marine organisms, are influenced by a number of environmental factors including

temperature, salinity and dissolved oxygen (Grant and Jones 2011), as well as factors particular to the

biology of pathogen, e.g., replication rates, virulence. Transmission of pathogens is facilitated by one

or a combination of three mechanisms, i.e., horizontal, vertical and vector-borne. Horizontal

transmission refers to the direct movement through the water column of a pathogen between

susceptible individuals and the open design of most mariculture cages allows the potential for

40

bidirectional transmission of pathogens between wild and captive fish (Johansen et al. 2011). Vertical

transmission involves the passing of a pathogen with milt or eggs, resulting in infection among offspring.

Pathogens can also be spread by a third host or vector. Vectors can include other parasites, fish,

piscivorous animals or inanimate objects such as clothing, vessels or equipment.

Disease transmission within culture systems is a primary concern of operators and as a consequence

of monitoring and screening, a far greater knowledge base relating to disease causing organisms and

their transmission is available relating to cultured stocks rather than wild stocks. As a result of the lack

of empirical data relating to diseases specific to wild stocks, it has been difficult to partition population

effects in wild-stocks caused by diseases from those caused by other processes (ICES 2010).

Ireland enjoys a high health status (Category 1) in relation to the fish/shellfish on farms, in rivers and

lakes and remains free of many diseases that occur in other countries (www.fishhealth.ie). In Ireland,

there are programmes in place that govern the moment of (fish and shellfish) stock for on-growing

among sites. These movement controls are supported by a risk-based fish health surveillance

programme which is operated on a nationwide basis by the Marine Institute, in co-operation with private

veterinary practitioners. Ireland is currently free of the following salmonid diseases covered by (Council

Directive 2006/88/EC):

1. Infectious Salmon Anaemia (ISA)

2. Viral Haemorrhagic Septicaemia (VHS)

3. Infectious Haematopoetic Necrosis (IHN)

4. Gyrodactylosis

Apart from the diseases listed under EU legislation, routine tests are carried out for other diseases

found in marine salmonids in Ireland e.g. Pancreas Disease (PD), Infectious Pancreatic Necrosis (IPN),

Furunculosis etc. Such diseases are present in Ireland and whilst their control is not covered by

legislation, all finfish farmers in the country have agreed to comply with the parameters of a Code of

Practice and Fish Health Handbook, jointly agreed between the Marine Institute and the Irish Farmers

Association (IFA). These documents cover all aspects of disease prevention and control on Irish fish

farms with the twin objectives of minimising disease outbreaks and of dealing with them in a timely and

responsible fashion, should they arise. The net outcome should be a decrease in mortality rates on fish

farms and a corresponding decrease in potential pathogen transfer to wild stocks. Ensuring the ongoing

good health of farmed stocks and the regular monitoring of environmental conditions will also help to

minimise the disease impacts which may be caused by infection from wild stocks in the vicinity of the

cages.

Disease Management: Council Directive 2006/88/EC on animal health requirements for aquaculture

animals and products thereof, and on the prevention and control of certain diseases in aquatic animals

form the legislative basis that governs the monitoring and management of disease outbreaks in

mariculture operations in Ireland. For diseases not listed in this Directive, a Code of Practice and Fish

Health Handbook has been developed jointly by the State and industry with the primary objectives of

disease prevention and control.

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32006L0088:EN:NOT

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32006L0088:EN:NOT

41

The adoption of chemotherapeutants and some vaccination programmes have assisted in reducing the

abundance and spread of many pathogens. In addition, the principles outlined in the Fish Health

Handbook mentioned above such as improved biosecurity practices on farms, fallowing sites to break

transmission cycles, disease testing of fish prior to transfer, single year class stocking, coordinating

treatments and harvesting within embayments etc have mitigated the transmission of pathogenic

organisms.

In summary, it is clear that a number of broad factors govern the transfer of diseases between

susceptible organisms. While statistical correlations have been demonstrated in terms of abundance of

cultured fish and disease occurrence in wild fishes, extreme caution must apply in terms of applying

causality. It is important to note that the only way to determine the link between disease outbreaks in

aquaculture installations and detection in wild fish is to empirically measure or observe pathogen

transfer. Furthermore, when a risk presents, it not clear if the impact on the wild fish is expressed at the

individual and/or population level. While certain effects have been demonstrated at the level of

individuals, research has not yet clearly identified or quantified these links at the population level.

Disease management programmes operated on a statutory basis by the State and on a voluntary basis

by industry via Codes of Practice, assist in ensuring that pathogen transfer both to and from farmed fish

is kept to a minimum.

Parasites: Sea lice are a group of parasitic copepods found on fish worldwide. There are two species

of sea lice commonly found on cultured salmonids in marine conditions around the coast of Ireland,

Caligus elongatus Nordmann, which infests over eighty different species of marine fish, and

Lepeophtheirus salmonis Krøyer (the salmon louse), which infests only salmon, trout and closely related

salmonid species. L. salmonis, the salmon louse, is the more serious parasite on salmon, both in terms

of its prevalence and effects. It has been reported as a common ecto-parasite of both wild and farmed

salmon at sea.

Returning wild salmon have been found to carry an average of 10 or more adult egg bearing females

on their return to the Irish coastline (Copley et al., 2005; Jackson et al., 2013a) from their feeding

grounds in the Atlantic. Having evolved their relationship with salmon and trout over many millennia,

the parasite is well adapted to target its host species and it is ubiquitous to all the coastal waters around

Ireland and indeed throughout the range of the Atlantic salmon (Jackson et al., 2013b).

Salmon, whether wild or cultured, go to sea from fresh water free of sea lice and only pick up the

infestation after they enter the marine phase of their lives. Sea lice infestations can inflict damage to

their hosts through their feeding activity on the outside of the host's body by affecting the integrity of the

fish’s epithelium, which impairs its osmoregulatory ability and leaves the fish open to secondary

infections. In extreme cases this can lead to a reduced growth rate and an increased morbidity in

affected individuals.

Marine finfish farms are perceived by certain sectors to be problematic because of the proximity of some

operations to river mouths and a concern over the possible impact on wild migratory salmonid fisheries

through infestation with sea lice.

42

The studies on the impacts of lice infestation on smolts (Jackson et al. 2011 & Jackson et al. 2013)

suggest that sea lice induced mortality on outwardly migrating smolts is likely a minor and irregular

component of marine mortality in the stocks studied and therefore, is unlikely to be a significant factor

influencing conservation status of salmon stocks in Clew Bay. This conclusion is further supported by

the finding of no correlation between the presence of aquaculture and the performance of adjacent wild

salmon stocks.

Parasite Management: Based on the evidence from targeted studies, the information collected as part

of the National Sea Lice Monitoring and Control Programme, scientific reports published by the Marine

Institute, and in-line with external advice, it is concluded that there is a robust and effective management

programme in place in Ireland to control sea lice infestation on farmed fish. Furthermore, there is no

empirical evidence to support the suggestion that the fisheries are being adversely affected by unusual

levels of sea lice infestation, whether of farmed origin or from other sources.

6.2 Fisheries

The fishing activities cause physical disturbance to habitats through the use of various fishing gears,

targeted extraction of fish and shellfish and potential by-catch of designated species. The degree to

which habitats are disturbed by fishing depend on the scale, intensity and frequency of fishing activity

and the type of fishing gear used relative to the sensitivity of the receiving habitat. A number of fishing

gears used in Clew Bay have direct contact with the seabed and can therefore impact epi-benthic

communities and in some cases, where the gear penetrates the sediment, can disturb in-faunal biota

as well. Designated species, such as harbour seal and otter can become entangled in static gears, such

as tangle nets, gill nets and trammel nets and a lesser risk of by-catch in towed demersal and pelagic

gears. All fisheries involve the extraction of fish biomass including both the target species and other

species caught as by-catch which potentially disturbs the ecology of the site and its designated features

43

Table 5: Potential indicative environmental pressures of aquaculture activities within the qualifying interests (Mudflats and sandflats not covered

by seawater at low tide (1140) and Large Shallow Inlets and Bays (1160)) of Clew Bay Complex SAC.

METIER/

ACTIVITY

PRESSURE CATEGORY

PRESSURE POTENTIAL EFFECTS EQUIPMENT DURATION

(DAYS) TIME OF

YEAR

FACTORS CONSTRAINING THE ACTIVITY

Aquaculture

Rope Mussel

and other

suspended

Culture

Methods

Physical Current

alteration

Baffling effect resulting in a slowing of currents and

increasing deposition onto seabed changing

sedimentary composition

Floats, longlines, continuous ropes

(New Zealand system) and

droppers

365 All year Location (sheltered location for year round activity)

Biological Organic

enrichment

Faecal and pseudofaecal deposition on seabed

potentially altering community composition.

Drop-off of culture species.

Shading

Prevention of light penetration to seabed

potentially impacting light sensitive species

Fouling

Increased secondary production on structures

and culture species. Increased nekton

production

44

METIER/

ACTIVITY

PRESSURE CATEGORY


(DAYS) TIME OF

YEAR


Seston filtration

Alteration of phytoplankton and

zooplankton communities and potential impact on

carrying capacity

Nutrient

exchange

Changes in ammonium and Dissolved inorganic

nitrogen resulting in increased primary

production. Nitrogen (N2) removal at harvest.

Alien species

Introduction of non-native species with culture

organism transported into the site

Intertidal

Oyster

Culture

Physical Current

alteration

Structures may alter the current regime and resulting increased

deposition of fines or scouring.

Trestles and bags and service equipment

365 All year At low tide only

Surface

disturbance

Ancillary activities at sites, e.g. servicing,

transport increase the risk of sediment

compaction resulting in sediment changes and associated community

changes.

45

METIER/

ACTIVITY

PRESSURE CATEGORY


(DAYS) TIME OF

YEAR


Shading

Prevention of light penetration to seabed

potentially impacting light sensitive species

Biological Non-native

species introduction

Potential for non-native species (C. gigas) to

reproduce and proliferate in SAC. Potential for alien

species to be included with culture stock (hitch-

hikers).

Disease risk

In event of epizootic the ability to manage disease in uncontained subtidal oyster populations is

compromised.

Organic

enrichment

Fecal and pseudofecal deposition on seabed

potentially altering community composition

Subtidal

Oyster/Muss

el culture

Physical Surface

disturbance

Abrasion at the sediment surface and redistribution

of sediment

Oyster dredge Once quarterly

Seasonal Weather for site access. Size of

oysters and market constraints

Shallow

disturbance Sub-surface disturbance

to 25mm

46

METIER/

ACTIVITY

PRESSURE CATEGORY


(DAYS) TIME OF

YEAR


Biological Monoculture

Habitat dominated by single species and

transformation of infaunal dominated community to

epifaunal dominated community.

By-catch mortality

Mortality of organisms captured or disturbed during the harvest or process, damage to

structural fauna of reefs

Non-native

species introduction

Potential for non-native species (C. gigas) to

reproduce and proliferate in SAC (oysters only).

Potential for alien species to be included with culture stock (hitch-hikers) (mussel and

oysters).

Disease risk

In event of epizootic the ability to manage disease in uncontained subtidal

oyster populations would likely be compromised. The risk introduction of

disease causing organisms by introducing seed originating from the ‘wild’ in other jurisdictions

47

METIER/

ACTIVITY

PRESSURE CATEGORY


(DAYS) TIME OF

YEAR


Nutrient

exchange

Increased primary production. N2 removal at harvest or denitrification

at sediment surface.

Salmon Biological Nutrient exchange

Increased primary production. N2 removal at harvest or denitrification at sediment surface.

365 Fallow periods

when no fish in the cages in the water.

Organic enrichment

Fecal and waste food on seabed potentially altering community composition

365

Disease risk Management of parasites and diseases in finfish culture is an ongoing challenge to culturist.

365

48

Aquaculture and Harbour Seal Interactions: In relation to Harbour seals (Phoca vitulina), less

information is available on the potential interactions between the species and the activities in question

(see NRC 2009). There has been no targeted research conducted in similar ecosystems that has

directly assessed the impact of this type of aquaculture on harbor seals or indeed any other seal

populations. There has, however, been considerable research on short-term responses of harbor seals

to disturbance from other sources, and these can be used to inform assessments the potential impacts

of disturbance from aquaculture activities currently underway and proposed in Clew Bay Complex SAC.

These disturbance studies have focused on impacts upon groups of seals that are already ashore at

haul-out sites. Sources of potential disturbance have varied widely, and include people and dogs (Allen

et al., 1984; Brasseur & Fedak, 2003), recreational boaters (Johnson & Acevedo-Gutierrez, 2007; Lelli

& Harris, 2001; Lewis & Mathews, 2000), commercial shipping (Jansen et al., 2006), industrial activity

(Seuront & Prinzivalli, 2005) and aircraft (Perry et al., 2002). A harbor seal’s response to disturbance

may vary from an increase in alertness, movement towards the water, to actual entering into the water,

i.e. flushing (Allen et al., 1984) and is typically governed by the location and nature of the disturbance

activity. For example, kayaks may elicit a stronger response than power boats (Lewis & Mathews, 2000;

Suryan & Harvey, 1999), and stationary boats have been shown to elicit a stronger response than boats

moving along a predictable route (Johnson & Acevedo-Gutierrez, 2007). Furthermore, the mean

distance at which seals are flushed into the water by small boats and people ranges between 80m and

530m, with some disturbances recorded at distances of over 1000m. In certain areas, these empirical

studies have been used to inform management actions in marine protected areas, for example where

a 1.5km buffer is set around harbor seal haul-out sites in the Dutch Wadden Sea to exclude recreational

disturbance (Brasseur & Fedak, 2003).

Displacement from areas may also result from disturbances attributable to the activities of mariculture

workers (Becker et al., 2009; 2011). This disturbance may be caused directly by the presence of

workers on intertidal areas. However, while disturbance from shellfish culture operations have been

observed to influence the distribution of seal within a sheltered embayment, no inference was made on

the effect on broader population characteristics of harbour seals from this study (Becker 2011).

Potential interactions between shellfish culture and marine mammals are broadly summarized in Table

6. It should be noted that direct demonstrations of these impacts are rare, and in most cases, potential

effects are therefore predicted from the best existing information (NRC, 2010). Furthermore, none of

the studies published to explore impacts on marine mammals and in particular Harbour Seals, were

specifically designed to detect ecological impacts on this species (NRC 2009; Becker et al., 2009,

2011). Even where studies have been carried out around shellfish farms, uncertainty over spatial and

temporal variation in both the location of structures (Watson-Capps and Mann, 2005) and levels of

disturbance (Becker et al., 2009; 2011) constrain the conclusions that can be drawn about the impacts

of mariculture on critical life functions such as reproduction and foraging.

Mariculture operations are considered a source of marine litter (Johnson, 2008). Ingestion of marine

litter has also been shown to cause mortality in birds, marine mammals, and marine turtles (Derraik,

2002).

49

Mariculture structures can provide shelter, roost, or haul-out sites for birds and seals (Roycroft et al.,

2004). This is unlikely to have negative effects on bird or seal populations, but it may increase the

likelihood that these species cause faecal contamination of mollusc beds.

Seal interactions with marine finfish cages have been described (Aquaculture Stewardship Council,

2012). The seals (as predators) are attracted to the structures and their contents and have been known

to tear netting in attempts to acquire prey items (i.e. cultured finfish). While a risk of entanglement in

netting may present, it is not considered likely and the greatest risk is the escape of stocked fishes. In

order to mitigate this risk, operators have resorted to the use of deterrent devices (Acoustic or

Harassment) which have variable results based upon the location, extent of use and mammals targeted.

However, deterrent devices are now considered detrimental to seals and alternative management

actions are advised (Nelson 2004; Aquaculture Stewardship Council 2012). Therefore, careful stock

management (density control, regular removal of mortalities from cages), use of seal blinds and

appropriate net tensioning are all considered suitable methods to minimise negative interactions

between seals and finfish culture. Lethal actions to remove seals are only allowed under licence the

criteria which are determined by NPWS (Section 42 of the Wildlife Act, 1976 (as amended).

