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© British Crown Copyright 1998
Impacts of fishing on marine benthic habitats
Michel J. Kaiser1, Jeremy S. Collie2, Stephen J. Hall3, Simon Jennings4, Ian R. Poiner5
1School of Ocean Sciences, University of Wales-Bangor, Menai Bridge, Anglesey, LL59 5EY, UK2Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882, USA
3Australian Institute for Marine Science, PMB 3, Townsville MC, Queensland 4810, Australia 4The Centre for Environment, Fisheries & Aquaculture Science, Lowestoft Laboratory, Lowestoft, NR33 0HT, UK
5CSIRO Division of Marine Research, PO Box 120, Cleveland, Queensland 4163, Australia
Impacts of fishing on marine benthic habitats
Michel J. Kaiser1, Jeremy S. Collie2, Stephen J. Hall3, Simon Jennings4, Ian R. Poiner5
1School of Ocean Sciences, University of Wales-Bangor, Menai Bridge, Anglesey, LL59 5EY, UK2Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882, USA
3Australian Institute for Marine Science, PMB 3, Townsville MC, Queensland 4810, Australia 4The Centre for Environment, Fisheries & Aquaculture Science, Lowestoft Laboratory, Lowestoft, NR33 0HT, UK
5CSIRO Division of Marine Research, PO Box 120, Cleveland, Queensland 4163, Australia
School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
Demersal fishing gearsBeam trawl rigged for clean ground
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
Scale of disturbance and recovery rateScale of disturbance and recovery rate
Patch size
10 mm² 1 m² 100 m² 108 m²
10 y5y1y
1 mo
1 day macrofauna
eiderrays
walrus grey whales
anoxiaIce scour
fishing
Hydraulic dredging
fishing
Rec
ove
ry t
ime
hurricanes
tidal currents
bait digginghurricanes
© British Crown Copyright 1998
The importance of Connell’s intermediate disturbance hypothesis
The importance of Connell’s intermediate disturbance hypothesis
School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
Less
dis
turb
ance
High
Low
Diversity
Disturbances frequentSoon after a disturbanceDisturbance large
Disturbances frequentSoon after a disturbanceDisturbance large
InfrequentInfrequentLong after a disturbanceLong after a disturbanceDisturbance smallDisturbance small
InfrequentInfrequentLong after a disturbanceLong after a disturbanceDisturbance smallDisturbance small
Grossly stressed communityClimax community
Increasing disturbance
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
WHAT CAN WE LEARN WHAT CAN WE LEARN FROM FROM
EXPERIMENTS?EXPERIMENTS?
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
No. spp No. indiv. Shannon’s H___________________________________
Stable sedimentunfished 67±3*** 335±18** 29±2***fished 31±3