In the Clew Bay Complex SAC it would appear that the overall Harbour Seal numbers (population) has

been stable or increasing between 2003 and 2012 (NPWS data) coincident with static levels of

mariculture production. While no definitive conclusions can be drawn regarding the population status

of harbour seals in Clew Bay and more widely around Ireland, based upon survey reports from 2009-

2011 (as no baseline reference values are provided), it would appear that the levels both regionally and

nationally are stable or possibly increasing (see Figure 2 in NPWS 2012 -

http://npws.ie/marine/marinereports/Harbour%20Seal_NPWS%20pilot%20monitoring%20study%202

011_Final%20doc.pdf).

50

Table 6: Potential interactions between aquaculture activities and the Annex II species Harbour Seal (Phoca vitulina) within the Clew Bay SAC.

CULTURE METHOD

PRESSURE CATEGORY


(DAYS)

TIME OF

YEAR

FACTORS CONSTRAINING THE ACTIVITY/EFFECTS

All Aquaculture

Methods Physical

Habitat Exclusion

Structures may result in a barrier to movement of seals.

Net pens, Bags and trestles

365 All year Spatial extent and location of structures used for culture.

Disturbance

Ancillary activities at sites increase the risk of disturbance to seals at haul out sites (resting, breeding and/or moulting) or in the water.

Site services, human, boat and vehicular traffic

365 All year

Seasonal levels of activity relating to seeding, grading, and harvesting. Peak activities do no coincide with more sensitive periods for seals (i.e. pupping and moulting)

Entanglement

Entanglement of seals from ropes or material used on structures or during operation of farms

Trestles, bags,ropes and/or nets used in day to day

365 All year Farm management practices

Ingestion Ingestion of waste material used on farm

Ties used to secure bags and secure bags to trestle

365 All year Farm management practices

Deterrent Methods

Seals interfering with cages will result in deterrent actions, e.g. use of Acoustic deterrent or harassment Devices. If all non lethal avenues fail then lethal methods may be employed (under licence).

ADDs and lethal devices (shooting)

365 Fallow periods no fish on-site

51

7 Screening of Aquaculture Activities

A screening assessment is an initial evaluation of the possible impacts that activities may have on the

qualifying interests. The screening, is a filter, which may lead to exclusion of certain activities or

qualifying interests from appropriate assessment proper, thereby simplifying the assessments, if this

can be justified unambiguously using limited and clear cut criteria. Screening is a conservative filter

that minimises the risk of false negatives.

In this assessment screening of the qualifying interests against the proposed activities is based primarily

on spatial overlap i.e. if the qualifying interests overlap spatially with the proposed activities then

significant impacts due to these activities on the conservation objectives for the qualifying interests is

not discounted (not screened out) except where there is absolute and clear rationale for doing so.

Where there is relevant spatial overlap full assessment is warranted. Likewise if there is no spatial

overlap and no obvious interaction is likely to occur, then the possibility of significant impact is

discounted and further assessment of possible effects is deemed not to be necessary. Table 3 provides

spatial overlap extent between designated habitat features and aquaculture activities within the

qualifying interests of Clew Bay Complex SAC.

7.1 Aquaculture Activity Screening

- Table 3 highlights the spatial overlap between (existing and proposed) aquaculture activities and

both habitat features (i.e. Large Shallow Inlet and Bay and Mudflat and Sandflats not covered by

seawater at low tide).

- Tables 7 and 8 provides an overview of overlap of aquaculture activities and specific community

types (identified from Conservation objectives) within the broad habitat features 1140 and 1160,

respectively.

- A single activity, (i.e. the terrestrial fish hatchery operation) on the shores of Lough Furnace (Coastal

Lagoon) is also excluded further from this analysis as there is little or no spatial overlap with

conservation feature (Coastal Lagoon) and the licenced discharge (treated effluent) is unlikely to

contribute to deterioration of any of the target attributes listed in NPWS 2011.

Where the overlap between an aquaculture activity and a feature is zero it is screened out and not

considered further. Therefore, the following six habitats and one species are excluded from further

consideration in this assessment. ;

- 1013 Geyer's whorl snail Vertigo geyeri

- 1210 Annual vegetation of drift lines

- 1220 Perennial vegetation of stony banks

- 1330 Atlantic salt meadows (Glauco‐Puccinellietalia maritimae)

- 2110 Embryonic shifting dunes

52

- 2120 Shifting dunes along the shoreline with Ammophila arenaria ("white dunes")

- 1150 Coastal Lagoons

Furthermore, of the seven community types (see Table 1) listed under the two habitat features (1140

and 1160) two (Zostera dominated communities and Mearl dominated Commuities) have no spatial

overlap between them and any aquaculture activities. For other community types, when overlap was

observed it was estimated in a GIS application and calculated on the basis of coverage of specific

activity (representing different pressure types), licence status (licenced or application) intersecting with

designated conservation features and/or sub-features (community types). The values represented also

summarise the total coverage if applications were to supplant existing licences in order to facilitate

restructuring or expansion of existing sites (Table 8). On this basis, the community type Zostera

dominated community and Mearl dominated Commuities are excluded from further analysis of

aquaculture interactions.

53

Table 7: Habitat utilisation i.e. spatial overlap in hectares and percentage (given in parentheses) of Aquaculture activity over community

types within the qualifying interest 1140 - Mudflat and sandflats not covered by seawater at low tide of Clew Bay Complex SAC. (Spatial data

based on licence database provided by DAFM. Habitat data provided in NPWS 2011 – supporting docs marine and coastal)

1140 - Mudflats and sandflats not covered by seawater at low tide

Culture Type Location Method Status

Intertidal sandy mud with Tubificoides

benedii and Pygospio elegans

community complex (788ha)

Sandy mud with polychaetes and

bivalves community complex (445ha)

Fine sand dominated by Nephtys cirrosa

community (44ha)

Oysters (Crassostrea gigas) in bags & trestles.

Intertidal Intensive Licenced 13.56

(1.72%)

41.76

(9.38%)

2.38

(5.6%)


Intertidal Intensive Applications - 6.27

(1.4%) -

Vehicular traffic in Intertidal areas.

Intertidal - N/A 1.25

(0.16%)

5.43

(1.22%) -

Corrected Totals* 14.81

(1.88)

53.46

(12.01)

2.38

(5.6%)


54

Table 8: Habitat utilisation i.e. spatial overlap in hectares and percentage (given in parentheses) by Aquaculture activity over specific

community types within the qualifying interest 1160 – Large shallow inlets and bays of Clew Bay Complex SAC based on licence database

provided by DAFM. Habitat data provided in NPWS 2011 – supporting docs marine and coastal)

Large Shallow Inlet and Bay (1160)


Intertidal sandy mud

with Tubificoides benedii and Pygospio elegans


Sandy mud with

polychaetes and bivalves community

complex (5,791ha)

Fine sand dominated by

Nephtys cirrosa

community (296ha)

Reef (2,687ha)

Shingle (146ha)

Maerl (288ha)


Intertidal Intensive Licenced

13.58

(1.72%)

139.62

(2.4%)

7.32

(2.47%)

4.15

(0.15%) - -


Intertidal Intensive Application - 22.4

(0.39%) -

0.17

(<0.001) - -

Oysters (Crassostrea gigas) on seabed

Subtidal Extensive Licenced 5

(0.09%)

Mussel (Mytilus edulis) on ropes

Subtidal Intensive Licenced - 64.55

(1.1%) - - - -


Subtidal Intensive Application - 10.35

(0.18%) - - - -

55

Large Shallow Inlet and Bay (1160)


Intertidal sandy mud

with Tubificoides benedii and Pygospio elegans


Sandy mud with

polychaetes and bivalves community

complex (5,791ha)

Fine sand dominated by

Nephtys cirrosa

community (296ha)

Reef (2,687ha)

Shingle (146ha)

Maerl (288ha)

Abalone Subtidal Intensive Application - 2.64

(0.05%) - - - -

Scallop Subtidal Extensive - 4.00

(0.1) -

-

- -

Lobster Subtidal Intensive Licenced - 1.0

(0.02%) - - - -

Salmon (Salmo salar) in net pens

Subtidal Intensive Licenced - 11.29

(0.20) -

4.67

(0.17) - -


Intertidal Intensive N/A 1.14

(0.14%) 6.1

(0.11)

1.3 (0.04%)

0.14 (0.10)

-

Corrected Totals* 14.72

(1.87%)

256.60*

(4.43%)

7.32

(2.47%)

10.29

(0.39%)

0.14 (0.10)

-


56

8 Assessment of Aquaculture Activities

8.1 Determining significance

The significance of the possible effects of the proposed activities on habitats, as outlined in the Natura

Impact statement (Section 6) and subsequent screening exercise (Section 7), is determined here in the

assessment. The significance of effects is determined on the basis of Conservation Objective guidance

for constituent habitats and species (Figure 1-3 and NPWS 2011a, b).

Habitats and species that are key contributors to biodiversity and which are sensitive to disturbance

should be afforded a high degree of protection i.e. thresholds for impact on these habitats is low and

any significant anthropogenic disturbance should be avoided. In Clew Bay these habitats include:

- 1160 Zostera - 1160 Maerl

Within the Clew Bay SAC the qualifying habitats/species considered subject to potential disturbance

and therefore, carried further in this assessment are:

- 1140 Mudflats and sandflats not covered by seawater at low tide - 1160 Large shallow inlets and bays - 1355 Otter - Lutra lutra - 1365 Common (Harbour) seal - Phoca vitulina - 1106 Salmon - Salmo salar – migrating salmon through Clew Bay Complex from

adjacent SACs from Section 4.4.

For broad habitats and sedimentary communities (Figures 1 and 2) significance of impact is determined

in relation to, first and foremost, spatial overlap (see Section 7; Figure 16). Subsequent disturbance

and the persistence of disturbance are considered as follows:

1. The degree to which the activity will disturb the qualifying interest. By disturb is meant

change in the characterising species, as listed in the Conservation Objective guidance

(NPWS 2011b) for constituent communities. The likelihood of change depends on the

sensitivity of the characterising species to the activities in question. Sensitivity results from

a combination of intolerance to the activity and/or recoverability from the effects of the

activity (see Section 8.2 below).

2. The persistence of the disturbance in relation to the intolerance of the community. If the

activities are persistent (high frequency, high intensity) and the receiving community has a

high intolerance to the activity (i.e. the characterising species of the communities are

sensitive and consequently impacted) then such communities could be said to be

persistently disturbed.

3. The area of communities or proportion of populations disturbed. In the case of community

disturbance (continuous or ongoing) of more than 15% of the community area it is deemed

to be significant. This threshold does not apply to sensitive habitats as listed above (Zostera,

Maerl, Reef) where any physical disturbance should generally be avoided

57

Effects will be deemed to be significant when cumulatively they lead to long term change (persistent

disturbance) in broad habitat/features (or constituent communities) resulting in an impact greater than

15% of the area.

Figure 16: Determination of significant effects on community distribution, structure and function

for sedimentary habitats (following NPWS 2011b).

In relation to designated species (Harbour Seal, otter) the capacity of the population to maintain itself

in the face of anthropogenic induced disturbance or mortality at the site will need to be taken into

account in relation to the Conservation Objectives (CO’s) on a case by case basis.

8.2 Sensitivity and Assessment Rationale

This assessment used a number of sources of information in assessing the sensitivity of the

characterising species of each community recorded within the benthic habitats of Clew Bay Complex

SAC. The primary source of information is a series of commissioned reviews by the Marine Institute

which identify habitat and species sensitivity to a range of pressures likely to result from aquaculture

and fishery activities (ABPMer 2013a-h). These reviews draw from the broader literature, including the

MarLIN Sensitivity Assessment (Marlin.ac.uk) and the AMBI Sensitivity Scale (Borja et al., 2000) and

58

other primary literature. Sensitivity of a species to a given pressure is the product of the intolerance (the

susceptibility of the species to damage, or death, from an external factor) of the species to the particular

pressure and the time taken for its subsequent recovery (recoverability is the ability to return to a state

close to that which existed before the activity or event caused change). Life history and biological traits

are important determinants of sensitivity of species to pressures from aquaculture.

In the case of species, communities and habitats of conservation interest, the separate components of

sensitivity (intolerance, recoverability) are relevant in relation to the persistence of the pressure:

For persistent pressures i.e. activities that occur frequently and throughout the year recovery

capacity may be of little relevance except for species/habitats that may have extremely rapid

(days/weeks) recovery capacity or whose populations can reproduce and recruit in balance with

population damage caused by aquaculture. In all but these cases and if sensitivity is moderate

or high then the species/habitats may be negatively affected and will exist in a modified state.

Such interactions between aquaculture and species/habitat/community represent persistent

disturbance. They become significantly disturbing if more than 15% of the community is thus

exposed (NPWS 2011).

In the case of episodic pressures i.e. activities that are seasonal or discrete in time both the

intolerance and recovery components of sensitivity are relevant. If sensitivity is high but

recoverability is also high relative to the frequency of application of the pressure then the

species/habitat/community will be in favourable conservation status for at least a proportion of

time.

The sensitivities of the community types (or surrogates) found within the Clew Bay Complex SAC to

pressures similar to those caused by aquaculture (e.g. smothering, organic enrichment and physical

disturbance) are listed, where available, in Table 9. The sensitivities of species which are characteristic

(as listed in the Conservation Objective supporting document) of benthic communities to pressures

similar to those caused by aquaculture (e.g. smothering, organic enrichment and physical disturbance)

are listed, where available, in Table 10. The following guidelines broadly underpin the analysis and

conclusions of the species and habitat sensitivity assessment:

Sensitivity of certain taxonomic groups such as emergent sessile epifauna to physical pressures

is expected to be generally high or moderate because of their form and structure (Roberts et al.

2010). Also high for those with large bodies and with fragile shells/structures, but low for those

with smaller body size. Body size (Bergman and van Santbrink 2000) and fragility are regarded

as indicative of a high intolerance to physical abrasion caused by fishing gears (i.e. dredges).

However, even species with a high intolerance may not be sensitive to the disturbance if their

recovery is rapid once the pressure has ceased.

Sensitivity of certain taxonomic groups to increased sedimentation is expected to be low for

species which live within the sediment, deposit and suspension feeders; and high for those

sensitive to clogging of respiratory or feeding apparatus by silt or fine material.

59

Recoverability of species depends on biological traits (Tillin et al. 2006) such as reproductive

capacity, recruitment rates and generation times. Species with high reproductive capacity, short

generation times, high mobility or dispersal capacity may maintain their populations even when

faced with persistent pressures; but such environments may become dominated by these (r-

selected) species. Slow recovery is correlated with slow growth rates, low fecundity, low and/or

irregular recruitment, limited dispersal capacity and long generation times. Recoverability, as

listed by MarLIN, assumes that the impacting factor has been removed or stopped and the habitat

returned to a state capable of supporting the species or community in question. The recovery

process is complex and therefore the recovery of one species does not signify that the associated

biomass and functioning of the full ecosystem has recovered (Anand & Desrocher, 2004) cited

in Hall et al., 2008).

8.3 Assessment of the effects of aquaculture production on the Conservation Objectives for habitat features in Clew Bay Complex SAC.

Aquaculture pressures on a given habitat are related to vulnerability (spatial overlap or exposure of the

habitat to the equipment/culture organism combined with the sensitivity of the habitat) to the pressures

induced by culture activities. To this end, the location and orientation of structures associated with the

culture organism, the density of culture organisms, the duration of the culture activity and the type of

activity are all important considerations when considering risk of disturbance to habitats and species.

NPWS (2011b) provide lists of species characteristic of benthic communities that are defined in the

Conservation Objectives. The species defined are typical of fine sedimentary habitats as well as where

relevant, intertidal habitats (tolerant of desiccation and physical stress). For the most part, these

intertidal communities are typically impoverished with low numbers of species and overall abundances.

Different species and habitats will have different tolerance to the pressures associated with aquaculture

activities (pressures as discussed in Sections 5 and 6). The constituent communities identified in the

broad Annex 1 feature (i.e., Mudflats and sandflats not covered by seawater at low tide) are:

1. Intertidal sandy mud with Tubificoides benedii and Pygospio elegans community complex

2. Sandy mud with polychaetes and bivalves community complex

3. Fine sand dominated by Nephtys cirrosa community

They are predominantly sandy-muddy habitat types and given they are intertidal and, in parts, estuarine,

can be exposed to a range of physical and hydrodynamic pressures. Table 9 lists the habitats and Table

10 lists the constituent taxa and both provide a commentary of sensitivity to a range of pressures. The

risk scores are derived from a range of sources identified above. The pressures are listed as those

likely to result from the primary activities carried out in Clew Bay Complex SAC, i.e. intertidal oyster

culture in bags on trestles, rope mussel culture, subtidal clam and mussel culture and salmon culture.

While the feature Large shallow inlets and bays includes intertidal communities (considered above),

it is subtidal communities which predominate this feature type. In addition to the communities listed

above, for which there are distinguishing subtidal characteristics,

60

the feature Large Shallow Inlets and Bays also contain the following community types;

Shingle

Reef

The fauna characterising the habitat types listed above are typical of inshore subtidal communities

found in fine sedimentary habitats. They are dominated by polychaete worms and bivalves. The reef

communities are typical of intertidal cobble (and mixed sediment communities) as well as subtidal

communities dominated by large macro algal (kelp) and faunal turf (sponges and hydrozoans). Mearl

dominated communities are considered highly diverse and sensitive habitat types which host a wide

range of taxa. The ‘keystone’ species in each community type (Maerl and Zostera) is considered

important and sensitive in their own right. Shingle is typically found high in the intertidal zone and is

considered a robust and resilient habitat type. Aquaculture activities overlap with all habitat type (with

the exception of Zostera and Mearl) listed above (Tables 7 and 8).

Aquaculture activities in Clew Bay Complex SAC comprises both finfish and shellfish production

methods. Considered in the assessment are intertidal oyster culture (bag and trestle), intertidal clam

on-bottom culture, subtidal (suspended) rope mussel culture, subtidal on-bottom culture of oysters and

Atlantic salmon culture in net pens. Other culture methods considered are abalone, scallop and lobster

culture.

This aquaculture type overlaps six different community types found within the qualifying interest of the

SAC. Tables 12 and 13 below identify the likely interactions between the relevant aquaculture activities

and the two broad habitat features (1140 and 1160) and their constituent community types, with a broad

conclusion and justification on whether the activity is considered disturbing to the feature in question. It

must be noted that the sequence of distinguishing disturbance is as highlighted above, whereby

activities with spatial overlap on habitat features are assessed further for their ability to cause

persistence disturbance on the habitat. If persistence disturbance is likely then the spatial extent of the

overlap is considered further. If the proportion of the overlap exceeds a threshold of 15% disturbance

of the habitat then any further licencing should be informed by interdepartmental review and

consultation (NPWS 2011b).

Other Considerations: The presence of the invasive species, Didemnum vexillum, does have the

potential to impact on the conservation features of the site. To date, Didemnum has been confirmed to

occur in the southern portion of the bay and a link to aquaculture structures has been established. The

risk posed by this alien species cannot be discounted.

61

Table 9: Matrix showing the characterising habitats sensitivity scores x pressure categories for habitats in Clew Bay Complex SAC (ABPMer 2013a-h).

Pressure Type Physical Damage Change in Habitat Quality Biological Pressures Chemical Pollution Physical

Pressures

Community Type (EUNIS code)

Surfa

ce D

istu

rbance

Sha

llow

Dis

turb

ance

Deep D

istu

rbance

Tra

mplin

g-A

ccess b

y fo

ot

Tra

mplin

g-A

ccess b

y v

ehic

le

Extra

ctio

n

Silta

tion

(add

ition o

f fine s

edim

ents

,

pseudo

faeces, fis

h fo

od)

Sm

oth

erin

g (a

dd

ition o

f mate

rials

bio

log

ical o

r non

-bio

log

ical to

the

surfa

ce)

Chan

ges to

se

dim

en

t com

positio

n-

incre

ased

coars

eness

Chan

ges to

se

dim

en

t com

positio

n-

incre

ased

fine s

ed

iment p

roportio

n

Chan

ges to

wate

r flow

Incre

ase in

turb

idity

/suspe

nded

sedim

ent

Decre

ase in

turb

idity

/suspe

nded

sedim

ent

Org

anic

enric

hm

ent-w

ate

r colu

mn

Org

anic

enric

hm

ent o

f sed

iments

-sedim

enta

tion

Incre

ased re

mova

l of p

rima

ry

pro

ductio

n-p

hyto

pla

nkto

n

Decre

ase in

oxyge

n le

vels

-

sedim

ent

Decre

ase in

oxyge

n le

vels

-wate

r

colu

mn

Intro

ductio

n o

f non

-nativ

e s

pecie

s

Rem

ova

l of T

arg

et S

pecie

s

Rem

ova

l of N

on

-targ

et s

pe

cie

s

Ecosyste

m S

erv

ices-L

oss o

f

bio

mass

Intro

ductio

n o

f antifo

ula

nts

Intro

ductio

n o

f med

icin

es

Intro

ductio

n o

f hydro

carb

on

s

Pre

ventio

n o

f light re

achin

g

seabed

/fea

ture

s

Sandy mud with polychaetes and bivalves community complex (Intertidal A2.24)

NS (***)

L (*)

L (***)

NS (*)

L (*)

L-M (*)

L-M (*)

L-M (*)

L-M (*)

NS (*)

L-M (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

L (*)

L (*)

H (***)

NS (*)

NS (*)

NA NS (*)

NS (*)

L (*)

NS (*)

Fine sand dominated by Nephtys cirrosa community (Intertidal and subtidal) (A5.23)

NS (***)

L (*)

L (***)

NE NE L-M (*)

L-M (*)

L-M (*)

M-L (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

L (***)

NS (*)

L (*)

L (*)

H (***)

NS (*)

NS (*)

NA NS (*)

NS (*)

L (*)

NS (*)

Sandy mud with polychaetes and bivalves community complex (Subtidal A5.33)

NS (*)

L (*)

L (*)

NE NE L-M (*)

L (*)

L-M (*)

L-M (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

L (*)

NS (*)

L (*)

L (*) H (*) NS (*)

NS (*)

NA NS (*)

NS (*)

L (*)

NS (*)

Intertidal marine shores (A2.33)

NS-L (*)

L (*)

L (*)

NS (*)

L (*) L-M (*)

NS (*)

M-H (*)

L-M (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

L (*)

L (*) H (*) NS (*)

NS (*)

NA NS (*)

NS (*)

L (*)

NS (*)

Intertidal sandy mud with Tubificoides benedii and Pygospio elegans community complex - (A2.23)

NS (*)

L (*)

L (*)

NS (*)

L-NS (*)

L-M (*)

L-M (*)

L-M (*)

L-M (*)

M (*)

L-M (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

L-NS (*)

L-NS (*)

NS (***)

NS (*)

NS (*)

NA NS (*)

NS (*)

L (*)

NS (*)

Maerl (A5.51) H

(***) H-VH (***)

H (***)

H (***)

H (***)

H-VH (***)

H-VH (***)

H-VH (***)

NS (*)

NS (*)

NS (*)

H (*)

NS (*)

H (*)

H (***)

NS (*)

H (**)

H (**)

H (***)

VH (***)

NS (*)

NE NE NE NE

VH (*)

62

.

Table 10: Matrix showing the characterising species sensitivity scores x pressure categories for habitats in Clew Bay Complex SAC (ABPMer 2013a-h). Table 11 provides the code for the various categorisation of sensitivity and

confidence

Pressure Type Physical Damage Change in Habitat Quality Biological Pressures Chemical Pollution Physical

Pressures

Pressure

Surfa

ce D

istu

rbance

Sha

llow

Dis

turb

ance

Deep D

istu

rbance

Tra

mplin

g-A

ccess b

y fo

ot

Tra

mplin

g-A

ccess b

y v

ehic

le

Extra

ctio

n

Silta

tion

Sm

oth

erin

g (a

dd

ition o

f mate

rials

bio

log

ical o

r non

-bio

log

ical to

the

surfa

ce)

Chan

ges to

se

dim

en

t com

positio

n- in

cre

ased

coars

eness

Chan

ges to

se

dim

en

t com

positio

n- in

cre

ase

d fin

e

sedim

ent p

roportio

n

Chan

ges to

wate

r flow

Incre

ase in

turb

idity

/suspe

nded

sedim

ent

Decre

ase in

turb

idity

/suspe

nded

sedim

ent

Org

anic

enric

hm

ent-w

ate

r colu

mn

Org

anic

enric

hm

ent o

f sed

iments

-

sedim

enta

tion

Incre

ased re

mova

l of p

rima

ry

pro

ductio

n-p

hyto

pla

nkto

n

Decre

ase in

oxyge

n le

vels

-

sedim

ent

Decre

ase in

oxyge

n le

vels

-wate

r colu

mn

Intro

ductio

n o

f non

-nativ

e s

pecie

s

Rem

ova

l of T

arg

et S

pecie

s

Rem

ova

l of N

on

-targ

et s

pe

cie

s

Intro

ductio

n o

f antifo

ula

nts

Intro

ductio

n o

f med

icin

es

Intro

ductio

n o

f hydro

carb

on

s

Pre

ventio

n o

f light re

achin

g

seabed

/fea

ture

s

Abra alba L (*) L (***) L (*) L (*) L (*) M (*) NS (***)

M (*) L (*) NS (*) NS (*)

L (*)

L (*) NS (*)

NS (*)

NS (*)

L (***) L-M (***)

L-M (*)

NS (*)

NS (*)

NS (***)

NEv L

(***) NS (*)

Bathyporeia spp. NS (*)

L (***) L (***) NS (*) L (*) L-M (*)

L (***)

L-M (*) L-M (*)

L-M (*) NS (*)

NS (*)

NS (*)

L-M (*)

L-M (*)

NS (*)

L-M (***)

L-M (***)

L-M (*)

NS (*)

NS (*)

NS (*)

NEv NEv NS (*)

Capitella spp. L (*) L (**) L (**) L (***) L (*) L (*) L (*) NS (*) NS (*) NS (***)

NS (*)

NS (*)

NS (*)

NS (***)

NS (***)

NS (*)

L (***) L (***) NS (*)

NS (*)

NS (*)

NS (***)

L (***)

NS (***)

NS (*)

Cerastoderma edule

L (*) L-M (*) L-M (***) L-M (***) L-M (*) L-H (*)

L (***)

L-M (*) L-H (*) NS (*) L (*) NS (*)

NS (*)

NS (*)

NS (**)

L-NS (*)

L-M (*)

L-M (*)

M (*) M (*)

NS (*)

NS (*)

NEv L-M (*)

NS (*)

Lanice conchilega NS (*)

NS-L (***)

NS-L (***) NS (*) NS-L (*) M-H (*)

NS (*)

M-H (*) NS (*) NS (***)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

M (*) M (*) M-H (*)

NS (*)

NS (*)

NS (*)

NEv L

(***) NS (*)

Nephtys cirrosa NS (*)

L (***) L (***) NS (*) L (*) L (*) NS (***)

NS (*) L (*) NS (*) L (*) NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*) NS (*) M (*) M (*)

NS (*)

NS (*)

NEv NEv NS (*)

Pygospio elegans L (*) L (**) M (***) L (*) L (*) L-M (*)

L (***)

L-M (***) L-M (*)

NS (**) L-M (*)

NS (*)

NS (*)

NS (*)

NS (***)

NS (*)

L (**) L (**) M (*) NS (*)

NS (*)

NS (*)

NEv NEv NS (*)

Scoloplos armiger NS (*)

L (*) L-M (*) NS (*) L (*) H (*) NS (*)

NS (*) NS (*) NS (*) NS (*)

NS (*)

NS (*)

NS (***)

NS (***)

NS (*)

M (***)

M (***)

M (*) M

(**) NS (*)

NS (*)

NEv NEv NS (*)

Tubificoides spp. NS (*)

NS (*) L (**) L (*) L (*) M (*) NS (*)

L (*) NS (*) NS (*) NS (***)

NS (*)

NS (*)

NS (***)

NS (***)

NS (*)

NS (***)

NS (***)

NS (*)

NS (*)

NS (*)

NS (**)

NEv NEv NS (**)

Hydrobia ulvae L-NS

(*) L (***) L (*) L-NS (*) L-NS (*) M (*)

NS (***)

L (*) NS (*) NS (*) NS (*)

NS (*)

NS (*)

NS (*)

NS (***)

NS (*)

L (*) L (*) L (*) NS (*)

NS (*)

NEv NEv M (*) NS (*)

Corophium volutator L

(***) L (***) L (***) L (*) L (*) L (*)

L (***)

L (***) M (*) NS (*) NS (*)

NS (*)

NS (*)

NS (***)

NS (***)

NS (*)

L (***) L (***) Nev NS (*)

NS (*)

NA NEv L

(***) NS (*)

Nematoda NS (***)

NS (***) NS (***) NS (***) NS (*) L (*) NS (*)

NS (***) NS (***)

NS (***)

NS (*)

NS (*)

NS (*)

NS (*)

NS (***)

NS (*)

L (***) L (***) NS (***)

NS (*)

L (*) NS (***)

NEv L

(***) NS (*)

Notomastus sp NS (*)

L (***) L (***) NS (*) L (*) L-M (*)

L (**) L (*) NS (*) NS (*) NS (*)

NS (*)

NS (*)

NS (*)

NS (**)

NS (*)

L (*) L (*) M (*) NS (*)

NS (*)

NS (*)

NEv NS (***)

NS (*)

Melinna palmata NS (***)

NS (***) NS (***) NS (*) NS (*) M (*) L

(***) M (*) NS (*) NS (*)

NS (*)

L (*)

NS (***)

NS (***)

NS (***)

NS (*)

NS (***)

NS (***)

L (*) NS (*)

NS (*)

NS (***)

NEv M

(***) NS (*)

Prionospio spp. NS (*)

NS (***) NS (*) NS (*) NS (*) L (*) L

(***) L (*) NS (*) NS (*)

NS (*)

NS (*)

NS (*)

NS (***)

NS (***)

NS (*)

NS (***)

NS (***)

L (*) NS (*)

NS (*)

NS (***)

NEv NS (***)

NS (*)

Mysella bidentata NS (*)

NS (*) L-M (*) NE NE M (*) NS (*)

NS (*) NS (*) NS (*) NS (*)

NS (*)

NS (*)

NS (**)

NS (**)

NS (*)

NS (*) NS (*) NS (*)

NS (*)

L-M (*)

NS (*)

NEv NA NS (*)

Thyasira flexuosa L (*) L (***) L (*) L (*) L (*) M-H (*)

NS (*)

M-H (*) NS (*) NS (*) NS (*)

NS (*)

NS (*)

NS (*)

NS (***)

NS (*)

M (***)

M (***)

M (*) NS (*)

NS (*)

NS (***)

NEv NS (***)

NS (*)

Angulus sp. (Moerella)

NS (*)

L (*) L (***) NS (*) L (*) M (*) NS (*)

H (*) M-H (*)

NS (*) L-M (*)

L (*)

NS (*)

NS (*)

Nev L-NS

(*) NEv NEv M (*)

NS (*)

NS (*)

NS (*)

NEv NEv NS (*)

63

Table 11: Codes of sensitivity and confidence applying to species and pressure interactions

presented in Tables 10 and 11.

Species x Pressure Interaction Codes for Tables 9 and 10

NA Not Assessed

Nev No Evidence

NE Not Exposed

NS Not Sensitive

L Low

M Medium

H High

VH Very High

* Low confidence

** Medium confidence

*** High Confidence

In summary, it is concluded that, the aquaculture activities (existing and proposed) individually and in-

combination do not pose a risk of significant disturbance to the conservation features for habitats in

Clew Bay based primarily upon the spatial overlap and sensitivity analysis (Tables 12 and 13).

The risk posed by the presence of the alien species, the carpet sea squirt, Didemnum sp., cannot be

discounted.

64

Table 12. Interactions between the relevant aquaculture activities and the habitat feature 1140 constituent communities with a broad conclusion on the nature of the interactions

1140 - Mudflats and sandflats not covered by seawater at low tide

Culture Type Location Method



Fine sand dominated by Nephtys cirrosa community

Oysters (Crassostrea gigas), in bags & trestles.

Intertidal Intensive

Disturbing: No

Justification: This community type considered

tolerant to pressures from activity. The species have

high recoverability and are tolerant. The stock is

confined in bags, is sourced from hatcheries and up to

80% triploid.

Disturbing: No

Justification: The community type is considered

tolerant to pressures from activity. The species have

high recoverability and are tolerant. The stock is

confined in bags, is sourced from hatcheries and up to

80% triploid.

-



Disturbing: Yes

Justification: This community type is likely sensitive

to persistent pressure (compaction) from this activity.

The spatial overlap is 0.16% of this community type.

Disturbing: Yes

Justification: This community and species are likely

sensitive to persistent pressure (compaction) from this

activity. The spatial overlap is 1.22% of this community

type.

-

Cumulative impact Aquaculture

Disturbing: No

Justification: the cumulative pressure of likely

impacting activities is 0.16% on this community type.

Disturbing: No

Justification: the cumulative pressure of likely

impacting activities is 1.22% on this community type.

-

65

Table 13. Interactions between the relevant aquaculture activities and the habitat feature 1160 constituent communities with a broad conclusion on the nature of the interactions.

Large Shallow Inlet and Bay [1160]


Intertidal sandy mud with Tubificoides benedii and

Pygospio elegans community complex

Sandy mud with polychaetes and bivalves

community complex


community Shingle Reef

Oysters (Crassostrea gigas), in bags & trestles.


Disturbing: No

Justification: This community is considered tolerant to pressures from activity. The species have high recoverability and are tolerant. The stock is confined in bags, is sourced from hatcheries and up to 80% triploid.

Disturbing: No


Disturbing: No


-

Disturbing: Yes

Justification: This community is considered sensitive to pressures from activity due to shading and compaction. Activity represents 0.15% of this community type

Oysters (Crassostrea gigas), on the seafloor.

Subtidal Extensive -

Disturbing: Yes

Justification: Harvest method using dredge disturbing to seafloor fauna. All stock cannot be recovered due to uncontained placement on seafloor. If diploid stock is used the risk of successful reproduction is greater than if 3n stock is used. Activity represents 0.09% of this community type.

- - -


Subtidal Intensive -

Disturbing: Yes

Justification: The high density of stock will impact on seafloor due to organic enrichment (faeces and pseudofaeces) and stock drop off. This activity represents 1.28% of this community type.

- - -

Salmon (Salmo salar) in net pens


Disturbing: Yes

Justification: The community type and species would be sensitive to the activity by virtue of persistent organic enrichment on the seafloor. The spatial overlap is 0.20% of this community type.

- -

Disturbing: Yes

Justification: The community type and species would be sensitive to the activity by virtue of persistent organic enrichment on the seafloor. The spatial overlap is 0.17% of this community type.

66

Large Shallow Inlet and Bay [1160]


Intertidal sandy mud with Tubificoides benedii and

Pygospio elegans community complex

Sandy mud with polychaetes and bivalves

community complex


community Shingle Reef

Abalone in contained systems


Disturbing: Yes

Justification: This community type would be sensitive to the activity by virtue of physical disturbance. The spatial overlap is 0.05% of this community type.

- -

Disturbing: No

Justification: This community type is considered tolerant to pressures from activity.

Scallop on seabed Subtidal Extensive -

Disturbing: No

Justification: Given the species to be cultured is native and that harvesting is proposed to be by hand (diving), This community type is not likely be sensitive to the activity.

- -

Disturbing: No

Justification: This community type is considered tolerant to pressures from activity.



Disturbing: Yes

Justification: This community type is likely sensitive to persistent pressure (compaction) from this activity. The spatial overlap is 0.14% of this community type.

Disturbing: Yes

Justification: This community type is likely sensitive to persistent pressure (compaction) from this activity. The spatial overlap is 0.11% of the community type.

-

Disturbing: Yes

Justification: This community type is likely sensitive to persistent pressure (compaction) from this activity. The spatial overlap is 0.10% of the habitat type (<15% threshold).

Disturbing: Yes

Justification: This community type is likely sensitive to persistent pressure (compaction) from this activity. The spatial overlap is 0.04% of this community type.

Cumulative Impact Aquaculture

Disturbing: No

Justification: the cumulative pressure of likely impacting activities is 1.87% on this community type.

Disturbing: No


Disturbing: No

Justification: the cumulative pressure of likely impacting activities is 0% on this community type.

Disturbing: No


Disturbing: No


67

8.4 Assessment of the effects of shellfish production on the Conservation Objectives for Harbour Seal in Clew Bay Complex SAC.

Clew Bay Complex SAC is designated for the Harbour Seal (Phoca vitulina). The distribution of harbour

seal and site use are provided in Figure 3. The conservation objectives for this species are listed in

Table 1 and can be found in detail in NPWS (2011; 2012). While the conservation status of the species

is considered favourable at the site, the interactions between harbour seals and the features and

aquaculture activities carried out in the SAC must be ascertained.

The interactions between aquaculture operations and aquatic mammal species are a function of:

1. The location and type of structures used in the culture operations - is there a risk of

entanglement or physical harm to the animals from the structures or is access to locations

restricted?

2. The schedule of operations on the site – is the frequency such that they can cause disturbance

to the animals?

The proposed activities must be considered in light of the following attributes and measures for the

Harbour Seal:

- Access to suitable habitat – number of artificial barriers

- Disturbance – frequency and level of impact

- Harbour Seal Sites:

. Breeding sites

. Moulting sites

. Resting sites

Restriction to suitable habitats and levels of disturbance are important pressures that must be

considered to ensure the maintenance of favourable conservation status of the harbour seal and implies

that the seals must be able to move freely within the site and to access locations considered important

to the maintenance of a healthy population. They are categorised according to various life history stages

(important to the maintenance of the population) during the year. Specifically they are breeding,

moulting and resting sites (Figure 3). It is important that the access to these sites is not restricted and

that disturbance, when at these sites, is kept to a minimum. The structures used in culture of oysters

(bags on trestles) can form a physical barrier to seals when both submerged and exposed on the

shoreline such that the access to haul-out locations might be blocked. Activities at sites and during

movement to and from culture sites may also result a disturbance events such that the seals may note

an activity (head turn), move towards the water or actually flush into the water. While such disturbance

events might have been documented, the impact of these disturbances at the population level has not

been studied more broadly (National Research Council, 2009).

Intertidal oyster culture using bags and trestles has been conducted in and around Clew Bay for almost

30 years. The current level of production reflects a gradual increase in activity at the site over this period

and is represented as licenced activities in Figures 5. It is considered that, given the favourable

68

conservation status of Harbour Seals within the SAC represented by stable numbers since 2009 (NPWS

2012) that the current production levels (and activities associated with them) are conducive with

favourable conservation status.

The current activities do not physically overlap with any breeding or moulting locations identified in the

SAC (Figure 17 and 18). It would appear that the current level of activity at the sensitive times of the

year (breeding and moulting, i.e. May to September) is sufficient to maintain stable seal counts at the

site. There appears to be relatively close proximity between some breeding sites and aquaculture

operations (existing and proposed) in the northern portion of the bay. However, it is important to point

out that the activities concerned occur almost exclusively at low water in sand or mud flats with no

residual water that would be conducive to haul out of seals at the sites, i.e. areas proximate to deeper

water in the event of flushing. It is likely that the aquaculture activities occur on the opposite side of the

islands from where the seals haul out and out of direct line of sight. In addition, the level of activity is

unlikely to increase greatly at these sites, as it will be dictated primarily by the tidal duration and extent

of exposed habitat available for exploitation.

As indicated previously, seal interactions with marine finfish cages have been identified (Aquaculture

Stewardship Council, 2012). The risk to seals (as predators) result from their interaction with netting

where if incorrectly configured (loose) the risk of drowning due to being entangled is increased. While

a risk of entanglement in netting may present, it is not considered likely given that slack netting also

presents a risk to culture organism in that it reduces the containment area. In terms of mitigation and in

order to minimise risk to seals, the operators should employ a range of management actions including

stock management (density control, regular removal of mortalities from cages), use of seal blinds and

appropriate net tensioning which are all considered suitable methods to minimise negative interactions

between seals and finfish culture (Aquaculture Stewardship Council 2012). The use of ADDs is not

considered practical. Lethal actions to remove seals are only allowed under licence, the criteria which

are determined by NPWS (Section 42 of the Wildlife Act, 1976 (as amended)).

Conclusion 1: The current levels of licenced aquaculture (existing and renewals) and the new

applications are considered non-disturbing to harbour seal conservation features.

69

Figure 17. Harbour Seal Sites and Aquaculture Sites (licenced and applications) in Clew Bay – North

Figure 18. Harbour Seal Sites and Aquaculture Sites (licenced and applications) in Clew Bay – South

70

8.5 Assessment of the effects of shellfish production on the Conservation Objectives for otter and migrating salmon in Clew Bay Complex SAC.

As the aquaculture production activities within the SAC spatially overlap with Otter (Lutra lutra), and

Salmon (Salmo salar) these activities may have negative effects on the abundance and distribution of

populations of these species.

Otter (Lutra lutra)

Clew Bay Complex SAC is designated for the Otter (Lutra lutra); the conservation objectives for such

are listed in Table 1. The risk of negative interactions between aquaculture operations and aquatic

mammal species is a function of:

1. The location and type of structures used in the culture operations- is there a risk of

entanglement or physical harm to the animals from the structures?

2. The schedule of operations on the site – is the frequency such that they can cause disturbance

to the animals?

Bottom Culture, harvesting and fishing

Given that this culture type does not entail any structures and operations are likely to be carried out in

daylight hours, while the otter foraging is primarily crepuscular, the interaction with bottom culture

operators/operations with the otter is likely to be minimal. It is unlikely that this culture type poses a risk

to otter populations in Clew Bay. Impacts can be discounted.

Oyster and Mussel culture (suspended)

Given the intertidal location of the structures and activities associated this form of oyster culture it is

unlikely that the marine mammals will have any negative interaction with this culture method. Impacts

can be discounted.

The proposed activities will not lead to any modification of the following attributes for otter:

- Extent of terrestrial habitat,

- Extent of marine habitat or

- Extent of freshwater habitat.

- The activity involves net input rather than extraction of fish biomass so that no negative impact

on the essential food base (fish biomass) is expected

- The number of couching sites and holts or, therefore, the distribution, will not be directly

affected by aquaculture and fisheries activities.

- Shellfish production activities are unlikely to pose any risk to otter populations through

entrapment or direct physical injury.

71

- Disturbance associated with vessel and foot traffic could potentially affect the distribution of

otters at the site. However, the level of disturbance is likely to be very low given the likely

encounter rates will be low dictated primarily by tidal state.

Salmon (Salmo salar)

There are two rivers that run into Clew Bay Complex SAC that are designated as SACs for salmon.

These are the Newport River and the Srahmore (Burrishoole). Estimates of the numbers of adult

salmon returning to the Srahmore River represent 50% of the conservation limits based upon 2018

returns (TEGOS 2019). However, these estimates are sufficient to deem the system open for a catch

and release fishery during 2019. In the Newport River, estimates for 1 Sea Winter fish are 165% of

conservation limits. The Newport River continues to met it’s conservation limits (since 2008) and has

had a surplus available for exploitation.

Significant declines in sea survival and reduced returns to the coast and rivers of Atlantic salmon in

recent decades have been recorded in Ireland (Salmon Management Task Force Report (Anon., 1996);

O'Maoileidigh et al., 2004; Jackson et al., 2011). The reasons for the reduced sea survival remain

unclear and speculation has covered such issues as global warming effects (Friedland et al., 2000;

Friedland et al., 2005), changes in locations or availability of prey species, loss of post-smolts as by-

catch in pelagic fisheries, increased fishing pressure, habitat changes and sea lice infestation (Finstad

et al., 2007; SSCWSS 2013). However, despite many years of study, processes contributing to the high

mortality of juvenile Atlantic salmon between ocean entry and the first winter at sea remain poorly

understood (Jones, 2009).

The results of a long term study carried out in the Burrishoole (Jackson et al., 2011) show a strong and

significant trend in increasing marine mortality of Atlantic salmon originating from the Burrishoole

system (i.e. study area). They would also point to infestation of outwardly migrating salmon smolts with

the salmon louse (L. salmonis) as being a minor and irregular component of marine mortality in the

stocks studied and not being implicated in the observed decline in overall survival rate. The results of

this study have been corroborated by studies carried out by the Marine Institute as part of a detailed

investigation into the potential impacts of sea lice on a number of other river systems, including the

Newport River (Jackson et al., 2013).

The Irish State has developed a comprehensive control and management strategy for sea lice

infestations on farmed salmonids. This systems is underpinned by research dating back to the early

1990s and was the basis for the introduction of the original lice monitoring programme (Jackson and

Minchen, 1993). Subsequent research (Jackson et al., 2000; Jackson et al., 2002) informed the

development of a set of management protocols published by the Department of Marine in 2000 (Anon.,

2000). The full implementation of these protocols resulted in improved sea lice control on farmed salmon

(O’Donohoe et al., 2013). There has been a policy of utilising research to ensure that the most up to

date and effective treatment and management regimes are in place to control sea lice on Irish farms

and this has included research into techniques to assess the most effective treatment regimes (Sevatdal

et al., 2005) and the sources of sea lice infestation in the marine environment (Jackson et al., 1997;

Copley et al., 2005; Copley et al., 2007).

72

The monitoring and control system in place is comprehensive, transparent and independent. The Irish

management and control system is widely regarded as best international practice because it has low

treatment trigger levels, is based on independent inspection regimes, has a robust follow-up on problem

areas and Ireland is the only country in the world to publish the results of the independent state run

inspection programme in full each year (O’Donohoe et al., 2013). Following the introduction of the

“Strategy for improved pest control on Irish salmon farms” in 2008 by the Department of Agriculture

Fisheries and Food there were significant improvements in sea lice management in Ireland (Jackson,

2011).

The control strategy is aimed at implementing a more strategic approach to lice control at a bay level

and targeting efforts on the spring period where there is a potential for impacts on wild smolts embarking

on their outward migration. The effectiveness of the system is witnessed by trends in sea lice infestation

on farmed fish in the peak period for wild salmon smolt migration having shown a strong downward

trend since the introduction of the new management strategy (Jackson et al., 2013). As indicated

previously, in relation to disease interactions, any risks of disease transfer between cultured finfish

and wild fish are mitigated by the management systems currently in place. In summary, Council

Directive 2006/88/EC on animal health requirements for aquaculture animals and products thereof, and

on the prevention and control of certain diseases in aquatic animals form the legislative basis that

governs the monitoring and management of disease outbreaks in mariculture operations in Ireland. For

diseases not listed in this Directive, a Code of Practice and Fish Health Handbook has been developed

jointly by the State and industry with the primary objectives of disease prevention and control.

Active veterinary surveillance and intervention has assisted in reducing the prevalence and spread of

many pathogens. In addition, the principles outlined in the Fish Health Handbook mentioned above

such as improved biosecurity practices on farms, fallowing sites to break transmission cycles, veterinary

inspection of fish prior to transfer, single year class stocking, coordinating treatments and harvesting

within embayments etc have mitigated the transmission of pathogenic organisms.

Notwithstanding the issues highlighted above, it is concluded that aquaculture production in

the Clew Bay SAC does not pose any risk to the following salmon attributes:

Distribution (in freshwater)

Fry abundance (freshwater)

Population size of spawners (fish will not be impeded or captured by the proposed

activity)

Smolt abundance (out migrating smolts will not be impeded or captured by the proposed

activity)

Water quality (freshwater)

73

9 Risk Assessment of Fishing Activities

9.1 Risk assessment screening of fisheries

None of the fisheries activities, by definition, can overlap with the following features:

o 1013 Geyer's whorl snail Vertigo geyeri – (terrestrial snail)

o 1210 Annual vegetation of drift lines

o 1220 Perennial vegetation of stony banks

o 1330 Atlantic salt meadows (Glauco‐Puccinellietalia maritimae)

o 2110 Embryonic shifting dunes

o 2120 Shifting dunes along the shoreline with Ammophila arenaria ("white dunes")

o 1150 Coastal Lagoons

Fishery interaction with these features are excluded from further analysis.

9.2 Methodology:

9.2.1 Determining risk to the conservation objectives

The risk assessment framework follows, where feasible, EC guidance (2012) and includes elements of

risk assessment from Fletcher (2004, 2005). The qualitative and semi-quantitative framework is

described in Marine Institute (2013) and criteria for risk categorization is shown in Tables 14 and 15

below.

The framework uses categorical conditional probability matrices of likelihood and consequence to

assess the risk of an activity to a conservation feature. Categorical likelihood and consequence scores

for each such ‘incident’ (fishery-designated feature interactions) are provided by expert judgement and

a base literature resource which has been pre-compiled for each habitat type defined in the COs.

Separate conditional probability matrices for habitats and designated species are used to assess risk.

In the case of habitats the consequence criteria largely follow the definitions and methodologies used

for AA of projects and plans. In the case of species the consequence categories relate to the degree to

which populations and their supporting habitats may be negatively affected by the given activity.

74

Table 14. Risk categorization for fisheries and designated habitat interactions (see: Marine Institute 2013). Colours indicate risk category. Disturbance is defined

as that which leads to a change in characterising species. Such disturbance may be temporary or persistent depending on the frequency of impact and the

sensitivity of the receiving environment. Colours indicate the probable need for mitigation of effects from green (no mitigation needed), to yellow (mitigation

unlikely to be needed but review on a case by case basis), orange (mitigation probably needed) and red (mitigation required)

Habitats Consequence criteria

Activity is not present or has no contact with habitat

Activity occurs and is in contact with habitat

Up to 15% overlap of fishery and habitat seasonally.

Over 15% overlap of fishery and habitat seasonally.

Over 15% of habitat disturbed persistently leading to cumulative impacts

Impact is effectively permanent due to severe habitat alteration.

No change due to fishing activity can occur

Individual effects on characterising species but this is undetectable relative to background natural variability

Seasonal change in characterising species and community structure and function

Seasonal change in characterising species and structure and function

Persistent change in characterising species, structure and function

Biodiversity reduction associated with impact on key structural species

Frequency of disturbance < recovery time. Non-cumulative

Frequency of disturbance> recovery time. Cumulative

No recovery or effectively no recovery

Likelihood % Level 0 1 2 3 4 5

Highly likely >95 5 0 5 10 15 20 25

Probable 50-95 4 0 4 8 12 16 20

Possible 20-50 3 0 3 6 9 12 15

Unlikely 1-20 2 0 2 4 6 8 10

Remote 1 1 0 1 2 3 4 5

75

Table 15. Risk categorization for fisheries and designated species interactions (Marine Institute 2013)

Species Consequence criteria

Activity is not present and individuals or population cannot be affected

Activity present. Individuals in the population affected but effect not detectable against background natural variability

Direct or indirect mortality or sub-lethal effects caused to individuals by the activity but population remains self-sustaining

In site population depleted by the activity but regularly sub-vented by immigration. No significant pressure on the population from activities outside the site

Population depleted by the activity both in the site and outside of the site. No immigration or reduced immigration

Population depleted and supporting habitat significantly depleted and unable to continue to support the population

Likelihood % Level 0 1 2 3 4 5

Highly likely >95 5 0 5 10 15 20 25

Probable 50-95 4 0 4 8 12 16 20

Possible 20-50 3 0 3 6 9 12 15

Unlikely 1-20 2 0 2 4 6 8 10

Remote 1 1 0 1 2 3 4 5

76

9.2.2 Sensitivity of characterizing species and marine communities to physical disturbance by fishing gears

- The approach and rationale to assessment of the sensitivity of species and habitats to fishing

activities and the information used in this assessment is similar to that outlined in 8.2 for aquaculture

- NPWS (2011b) provide lists of species characteristic of the habitats that are defined in the

Conservation Objectives. The sensitivity of these species to various types of pressures varies and

the species list varies across habitats.

- Pressures due to fishing are mainly physical in nature i.e. the physical contact between the fishing

gear and the habitat and fauna in the habitat causes an effect.

- Physical abrasive/disturbing pressures due to fishing activity of each metier maybe classified broadly

as causing disturbance at the seabed surface and/or at the sub-surface.

- Fishing pressures on a given habitat is related to vulnerability (spatial overlap or exposure of the

habitat to the gear), to gear configuration and action, frequency of fishing and the intensity of the

activity. In the case of mobile gears intensity of activity is less relevant than frequency as the first

pass of the gear across a given habitat is expected to have the dominant effect (Hiddink et al.. 2007).

- Sensitivity of a species or habitat to a given pressure is the product of the resilience of the species

to the particular pressure and the recovery capacity (rate at which the species can recover if it has

been affected by the pressure) of the species. Morphology, life history and biological traits are

important determinants of sensitivity of species to pressures from fishing and aquaculture.

- The separate components of sensitivity (resilience, recoverability) are relevant in relation to the

persistence of the pressure

o For persistent pressures, i.e. fishing activities that occur frequently and throughout the year,

recovery capacity may be of little relevance except for species/habitats that may have extremely

rapid (days/weeks) recovery capacity or whose populations can reproduce and recruit in

balance with population reduction caused by fishing. In all but these cases, and if resilience is

moderate or low, then the species may be negatively affected and will exist in a modified state.

Such interactions between fisheries and species/habitats represent persistent disturbance.

They become significantly disturbing if more than 15% of the community is thus exposed

(NPWS 2011b).

o In the case of episodic pressures i.e. fishing activities that are seasonal or discrete in time both

the resilience and recovery components of sensitivity are relevant. If resilience is low but

recovery is high, relative to the frequency of application of the pressure, than the

species/community will be in favourable conservation status for a given proportion of time

- The sensitivities of some species, which are characteristic (as listed in the COs) of benthic

communities, to physical pressures similar to that caused by fishing gears, are described in Table 9.

77

- In cases where the sensitivity of a characterising species (NPWS 2011b) has not been reported this

risk assessment adopts the following guidelines

o Resilience of certain taxonomic groups such as emergent sessile epifauna to physical

pressures due to all fishing gears is expected to be generally low or moderate because of

their form and structure (Roberts et al.. 2010).

o Resilience of benthic infauna (eg bivalves, polychaetes) to surface pressures, caused by pot

fisheries for instance, is expected to be generally high as such fisheries do not cause sub-

surface disturbance

o Resilience of benthic infauna to sub-surface pressures, caused by toothed dredges and to a

lesser extent bottom otter trawls using doors, may be high in the case of species with smaller

body sizes but lower in large bodied species which have fragile shells or structures. Body

size (Bergman and van Santbrink 2000) and fragility are regarded as indicative of resilience

to physical abrasion caused by fishing gears

o Recovery of species depends on biological traits (Tillin et al.. 2006) such as reproductive

capacity, recruitment rates and generation times. Species with high reproductive capacity,

short generation times, high mobility or dispersal capacity may maintain their populations

even when faced with persistent pressures but such environments may become dominated

by these (r-selected) species. Slow recovery is correlated with slow growth rates, low

fecundity, low and/or irregular recruitment, limited dispersal capacity and long generation

times

9.3 Risk assessment of impact of fishing gears on marine benthic communities

The list of fishing activities (métiers) operating in Clew Bay is described in section 4.2 above

The sensitivity of marine communities, which are the subject of the COs to physical disturbance

that may be caused by fishing gears is in Table 9.

The sensitivities of species, characteristic of the marine communities, described in the COs are

in Table 10.

The risk assessment framework outlined in Table 14 and Table 15 for habitats and species

respectively provides a rationale for assessing and scoring risk posed by fishing activities to

the conservation objectives. More detailed explanation is provided in Marine Institute (2013).

One of the risk assessment criteria for habitats is the % overlap of the activity and each habitat.

These % overlaps of fisheries with qualifying interests are presented in Table 16. The overlap

of fisheries and marine community types within those qualifying interests in presented in Table

17.

Risk scores for effects of individual fisheries on marine community types and species are in

Table 18.

78

9.3.1 Potting for shrimp

Shrimp potting occurs throughout inner Clew Bay mainly during the period Sept-Dec

Shrimp potting overlaps with 38% of Habitat 1160 and with marine community types in Habitat

1160 as follows; 87% of Zostera community, 34% of Maerl community, 33% with sandy mud

with polychaetes and bivalves, 36% with fine sand with N. cirrosa and 86% of sub-tidal faunal

and Laminaria reef.

The actual footprint of static gear such as shrimp pots is expected to be much lower than the

percentage of the area over which the fishery might occur

The risk posed by shrimp potting and associated surface disturbance in sub-littoral sandy muds

and in fine sand is low as the associated species are infaunal and are largely protected from

surface disturbance. These species are not sensitive to surface disturbance (ABPMer 2013e,

Evidence Proformas Appendix F)

Maerl is highly sensitive to surface disturbance or physical impacts. Maerl thalli can be crushed

and the surface matrix can be altered. Maintenance of structural integrity of the maerl thalli is

important in maintaining biodiversity of associated species (ABPMer 2013b, Evidence

Proformas, Appendix F)

Zostera has moderate to high sensitivity to surface disturbance and high sensitivity to intensive

potting activity (Hall et al 2008, ABPMer 2013a, Evidence Proformas, Appendix F)

Faunal reef and Laminaria reef habitats have low sensitivity to static fishing gears although the

sensitivity of species in these habitats may vary depending on life history characteristics

(ABPMer 2013h, Evidence Proformas Appendix F). Damage from pots could be caused by

direct impact of pots on the seabed, the effects of ropes on emergent epifauna or seaweeds

and from anchors which may drag during hauling of gear. Cumulative damage to sensitive

species could result if the intensity of the activity is high. Emergent sessile epifauna such as

Alcyonium, Cliona and Echinus may be impacted by pots, ropes and anchors. However, these

species have medium resilience and high recoverability to physical abrasion. Laminaria and

macroalgae in this habitat have low sensitivity to single abrasive events.

Potting for shrimp may cause non-cumulative disturbance of faunal reef and Laminaria

reef.

9.3.2 Potting for prawns

Potting for prawns occurs on mud and sandy mud substrates in the middle of Clew Bay mainly

outside of the SAC.

Prawn potting overlaps with 10% of Habitat 1160 and with marine community types in Habitat

1160 as follows; 6% with sandy mud with polychaetes and bivalves and 36% of sub-tidal faunal

and Laminaria reef. Overlap with reef is an artifact of the poor resolution of the fishing data

relative to the scale of the marine community features as Nephrops does not occur in reef

habitat.

This habitat and associated species are not sensitive to surface disturbance (ABPMer 2013e,

Evidence Proformas Appendix F)

79

The risk posed by prawn potting to sandy mud communities is deemed to be low and

insignificant.

9.3.3 Potting for crab and lobster

Crab and lobster potting occurs throughout inner Clew Bay. Activity is higher during summer

months

Crab and lobster potting overlaps with 17% of Habitat 1160 and with marine community types

in Habitat 1160 as follows; 12% with sandy mud with polychaetes and bivalves and 55% of sub-

tidal faunal and Laminaria reef.

The actual footprint of static gear such as shrimp pots is expected to be much lower than the

percentage of the area over which the fishery might occur

The risk posed by crab and lobster potting to sandy mud communities is deemed to be low and

insignificant. This habitat and associated species are not sensitive to surface disturbance

(ABPMer 2013e, Evidence Proformas Appendix F)

Faunal reef and Laminaria reef habitats have low sensitivity to static fishing gears although the

sensitivity of species in these habitats may vary depending on life history characteristics

(ABPMer 2013h, Evidence Proformas Appendix F). Damage from pots could be caused by

direct impact of pots on the seabed, the effects of ropes on emergent epifauna or seaweeds

and from anchors which may drag during hauling of gear. Cumulative damage to sensitive

species could result if the intensity of the activity is high. Emergent sessile epifauna such as

Alcyonium, Cliona and Echinus may be impacted by pots, ropes and anchors. However, these

species have medium resilience and high recoverability to physical abrasion. Laminaria and

macroalgae in this habitat have low sensitivity to single abrasive events.

Potting for lobster and crab may cause non-cumulative disturbance of faunal reef and

Laminaria reef. The likelihood of disturbance is higher than for shrimp potting as the

activity is more likely to target reef areas and the gear units are heavier and may cause

more abrasion than shrimp pots.

9.3.4 Potting for whelk

Potting for whelk began in 2013 in the north east of the Bay on sandy mud community.

The spatial overlap is unknown. Given that the stock has probably been depleted the

fishery is unlikely to continue to any significant degree.

The risk posed by whelk potting to sandy mud communities is deemed to be low and

insignificant. This habitat and associated species are not sensitive to surface disturbance

(ABPMer 2013e, Evidence Proformas Appendix F).

9.3.5 Tangle netting for crayfish

Tangle netting for crayfish occurs throughout the Clew Bay area. Most of the activity is outside

of the SAC

80

Spatial overlap with designated habitats and marine community types is not calculated as

tangle nets have minimal contact with the seabed

There is no overlap with sensitive reef habitat such as Zostera and Maerl.

There is some overlap with Laminaria dominated and faunal reef habitat

Ropes and anchors from bottom set nets may cause surface and sub-surface abrasion in reef

habitat. The footprint of this pressure however is likely to be very small and in reality the fishery

is highly unlikely to occur in the Laminaria zone and more likely to occur in faunal reef.

The reef habitat has low sensitivity to physical abrasion although species sensitivity may vary

from low to high. Emergent sessile epifauna such as Alcyonium, Cliona and Echinus may be

impacted by ropes and anchors. However, these species have medium resilience and high

recoverability to physical abrasion

The risk posed by the tangle netting activity to reef habitats is low

9.3.6 Gill netting for Pollack and mackerel

Gill netting for Pollack and Mackerel occurs throughout the Clew Bay area. Most of the activity

is outside of the SAC

Spatial overlap with designated habitats and marine community types is not calculated as

tangle nets have minimal contact with the seabed

There is no overlap with sensitive reef habitat such as Zostera and Maerl.

There is some overlap with Laminaria dominated and faunal reef habitat in the SAC








The risk posed by the gill netting activity to reef habitats is low

9.3.7 Dredging for scallop

Dredging for scallop occurs on sedimentary and reef habitat in Clew Bay mainly outside of the

SAC.

Based on expert data scallop dredging overlaps with 47% of Habitat 1160. Scallop dredging

overlaps with marine community types in Habitat 1160 as follows; 54% with Zostera, 63% with

Maerl, 42% with sandy mud with polychaetes and bivalves, 56% with fine sand with N. cirrosa

and 90% of sub-tidal faunal and Laminaria reef.

Maerl is highly sensitive to physical surface and sub-surface abrasion pressure caused by

mobile fishing gears such as scallop dredging. There is a high risk that maerl will be killed and

that habitat structure and associated biodiversity will be eroded (ABPMer 2013b, Evidence

Proformas Appendix F)

81

Zostera has no or low resistance to shallow disturbance caused by dredging. Resistance is

slightly higher in harder sediments compared to soft sediments. Recovery is medium to low

(>6yrs) depending on the extent of the impact. When large areas are impacted recovery will be

longer. There is a high risk that Zostera will be uprooted and killed by scallop dredges (ABPMer

2013a, Evidence Proformas Appendix F).

Faunal reef habitat is not sensitive to surface abrasion but associated species may have low or

high sensitivity to this pressure and to sub-surface disturbance caused by scallop dredging.

Emergent epifauna are sensitive to physical disturbance. Species such as Echinus and

Metridium have low resistance but moderate resilience to physical abrasion. As some species

associated with faunal reef habitat have high sensitivity to physical abrasion there is a risk that

the species composition of these reefs may be altered by scallop dredging (ABPMer 2013h,

Evidence Proformas Appendix F).

Laminaria reef is generally resistant to surface abrasion and recovery is also high. However,

resistance is low to repeated abrasive pressure combined with entanglement, removal of

holdfasts and possible habitat disturbance (capture of stones and boulders in gear). The impact

will depend on frequency and intensity of the activity (ABPMer 2013, Evidence Proformas

Appendix F).

Scallop dredging poses significant risk to Zostera, Maerl and reef habitats and less so

to sedimentary habitats.

9.3.8 Dredging for oyster

Dredging for oyster occurs on sedimentary and reef habitat in Clew Bay.

Based on MI survey data oyster dredging overlaps with 0.9% of Habitat 1160 and 0.04% of

Habitat 1140. Oyster dredging overlaps with marine community types in Habitat 1160 as

follows; 1% with Zostera, 1% with Maerl, 1% with sandy mud with polychaetes and bivalves

and 1% of Laminaria reef. Overlaps with QI 1140 are 1% on Intertidal sandy mud and 1% on

sandy mud.

The survey data may not cover the entire area over which oyster are distributed and may not

reflect the current distribution of commercial densities of oyster and therefore may or may not

be representative of the distribution of fishing activity. However, oyster stocks are depleted and

the fishery is unlikely to extend over significant areas of habitat over and above the % quoted

above

Maerl is highly sensitive to physical surface and sub-surface abrasion pressure caused by

mobile fishing gears such as oyster dredging. There is a high risk that maerl will be killed and

that habitat structure and associated biodiversity will be eroded (ABPMer 2013b, Evidence

Proformas Appendix F)

Zostera has no or low resistance to shallow disturbance caused by dredging. Resistance is

slightly higher in harder sediments compared to soft sediments. Recovery is medium to low

depending on the extent of the impact. When large areas are impacted recovery will be longer.

82

There is a high risk that Zostera will be uprooted and killed by oyster dredges (ABPMer 2013a,

Evidence Proformas Appendix F).

Dredging in sedimentary habitats has the potential to change sediment composition and lead

to associated changes in faunal communities. However, these habitats and associated species

have no or low sensitivity to surface and shallow disturbance caused by oyster dredging

(ABPMer 2013e, Sensitivity Matrices_Appendix E)

Oyster dredging poses significant risk to Zostera and Maerl habitats and less so to

sedimentary habitats. However, spatial overlaps between the fishery and Zostera and

Maerl habitats are very low and the likelihood of a cumulative effect is therefore low. The

spatial distribution of the fishery however depends on the status of oyster stocks. The

footprint of the fishery could expand if oyster stocks recovered.

9.3.9 Bottom trawling for mixed demersal fish

No bottom trawling for mixed demersal fish occurs in the SAC.

Risks to habitats from this activity can be discounted

9.3.10 Midwater trawling for pelagic fish

No mid water trawling for pelagic fish occurs in the SAC.

Risks to habitats can be discounted.

9.3.11 Hook and line fishing for mackerel

Trolling for mackerel and Pollack may occur in the outer area of the SAC

Trolling poses no risk to habitats or constituent marine communities

9.3.12 Draft net fishing for salmon

Draft net fishing for salmon may occur in estuaries of rivers flowing into Clew Bay

Draft netting poses no risk to habitats or constituent marine communities

9.3.13 Trammel net fishing for bait

Trammel netting for bait may occur throughout the Bay but is more likely to occur in reef areas

There is some overlap with Laminaria dominated and faunal reef habitat








The risk posed by the trammel netting activity to reef habitats is low

83

9.3.14 Hand gathering of periwinkle and cockle

The distribution of hand gathering for periwinkle is unknown but by definition it is restricted to

intertidal habitat

It is likely to occur on shores dominated by Ascophyllum and Fucus seaweeds

High trampling pressure from hand gatherers on Fucus and Ascophyllum communities can

cause community change.

Resistance of these species is Low-Moderate while resilience is Moderate to very High. The

sensitivity of species to trampling is low (ABPMer, 2013h, Evidence Proforma Appendix F).

Seasonal change in the abundance of characterizing species may occur due to trampling but

this is very unlikely to be cumulative.

Hand gathering of cockles could result in trampling and physical disturbance of fauna, mortality

of fauna and extraction of cockles. Its effect is likely to be non cumulative although unrestricted

intensity and frequency of such activity could lead to cumulative effects on intertidal

sedimentary communities. The fishery is not currently active.

The risk posed by hand gathering to intertidal reef communities is likely to be low but

could be significant locally depending on the frequency and intensity of the activity.

9.3.15 Cumulative effects of fishing on marine communities

Fishing pressures from all metiers combined declines eastwards, from the centre to the eastern

shores of the Bay (Figures 20-23).

Up to 9 metiers may be active towards the western edge of the SAC and this number of

overlapping metier declines eastwards.

These métiers are potting for crab, lobster, shrimp and prawns, dredging for scallop, dredging

for oyster, tangle/gill netting, trammel netting and trolling.

Multiple overlapping fishing métiers occur in Laminaria and faunal reef habitat and in sandy

mud sedimentary habitat.

The cumulative risk posed by static gears (potting, tangle/gill netting, trammel netting) to sandy

mud sedimentary habitats is low as these gears do not individually have a significant impact on

sedimentary habitats.

Potting metiers may individually cause non-cumulative disturbance in faunal and Laminaria

reefs. The cumulative risk posed by static gears (potting, tangle/gill netting, trammel netting) to

reef habitats is similar to the individual scores; these gears are used only seasonally (especially

netting), the quantity of netting in the SAC is low and netting is unlikely to occur in Laminaria

reef. Cumulative effects (and higher consequence) are unlikely.

The cumulative risk posed by mobile dredging gears in sedimentary or reef habitats is low

because oyster fishing is limited in extent and adds little extra cumulative pressure over and

above scallop fishing

Although potting metiers may cause non-cumulative disturbance in faunal and Laminaria reefs

these effects are likely to be benign relative to the effects of scallop dredging in reef. As such

84

cumulative effects of potting and dredging are small relative to the single effect of scallop

dredging.

Cumulative fishing pressure on Zostera and Maerl arises from Shrimp potting, Scallop dredging

and Oyster dredging. The additive effect of oyster dredging is insignificant as less than 1% of

Zostera and Maerl have overlaps with oyster fishing. As with Reef habitat the cumulative effect

of shrimp potting and scallop dredging on Zostera and Maerl are small relative to the single

effect of scallop dredging.

Figure 19. The distribution of fishing activity (count = number of fishing metier) in relation to

Laminaria reef communities in Clew Bay SAC.

85


faunal reef communities in Clew Bay SAC


Zostera communities in Clew Bay SAC

86


Maerl communities in Clew Bay SAC

87

Table 16. Percentage (%) overlap of fisheries with seabed habitats and qualifying interests 1140 and 1160.

Metier Target species 1140_Mud and

sand flats

1160 - Large shallow inlets and

bays

% of Feature % of Feature

Potting_Shrimp Palaemon serratus 0 38

Potting_lobster/crab Homarus gammarus, Cancer pagurus, Maja brachydactyla 0 17

Potting_prawns Nephrops norvegicus 0 10

Dredging_scallops Pecten maximus 0 46.7

Dredging_oysters Ostrea edulis 0 1

Tangle netting_crayfish Palinurus elephas 0 <1

Gill netting_pollack/mackerel Pollachius pollachius, Scomber scomber 0 <1

Netting_bait Mixed fish 0 17

Bottom trawling_demersal fish Mixed fish species 0 0

Mid-water trawling_pelagic fish Clupea harengus, Sprattus sprattus 0 0

Lining_pollack/mackerel Pollachius pollachius, Scomber scomber 0 0

Draft netting_salmon Salmo salar 0 <1

Hand gathering Littorina littorea, Cerastoderma edule Unknown Unknown

88

Table 17. Percentage overlap of fishing metiers, which have significant contact with the seabed, with marine community types in Habitats 1140 and

1160 in Clew Bay. MCTs with shading have no fishery overlapping with them

Qualifying interest code Qualifying interest name Marine Community Type (MCT)

Tra

p -

lo

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ter

Tra

p -

cra

b

Tra

p -

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rim

p

Tra

p -

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ps

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Tra

p -

Wh

elk

Dre

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r

Dre

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Gil

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Ta

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cra

yfi

sh

Tra

mm

el n

ett

ing

ba

it

Ott

er

traw

l -

de

me

rsa

l

Mid

-wa

ter

traw

l

Han

d g

ath

eri

ng

win

kle

s

Han

d g

ath

eri

ng

co

ck

les

Ho

ok

s a

nd

Lin

es

1140

Mudflats and sandflats not covered by seawater at low tide [1140]

Intertidal sandy mud with Tubificoides benedii and Pygospio elegans community complex 0 0 0 0 0 0 1 4 0 0 0 0 0 0 4 0

1140


Sandy mud with polychaetes and bivalves community complex 0 0 0 0 0 0 1 2 0 0 0 0 0 0 2 0

1140


Fine sand dominated by Nephthys 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1160 Large shallow inlets and bays [1160] Zostera dominated community 0 0 87 0 54 0 1 0 0 0 0 0 0 0 0 0

1160 Large shallow inlets and bays [1160] Maërl-dominated community 0 0 34 0 63 0 1 0 0 0 0 0 0 0 0 0

1160 Large shallow inlets and bays [1160]

Sandy mud with polychaetes and bivalves community complex 12 12 33 6 42 ? 1 0 0 0 12 0 0 0 0 0


Fine sand dominated by Nephtys cirrosa community complex 0 0 36 0 56 ? 0 0 0 0 0 0 0 0 0 0

1160 Large shallow inlets and bays [1160] Shingle 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0


Reef (intertidal, faunal and Laminaria) 55 55 86 36 90 90 0 0 0 0 55 0 0 ? 0 0

89

Table 18. The categorical risk (= consequence*likelihood of consequence) posed by bottom contacting gears each fishing activity to marine

communities. Blank cells indicate no spatial overlap or occurrence of the fishery in the MCT. Colour codes indicate the probable need for mitigation

as described in Tables 15 and 16 (See section 9.2.1).

Qualifying interest name and code Marine Community Type (MCT)

Tra

p -

lo

bs

ter

Tra

p -

cra

b

Tra

p -

sh

rim

p

Tra

p -

Nep

hro

ps

Tra

p -

Wh

elk

Dre

dg

e -

sca

llo

p

Dre

dg

e o

yste

r

Dre

dg

e c

ock

le

Gil

l n

et

Ta

ng

le n

et

cra

yfi

sh

Tra

mm

e n

ett

ing

ba

it

Ott

er

traw

l -

de

me

rsa

l

Mid

-wa

ter

traw

l

Han

d g

ath

eri

ng

win

kle

s

Han

d g

ath

eri

ng

co

ck

les



=2*3 =4*4 =4*3



=2*3 =4*4 =4*3

Large shallow inlets and bays [1160] Zostera dominated community =4*3

=4*4 =4*4

Large shallow inlets and bays [1160] Maërl-dominated community =4*4

=5*4 =5*4

Large shallow inlets and bays [1160]

Sandy mud with polychaetes and bivalves community complex =1*4 =1*4 =1*3 =1*3 =1*3 =4*3 =2*3 =1*4


Fine sand dominated by Nephtys cirrosa community complex =1*3 =1*3 =4*3


Reef (intertidal, faunal and Laminaria) =3*3 =3*3 =3*3 =1*4

=4*4 =2*4 =3*3 =4*3

90

9.4 Risk assessment of impact of fishing gears on designated species harbour seal, otter and salmon

9.4.1 Conservation objectives, status and habitat use

9.4.1.1 Harbour Seal

Harbour seals are listed in Annex II of the Habitats Directive. Although the species is wide ranging in

the marine environment the Directive requires Members States to establish Special Areas of

Conservation to protect them. Harbour seal use specific sites for breeding, moulting and resting and

have some degree of fidelity to these areas while also undertaking migrations and foraging movements

in open water outside of the sites for which they are designated.

The conservation objectives for Harbour seal have explicit targets

1. The species range within the site should not be restricted by artificial barriers

2. Breeding sites should be conserved in natural condition

3. Moult haul-out sites should be conserved in natural condition

4. Resting haul-out sites should be conserved in natural condition

5. Human activities should occur at levels that do not adversely affect the Harbour seal population

at the site

Harbour seals are common in Clew Bay SAC and use a variety of locations for haul out, breeding and

moulting. Their population in Clew Bay has increased; the 2003 census recorded 95 seals compared

to 241 in 2011. Although the behavior and foraging range of Harbour seals and their use of marine

habitats in Clew Bay is not well known it is expected, and as described in the conservation objectives,

that all areas of the Bay are used as foraging habitat and that their foraging range would extend well

beyond the boundaries of the SAC into open water to the west towards Clare Island. Harbour seals may

forage up to 30km from haul out sites in search of prey (Cordes et al 2011).

9.4.1.2 Otter

Otter (Lutra lutra) is listed in Annex II of the Habitats Directive. Otter is common throughout freshwater

systems in Ireland and also occurs in coastal marine habitats.

The conservation objectives for Otter in the marine environment have explicit targets

1. No significant decline in distribution

2. No significant decline in marine habitat

3. No significant decline in couching sites and holts

4. No significant decline in available fish biomass

5. No significant increase in barriers to connectivity

Otter population in Clew Bay may be depleted relative to the favourable conservation status which is

based on 1980/81 survey findings of 88% positive survey sites (NPWS 2011). Otters use marine habitat

in Clew Bay to an extent; otters may swim in open water to cross between islands or islands and the

91

mainland and may forage in shallow water 80m from the shore (NPWS 2011). Prey includes rockling

and wrasse in shallow reef areas.

9.4.1.3 Salmon

The conservation objectives for Salmon have explicit targets related mainly to populations and habitat

requirements in freshwater. The following targets could be affected by marine fisheries (including

salmon fisheries)

1. The conservation limit for the number of spawning fish should be consistently exceeded. This

is the spawning level that produces long term average maximum sustainable yield as derived

from the adult to adult stock and recruitment relationship

2. There are also density or population targets for fry and outward migrating smolt abundance

The Newport River flowing into the north east corner of Clew Bay is designated for salmon (Salmo

salar). Salmon smolts migrate from the Newport into marine waters of Clew Bay during April-May and

return as one sea winter fish or two sea winter fish during the following year(s). The Newport River

salmon stock is small with a conservation limit (which is the number of fish or stock level that maximizes

the long term average harvestable surplus) of 7,811 sea winter fish. Currently the stock is above this

level for 1 sea winter fish but below the conservation limit for 2 sea winter fish. Unplanned capture of

salmon i.e. by catch of salmon in fisheries other than the draft net fisheries could compromise the stocks

capacity to reach its conservation limit.

9.4.2 Risk of capture


There is no risk of capture of Harbour seal in shrimp pots, crab lobster pots, prawn pots, oyster

dredges, scallop dredges, salmon draft nets or in hook and line fisheries.

There is a low risk of capture of Harbour seals in mid-water trawls operating to the west of the

SAC. Grey seals are captured in mid-water trawls (Morizur et al.. 1999).

The highest risk of capture of Harbour seal is in tangle nets, gill nets and trammel nets.

Cosgrove et al. (2013) reported capture of 10 Harbour seals overall in 320mm mesh tangle

nets (8 seals) and 270mm trammel nets (2 seals) over 91 days observed at sea, 358 hauls and

1071km of mixed tangle net, gill net and trammel net gear.

There is significant geographic variability in by-catch. In Clew Bay the set net fisheries are

remote from the haul out sites given the foraging range of 30km. However, Cosgrove et al

(2013) report the capture of Harbour Seal in large mesh (320mm) tangle nets south of Achill.

These seals may have belonged to the Clew Bay population.

Reliable estimates of by-catch cannot be estimated from the profile and quantity of set net gears

being used in the Bay and west of the Bay.

Cumulative risk posed by fisheries may result in sub-lethal and lethal effects on individual

harbour seals but the population (as shown by census data) is showing significant increases

and is self-sustaining.

92

9.4.2.2 Otter

There is no risk of capture of otter in shrimp pots, prawn pots, oyster dredges, scallop dredges,

salmon draft nets, in hook and line fisheries or in bottom trawl or mid water trawl fisheries

occurring to the west of the SAC. .

Otters can be trapped in lobster/crab creels. This risk depends on the creel design and in

particular its size, the design of the eye entrance and whether parlours or double chambers are

used inside the pot. Female otters are more susceptible because of their smaller size (Twelves

1983). The risk of otter capture in creels in Clew Bay can be regarded as low because

lobster/crab creeling occurs in deeper water inaccessible to otters.

Trammel nets are used by lobster/crab fishermen to catch fish for bait. Bait species targeted by

trammel nets include wrasse and rockling which are preyed upon by otter. As the foraging

habitat and areas where trammels might be used overlap there is some risk of capture of otter

in trammel nets

Tangle nets and bottom set gill nets are used in open deeper water and as such are unlikely to

pose a risk to otter.

9.4.2.3 Salmon

There is no risk of capture of salmon smolts or adult salmon in shrimp pots, lobster/crab pots,

prawn pots, troll lines, oyster dredges or scallop dredges

There is a very minor risk of capture of salmon in tangle and gill nets. As these are bottom set

nets they are unlikely to overlap with salmon which swim in surface waters. There is no risk of

capture of salmon smolts in tangle nets or gill nets as the mesh is large.

The risk of capture of salmon in bottom trawls west of the SAC is minor as this activity occurs

on the seabed. The risk of capture in mid-water trawls may be higher. However, sampling of

demersal and pelagic fisheries in Irish waters have not recorded any salmon by-catch. In

addition there is very little pelagic fishing in quarter 2 and 3 (Apr-Sept) during the smolt

migration and during the return of 1SW fish to the coast

Salmon smolts and adult salmon could be captured in trammel nets if these nets are set in

shallow water along reef. These nets are more commonly used in spring and summer

Salmon are targeted by salmon draft nets. However, these are licenced only when there is a

harvestable surplus available and the number of fish that can be captured is defined by a total

allowable catch. The number of licences in the Newport estuary is 1 so there is no risk of TAC

overshoot. The draft net fishery, therefore, poses no risk to the sustained productivity of salmon

populations.

93

9.4.3 Risk of prey depletion

9.4.3.1 Harbour seal

Harbour Seal feed on Herring, Sprat, Sandeel and gadoids (Wilson et al. 2002) and are

opportunistic feeders able to switch prey according to availability. Herring and Sprat are more

nutritionally valuable to Harbour Seals than Gadoids.

There is no demersal or pelagic fishing activity within the SAC and levels of activity by these

fisheries in Clew Bay generally is low suggesting that there is little potential for Harbour Seal

prey depletion due to these fisheries

Gill netting and hook and line fishing for Pollack and mackerel removes potential prey for

Harbour seal. However these are small scale fisheries and the volume of fish removed is low

Other fisheries in Clew Bay target crustaceans and bivalves which are not important prey items

9.4.4 Otter

Otter may feed on wrasse and rockling and invertebrates in shallow marine waters of Clew Bay

Although trammel netting removes potential prey species of otter the level of trammel netting

activity is highly unlikely to deplete these fish and invertebrate resources significantly

9.4.4.1 Salmon

Salmon smolts migrating to sea do not spend any significant amount of time in Clew Bay. They

migrate directionally into oceanic waters within a few days of migrating to sea

Returning adult salmon migrate directionally into freshwater on entering Clew Bay and are not

dependent on fish prey in the Bay

9.4.5 Risk of disturbance


Hand gathering activity if close to seal haul out sites may cause disturbance.

Fishing vessel activities may cause disturbance events but are unlikely to represent a

disturbance effect that would lead to abandonment of the haul out site or render the haul out

site unsuitable. Dredging for oyster and scallop occurs close to some islands in inner Clew Bay

that may be used for haulout sites.

9.4.5.2 Otter

None of the fisheries in Clew Bay are likely to be disturbing to otter. Fishing is highly unlikely to

impede or disturb movements of otter or habitat use by otter in the Bay.

9.4.5.3 Salmon

None of the fisheries in Clew Bay represent a disturbance that is likely to impede normal routes

of migration into and out of Clew Bay. The draft net fishery intercepts a limited number of salmon

only when there is a harvestable surplus.

94

9.4.6 Cumulative effects of fishing on designated species

Tangle netting, gill netting, trammel netting and to a lesser extend mid-water trawling and otter

trawling combine to increase the risk of by-catch of Harbour Seal (Table 19)

The cumulative risk does not appear to contrary to the achievement of conservation objectives

for Harbour Seal in inner Clew Bay as the population is increasing.

95

Table 19. Risk (consequence*likelihood of consequence) of by-catch, prey depletion and

disturbance by fisheries to designated species in Clew Bay

Risk

Metier Pressure Harbour Seal Otter Salmon

Tangle net

By-catch =2*3 =1*1 =1*1

Prey depletion =1*1 =1*1 =1*1

Disturbance =1*1 =1*1 =1*1

Gill net

By-catch =2*3 =1*1 =1*1



Trammel net

By-catch =2*3 =1*1 =1*1



Pelagic trawl

By-catch =1*3 =1*1 =1*1



Demersal trawl

By-catch =1*3 =1*1 =1*1



Pots

By-catch =1*3 =2*2 =1*1



Dredges

By-catch =1*1 =1*1 =1*1



9.5 Fisheries risk profile

9.5.1 Marine Community types

Based on the fishing descriptions and the marine community types defined in the conservation

objectives of 135 possible marine community type – fishery interactions in Clew Bay, 31 were

found to be present (Table 18).

Non cumulative seasonal disturbance was assessed as possible or probable in the following

interactions

o Potting for shrimp on Zostera

o Potting for shrimp on faunal or Laminaria reef

o Potting for crab/lobster on faunal or Laminaria reef

o Dredging for scallop on sandy mud with polychaetes and bivalves community complex

96

o Dredging for scallop in fine sand dominated N. cirrosa community

o Dredging for oyster on sandy mud with polychaetes and bivalves community complex

o Hand gathering on reefs

Cumulative impacts are possible, probable or highly likely in 6 cases. However, the spatial

overlaps of current fishing activity and some of these communities are very low (1%) as

indicated in Table 18.

o Scallop dredging in Zostera (cumulative impacts highly likely)

o Scallop dredging in faunal or Laminaria reef (cumulative impacts probable)

o Potting for shrimp in Maerl communities (cumulative impacts possible)

o Dredging for oyster on Zostera (very low overlap)

o Dredging for oyster on Maerl (very low overlap)

o Dredging for oyster on faunal or Laminaria reef (very low overlap)

Non-cumulative seasonal disturbance effects will depend on the intensity and frequency

of the activity. Specific studies or additional data would usefully inform the degree to

which such effects are likely to occur and whether they could ever result in cumulative

effects

Cumulative effects need to be managed to reduce the risk to the conservation objectives.

However, there are different likelihoods of such cumulative effects occurring and each

fishery-habitat interaction should be considered case by case in considering

mitigations.

9.5.2 Species

Considering the 3 pressures (by-catch, prey depletion, disturbance) posed by fishing activity on Harbour

seal, otter and salmon although population level effects are unlikely in any species sub-lethal or lethal

effects on individuals in the population is possible or probable in the following cases (Table 19).

o By-catch of Harbour Seal in large mesh tangle nets in the site or to the west of the site.

Other nets may also pose a risk (possible)

o By-catch of Otter in lobster creels in the site (unlikely)

o Depletion of prey resources available to Harbour Seal resulting from pelagic fishing

(possible)

10 In-combination effects of aquaculture, fisheries and other activities

The spatial distribution of aquaculture and fisheries activities are non-overlapping. Aquaculture in

mainly in the intertidal habitat while fishing activity is mainly in subtidal areas and is higher at the western

edges of the SAC. There are no significant in-combination effects on habitats given that each sector

works in largely different habitats.

97

Intertidal aquaculture activity may pose some disturbance potential to Harbour Seal. Certain fishing

activities such as hand gathering in the intertidal area and fishing in shallow waters seaward of haul out

sites may produce a cumulative disturbance effect on harbour seal. Nevertheless as harbour seal

conservation objectives are being met the existing cumulative activities do not appear to pose a

significant risk to Harbour Seal.

Other activities leading to potential impacts on conservation features relate to harvest of seaweed on

intertidal reef communities. There is little known concerning the level of harvest from these intertidal

reef communities. The impact is likely two-fold, direct impact upon the reefs by removal of a constituent

species and impact upon intertidal sediments as a consequence of travel across the shore to the harvest

sites. The likely overlap between these activities and intertidal shellfish culture is considered small as

the (reef) habitat is not considered suitable for shellfish culture. Seaweed harvesting requires a

foreshore licence administered by the Department of Environment, Community and Local Government.

The level of transport across the intertidal area is unknown, but it is presumed that the routes are well

defined. Similarly, it is expected that well defined routes are also used to access islands where farm

animals and dwellings are located. It is unlikely that the in-combination impacts of transport routes

across the intertidal flats will result in a persistent disturbance of >15% on intertidal sandflats and

mudflats.

There are a number of activities which are terrestrial in origin that might result in impacts on the

conservation features of the Clew Bay Complex SAC. Primary among these are point source discharges

from municipal and industrial units (Shellfish Pollution Reduction Programme, DECLG). There are five

urban waste water treatment plants in the general vicinity of the SAC. These are found in Louisburgh,

Mulranny, Newport, Old head and Westport. There are also water treatment plants at Louisburgh,

Newport and Westport. The pressure derived from these facilities is a discharge that may impact upon

levels of dissolved nutrients, suspended solids and some elemental components e.g. aluminium in the

case of water treatment facilities. The only in-combination effect of these activities with aquaculture and

fisheries activities relates to discharge (excreta) from salmon net pens which is nitrogenous (NH4+) in

nature. For dissolved compounds, given the residence time of Inner Clew Bay has been estimated at

between 1.3 and 13 days (Tomasz Dabrowski, Marine Institute – pers comm.), the likelihood of a

persistent disturbance on the SAC is considered low and in-combination effects are considered unlikely.

Particulate matter originating from fish cages will typically be confined to a small area broadly

corresponding to the cage footprint. Suspended matter will likely fall out of solution very close to the

discharge point and will unlikely aggravate the impact beneath fishfarm cages and vice-versa. It should

be noted that the pressures resulting from fisheries and aquaculture activities are primarily

morphological in nature. It was, therefore, concluded that given the pressure resulting from say, a point

discharge location (e.g. urban waste-water treatment plant or combined sewer overflow) would likely

impact on physico-chemical parameters in the water column, any in-combination effects with

aquaculture or fisheries activities was considered to be minimal or negligible notwithstanding the

interaction with finfish culture identified above. Furthermore, recent water quality results from Clew Bay

as part of Water Framework Directive monitoring has reported that Clew Bay waterbodies have

achieved high ecological quality status (R. Wilkes – EPA - personal communication).

98

11 SAC Aquaculture Appropriate Assessment Concluding Statement and Recommendations

In Clew Bay Complex SAC there are a range of aquaculture activities currently being carried out or

proposed. Based upon this and the information provided in the aquaculture profiling (Section 5), the

likely interaction between this culture methodology and conservation features (habitats and species) of

the site were considered.

11.1 Habitats

An initial screening exercise resulted in a number of habitat features being excluded from further

consideration by virtue of the fact that no spatial overlap of the culture activities was expected to occur.

The habitats and species excluded from further consideration were 1013 Geyer's whorl snail Vertigo

geyeri, 1210 Annual vegetation of drift lines, 1220 Perennial vegetation of stony banks, 1330 Atlantic

salt meadows (Glauco-Puccinellietalia maritimae), 2110 Embryonic shifting dunes, 2120 Shifting dunes

along the shoreline with Ammophila arenaria ("white dunes"), 1150 Coastal Lagoons.

A full assessment was carried out on the likely interactions between aquaculture operations (as

proposed) and the feature of the Annex 1 habitats 1140 (Mudflats and sandflats not covered by

seawater at low tide) and 1160 (Large Shallow Inlets and Bay) as well as the species; harbour seal,

salmon and otter. The likely effects of the aquaculture activities (Species, structures, transport routes)

were considered in light of the sensitivity of the constituent habitats and species of the Annex 1 habitats.

Conclusion and Recommendation: Based upon the scale of spatial overlap and the relatively high

tolerance levels of the community types and species therein and given the likely interactions between

current and proposed aquaculture activities with these habitats, it is concluded that consideration can

be given to licencing (existing and applications) in the Annex 1 habitats – 1140 (Mudflats and sandflats

not covered by seawater at low tide) and 1160 (Large Shallow Inlets and Bays).

The movement of stock in and out of Clew Bay Complex SAC should adhere to relevant fish health

legislation and follow best practice guidelines.

Methods should be employed to ensure that structures and netting are kept clean at all times and that

any biofouling by alien invasive species be removed and disposed of in a responsible manner, such

that it will not pose a risk to the conservation features of the site.

99

11.2 Species

The likely interactions between the proposed aquaculture activities and the Annex II Species Harbour

Seal (Phoca vitulina) and Otter (Lutra lutra) were also assessed. The objectives for these species in the

SAC focus upon maintaining the good conservation status of the population and consider certain uses

of intertidal habitats as important indicators of status. It is concluded that the activities proposed in areas

that potentially overlap with otter habitat do not pose a threat to the conservation status of this species.

The aspect of the culture activities that could potentially disturb the Harbour seal status relates to

movement of people and vehicles within the sites as well as accessing the sites over intertidal areas

and via water. The potential for interaction between aquaculture activities and migrating salmon are

mitigated by the implementation of numerous monitoring and regulatory protocols. These management

actions serve to minimize the impact of disease and parasites from the finfish cage structures.

Threshold levels are applied which if exceeded are subject to a variety of management actions which

are designed to minimize risk to both cultured stock and wild fish species.

Conclusion and Recommendation - Aquaculture Activities: It is acknowledged in this assessment

that the favourable conservation status of the Harbour seal (Phoca vitulina) has been achieved given

current levels of aquaculture production within the SAC. On this basis, the current levels of licenced

aquaculture (existing and renewals) are considered non-disturbing to harbour seal conservation

features. It is anticipated that new applications will also result in no disturbances.The aquaculture

activities proposed do not pose a threat to otter and salmon in the Clew Bay Complex SAC.

12 SAC Fisheries Risk Assessment Concluding Statement and Recommendations

There were 26 vessels fishing in the Clew Bay area in 2011. Not all 26 vessels fish within the SAC. At

least 15 fish species are targeted across 11 metiers (gear_target species combination). Gears used

include shrimp pots, lobster creels, top entry pots, prawn pots, dredges, tangle nets, trammel nets, gill

nets, bottom trawls, mid-water trawls, various forms of hooks and lines and hand gathering. Individual

operators may target different species in different seasons.

12.1 Habitats

Other than hand gathering activity no fisheries overlapped qualifying interest 1140 (mud and sand flats

not covered by water at low tide)

Fisheries overlap with a number of marine communities within qualifying interest 1160 (Large Shallow

inlet and bay) and 1170 (Reef). Cumulative impacts are possible, probable or highly likely in 6 cases.

These interactions need to be managed to reduce the risk to the conservation objectives

o Scallop dredging in Zostera

o Scallop dredging in faunal or Laminaria reef

o Potting for shrimp in Maerl communities

100

o Dredging for oyster on Zostera

o Dredging for oyster on Maerl

o Dredging for oyster on faunal or Laminaria reef

Non cumulative seasonal disturbance is assessed as possible or probable in the following interactions

o Potting for shrimp on Zostera

o Potting for shrimp on faunal or Laminaria reef

o Potting for crab/lobster on faunal or Laminaria reef

o Dredging for scallop on sandy mud with polychaetes and bivalves community complex

o Dredging for scallop in fine sand dominated N. cirrosa community

o Dredging for oyster on sandy mud with polychaetes and bivalves community complex

o Hand gathering on reefs

12.2 Species

Considering the 3 pressures (by-catch, prey depletion, disturbance) posed by fishing activity on Harbour

seal, otter and salmon although population level effects are unlikely in any species sub-lethal or lethal

effects on individuals in the population is possible or probable in the following cases.

o By-catch of Harbour Seal in large mesh tangle nets in the site or to the west of the site.

Other nets may also pose a risk (possible)

o By-catch of Otter in lobster creels in the site (unlikely)

o Depletion of prey resources available to Harbour Seal resulting from pelagic fishing

(possible)

At current levels of activity however these fisheries-species interactions are unlikely to pose a significant

risk to Harbour Seal or Otter populations.

101

13 References

ABPMer. 2013a. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report VIII: Vegetation dominated communities (Saltmarsh and Seagrass). Report No. R. 2053 for Marine Institute, Ireland.

ABPMer. 2013b. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report VI: Biogenic reefs (Sabellaria, Native oyster, Maerl). Report No. R. 2068 for Marine Institute, Ireland.

ABPMer. 2013c. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report I: Intertidal and Subtidal Muds. Report No. R. 2069 for Marine Institute, Ireland.

ABPMer. 2013d. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report II: Intertidal and Subtidal Sands. Report No. R. 2070 for Marine Institute, Ireland.

ABPMer. 2013e. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report III: Intertidal and Subtidal muddy sands and sandy muds. Report No. R. 2071 for Marine Institute, Ireland.

ABPMer. 2013f. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report IV: Intertidal and Subtidal mixed sediments. Report No. R. 2072 for Marine Institute, Ireland.

ABPMer. 2013g. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report IV: Intertidal and Subtidal coarse sediments. Report No. R. 2073 for Marine Institute, Ireland.

ABPMer. 2013h. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report VII: Intertidal and Subtidal reefs. Report No. R. 2074 for Marine Institute, Ireland.

Allen, S.G., Ainley, D.G., Page, G.W., & Ribic, C.A. (1984) The effect of disturbance on harbor seal haul out patterns at Bolinas Lagoon,California. Fishery Bulletin, 82(3), 493-500.

Anon., 1996. Making a new beginning in salmon management. Report of the Salmon Management Task Force. Government Publications, Molesworth street, Dublin. 68pp.

Anon. Department of the Marine and Natural Resources 2000. Monitoring Protocol No. 3 Offshore Finfish Farms – Sea Lice Monitoring and Control, May 2000. 7pp. Department of the Marine & Natural Resources Dublin, Ireland.

Anon., 2008. Department of Agriculture Fisheries & Food 2008. A strategy for improved pest control on Irish salmon farms. May 2008. 51pp. Ireland.

Aquaculture Stewardship Council. 2012. ASC Salmon Standard. Version1.0 June 2012. 103pp

Barber, B.J. 1996. Impacts of Shellfish introductions on local communities. In Exotic species workshop: issues relating to aquaculture and biodiversity. Edited by J. Pedersen. MIT Sea Grant College Program (MITSG 96-15), Cambridge. pp. 18-21.

Copley, L., Tierney, T. D., Kane, F., Naughton, O., Kennedy, S., O’Donohoe, P., Jackson, D. & McGrath, D., 2005. Sea lice, Lepeophtheirus salmonis and Caligus elongatus, levels on salmon returning to the west coast of Ireland, 2003. Journal of the Marine Biological Association of the U. K., 85, 87-92.

Copley L, O'Donohoe P, Kennedy S, Tierney D, Naughton O, Kane F, Jackson D & McGrath D 2007. Lice infestation pressures on farmed Atlantic salmon smolts (Salmo salar L.) in the west of Ireland following a SLICE (0.2% emamectin benzoate) treatment. Fish Veterinary Journal 9, pp 10–21.

Cosgrove, R., Cronin, M., Reid, D, Gosch, M., Sheridan, M., Chopin, N. and Jessop, M. 2013. Seal depredation and bycatch in set net fisheries in Irish waters. Fisheries Resource Series, Vol. 10. BIM, DunLaoghaire, Co. Dublin, 38pp.

102

Crosby, M. P. & L. D. Gale. 1990. A review and evaluation of bivalve condition index methodologies with a suggested standard method. J Shellfish Res 91:233-237.

Becker, B.H., D.T. Press, and S.G. Allen. 2009. Modeling the effects of El Niño, density-dependence, and disturbance on harbor seal (Phoca vitulina) counts in Drakes Estero, California: 1997-2007. Marine Mammal Science 25(1):1-18.

Becker, B.H., D.T. Press, and S.G. Allen. 2011. Evidence for long-term spatial displacement of breeding and pupping harbour seals by shellfish aquaculture over three decades. Aquatic conservation: Marine and Freshwater Ecosystems 21: 247-260

Bergman, M.J.N. and vanSantbrink, J.W. 2000. Mortality in megafaunal benthic populations caused by trawl fisheries on the Dutch continental shelf in the North Sea 1994. ICES Journal of Marine Science 57(5), 1321-1331.

BIM (1997) The Physical Interaction between grey seals and fishing gear. An Bord Iascaigh Mhara Report to the European Commission, DG XIV. Ref PEM/93/06

BIM (2001) Grey Seal interactions with fisheries in Irish coastal waters. Report to the European Commission, DG XIV

Borja, A., Franco, J. & Pérez, V. 2000. A marine biotic index of establish the ecological quality of soft-bottom benthos within European estuarine and coastal environments. Marine Pollution Bulletin. 40: 1100 – 1114.

Bouchet VMP, Sauriau P-G. 2008. Influence of oyster culture practices and environmental conditions on the ecological status of intertidal mudflats in the Pertuis Charentais (SW France): a multi-index approach. Marine Pollution Bulletin 56: 1898-1912

Brasseur, S. & Fedak, M. (2003) Habitat use of harbour seals in relation to recreation, fisheries and large infra-structural works. In: Managment of North Sea Harbour and Grey Seal Populations. Common Wadden Sea Secretariat, Ecomare, Texel, The Netherlands.

Carlton, J.T. 1989. Man's role in changing the face of the ocean: biological invasions and implications for conservation of near-shore environments. Conserv. Biol. 3: 265-273.

Carlton, J.T. 1999. Molluscan invasions in marine and estuarine communities. Malacologia 41: 439-454.

Cordes, L.S. et al (2011). Long-term patterns in harbour seal site-use and the consequences for managing protected areas. Animal Conservation, 14(4), 430-438.

Cranford, Peter J., Pauline Kamermans, Gesche Krause, Alain Bodoy, Joseph Mazurié, Bela Buck, Per Dolmer, David Fraser, Kris Van Nieuwenhove, Francis X. O’Beirn, Adoración Sanchez-Mata, Gudrun G. Thorarinsdóttir, and Øivind Strand. 2012. An Ecosystem-Based Framework for the Integrated Evaluation and Management of Bivalve Aquaculture Impacts. Aquaculture Environment Interactions. 2:193-213

Derraik, J.G.B. 2002. The pollution of the marine environment by plastic debris: A review. Marine Pollution Bulletin 44:842-852.

Duck, C. and Morris, C. 2012. An aerial survey of harbour seals in Ireland: Part 1: Lough Foyle to Galway Bay Aug-Sept 2012.Report by SMRU, University of St. Andrews to NPWS

Finstad, B., F. Kroglund, R. Strand, S.O. Stefansson, P.A. Bjorn, B.O. Rosseland, T.O. Nilsen and B. Salbu, 2007. Salmon lice or suboptimal water quality – Reasons for reduced postsmolt survival? Aquaculture 273, 374-383.

Fletcher, W.J. 2005. The application of qualitative risk assessment methodology to prioritize issues for fisheries management. ICES Journal of Marine Science, 62, 1576-1587.

Fletcher, W. et al (2002).National ESD reporting framework for Australian fisheries. The ‘How To’ guide for wild capture fisheries. FRDC Project, 2000/145, Canberra, Australia, 120pp.

Forrest, B.M., Keeley, N.B., Hopkins, G.H. 2009. Synthesis of the Ecological Effects of Intertidal Oyster Aquaculture. Cawthron Report No. 1476.

103

Friedland, K.D., L.P. Hansen, D.A. Dunkley and J.C. MacLean, 2000. Linkage between ocean climate, post-smolt growth and survival of Atlantic salmon (Salmo salar L.) in the North Sea area. ICES Journal of Marine Science 57,419-429.

Friedland, K.D., G. Chaput and J. MacLean, 2005. The emerging role of climate in post-smolt growth of Atlantic salmon. ICES Journal of Marine Science 62, 1334-1349.

Hall, K., Paramor, O.A.L., Robinson L.A., Winrow-Giffin, A., Frid C.L.J., Eno, N.C., Dernie, K.M., Sharp, R.A.M., Wyn, G.C.& Ramsay, K. 2008. Mapping the sensitivity of benthic habitats to fishing in Welsh waters- development of a protocol. CCW [Policy Research] Report No: [8/12], 85pp.

Hiddink, J.G., Jennings, S. and Kaiser, M.J. 2007. Assessing and predicting the relative ecological effects of disturbance on habitats with different sensitivities. Journal of Applied Ecology, 44, 405-413.

Jackson, D. and Minchin, D. 1993. Lice infestations of farmed salmon in Ireland. In: Boxshall, G.A. and Defaye, D. (Eds.), Pathogens of wild and farmed fish: sea lice, Ellis Horwood Ltd., London.

Jackson, D., Deady, S., Leahy, Y., & Hassett, D. 1997. Variations in parasitic caligid infestations on farmed salmonids and implications for their management. ICES Journal of Marine Science. 54: 1104 -1112.

Jackson, D., D. Hassett, S. Deady, Y. Leahy, 2000. Lepeophtheirus salmonis (Copepoda: Caligidae) on farmed salmon in Ireland. Contributions to Zoology. 69, 71-77.

Jackson D., Hassett D. & Copley, L. 2002. Integrated lice management on Irish Salmon farms. Fish Veterinary Journal, (6) 28-38.

Jackson D, Cotter D, O’Maoileidigh N, O’Donohoe P, White J, Kane F, Kelly S, McDermott T, McEvoy S, Drumm A, Cullen A & Rogan G 2011. An evaluation of the impact of early infestation with the salmon louse Lepeophtheirus salmonis on the subsequent survival of outwardly migrating Atlantic salmon, Salmo salar L., smolts. Aquaculture 320, 159-163. http://dx.doi.org/10.1016/j.aquaculture.2011.03.029

Jackson D, O'Donohoe P, McDermott T, Kane F, Kelly S & Drumm A 2013. Report on Sea Lice Epidemiology and Management in Ireland with Particular Reference to Potential Interactions with Wild Salmon (Salmo salar) and Freshwater Pearl Mussel (Margaritifera margaritifera) Populations. Irish Fisheries Bulletin No 43, Marine Institute. http://hdl.handle.net/10793/893

Jackson, D., F. Kane, P. O’Donohoe, T. Mc Dermott, S. Kelly, A. Drumm and J. Newell 2013. Sea lice levels on wild Atlantic salmon returning to the Coast of Ireland. Journal of fish Diseases, 36(3) 293-298.

Jansen, J., Bengtson, J., Boveng, P., Dahle, S., & Ver Hoef, J. (2006). Disturbance of harbor seals by cruise ships in Disenchantment Bay Alaska: an investigation at three temporal and spatial scales., Rep. No. ASFS Processed Report 2006-02. Alaska Fisheries Science Center.

Johnson, A. & Acevedo-Gutierrez, A. (2007) Regulation compliance by vessels and disturbance of harbour seals (Phoca vitulina). Canadian Journal of Zoology, 85, 290-294.

Johnson, D. 2008. Environmental indicators: Their utility in meeting the OSPAR Convention's regulatory needs. ICES Journal of Marine Science 65:1387-1391.

Jones, S.R.M., 2009. Controlling salmon lice on farmed salmon and implications for wild salmon. Perspectives in Agriculture, Veternary Science, Nutrition and Natural Resources 4 no. 048, 13pp.

Kochmann J, Carlsson J, Crowe TP, Mariani S (2012) Genetic evidence for the uncoupling of local aquaculture activities and a population of an invasive species—a case study of Pacific oysters (Crassostrea gigas). Journal of Hereditary 103:661–671

Kochmann, J. F. O’Beirn, J. Yearsley and T.P. Crowe. 2013. Environmental factors associated with invasion: modeling occurrence data from a coordinated sampling programme for Pacific oysters. Biological Invasions DOI 10.1007/s10530-013-0452-9.

Lelli, B. & Harris, D.E. (2001) Human disturbances affect harbour seal haul-out behaviour: can the law protect these seals from boaters? In: Macalester Environmental Review, pp. 1-16.

http://dx.doi.org/10.1016/j.aquaculture.2011.03.029

http://hdl.handle.net/10793/893

104

Lewis, T.M. & Mathews, E.A. (2000). Effects of human visitors on the behaviour of harbour seals (Phoca vitulina richardsi) at McBride Glacier Fjord, Glacier Bay National Park. University of Alaska Southeast & Glacier Bay National Park, Juneau & Gustavus, Alaska.

National Research Council, 2009. Shellfish Mariculture in Drakes Estero, Point Reyes National Seashore, California. National Academy Press, Washington, DC.

National Research Council, 2010. Ecosystems Concepts for Sustainable Bivalve Culture. National Academy Press, Washington, DC.

Nelson, Marcy Lynn, "Interactions between Seals and Atlantic Salmon Aquaculture in Maine" (2004). Electronic Theses and Dissertations. Paper 1537 - http://digitalcommons.library.umaine.edu/etd/1537

NPWS. 2010. Harbour Seal population monitoring 2009-2012: Report No. 1 – Report on a pilot monitoring study carried out in southern and western Ireland. Department Arts, Heritage and the Gaeltacht. June 2010 11pp

NPWS. 2011a. Clew Bay complex SAC (001482): Conservation Objectives supporting document – marine habitats and species. Department Arts, Heritage and the Gaeltacht. Version 1 (June 2011); 23pp.

NPWS. 2011b. Clew Bay complex SAC (001482): Conservation Objectives. Department Arts, Heritage and the Gaeltacht. Version 1 (June 2011); 24pp.

NPWS. 2011c. Harbour Seal pilot monitoring Project, 2010. Department Arts, Heritage and the Gaeltacht. June 2011. 15pp

NPWS. 2012. Conservation Objectives for Donegal Bay (Murvagh) SAC (00133). Version 1.0. Department Arts, Heritage and the Gaeltacht. Version 1 (9 July, 2012); 13pp.

NPWS. 2012a. Harbour Seal pilot monitoring Project, 2011. Department Arts, Heritage and the Gaeltacht. January 2012 15pp

Mag Aoidh, R. 2011. Reproduction of Crassostrea gigas in Irish Waters: An analysis of gametogenesis and condition comparing tidal location and ploidy level. MSc Thesis, University College Dublin, Ireland. 84pp.

McKindsey, CW, Landry, T, O’Beirn, FX & Davies, IM. 2007. Bivalve aquaculture and exotic species: A review of ecological considerations and management issues. Journal of Shellfish Research

26:281-294.

O’Beirn, F.X., C. W. McKindsey, T. Landry, B. Costa-Pierce. 2012. Methods for Sustainable Shellfish Culture. 2012. pages 9174-9196 In: Myers, R.A. (ed.), Encyclopedia of Sustainability Science and Technology. Springer Science, N.Y.

O’Donohoe P, Kane F, Kelly S, McDermott T, Drumm A & Jackson D 2013. National Survey of Sea lice (Lepeophtheirus salmonis Krøyer and Caligus elongatus Nordmann) on Fish Farms in Ireland - 2012. Irish Fisheries Bulletin No 41, Marine Institute. http://oar.marine.ie/handle/10793/861

O’Maoileidigh, N., P. McGinnity, E. Prévost, E.C.E. Potter, P. Gargan, W.W. Crozier, P. Mills and W. Roche, 2004. Application of pre-fishery abundance modeling and Bayesian hierarchical stock and recruitment analysis to the provision of precautionary catch advice for Irish salmon (Salmo salar L.) fisheries. ICES Journal of Marine Science 61, 1370-1378.

Perry, E.A., Boness, D.J., & Insley, S.J. (2002) Effects of sonic booms on breeding grey seals and harbour seals on Sable Island, Canada. J. Acoust. Soc. Am., 111(1), 599-609.

Roberts, C., Smith, C., Tillin, H., Tyler-Walters, H. 2010. Evidence. Review of existing approaches to evaluate marine habitat vulnerability to commercial fishing activities. Report SC080016/R3. Environment Agency,UK. ISBN 978-1-84911-208-6.

Seuront, L.J.J. & Prinzivalli, P. (2005) Vulnerability of harbour seals, Phoca vitulina, to transient industrial activities in the Strait of Dover. Journal of the Marine Biological Association UK, 85, 1015-1016.

Sevatdal, S., Copley, L., Wallace, C., Jackson, D. and T. Horsberg 2005. Monitoring of the sensitivity of sea lice (Lepeophtheirus salmonis) to pyrethroids in Norway, Ireland and Scotland using bioassays and probit modelling. Aquaculture 244:19-27.

http://oar.marine.ie/handle/10793/861

105

Shellfish Pollution Reduction Programme - As required by Article 5 of the Shellfish Water Directive 2006/113/EC and Section 6 of the Quality of Shellfish Waters Regulations, 2006 (S.I. No. 268 of 2006) - Characterisation Report Number VI

Suryan, R.M. & Harvey, J.T. (1999) Variability in reactions of Pacific harbor seals, Phoca vitulina richardsi, to disturbance. Fishery Bulletin, 97, 332-339.

Tebble, N. 1976. British bivalve seashells. Royal Scottish Museum. 212pp

Tillin, H.M., Hiddink, J.G., Jennings, S and Kaiser, M.J. 2006. Chronic bottom trawling alters the functional composition of benthic invertebrate communities on a sea basin scale. Marine Ecology progress Series, 318, 31-45.

Twelves, J. (1983). Otter mortalities in lobster creels. Journal of Zoology, 201, 585-588.

Wade, P.R. 1998. Calculating limits to the allowable human-caused mortality of cetaceans and pinnipeds. Marine Mammal Science, 14(1), 1-37.

Watson-Capps, J.J. & Mann, J. (2005) The effects of aquaculture on bottlenose dolphin (Tursiops sp.) ranging in Shark Bay, Western Australia. Biological Conservation, 124, 519-526.

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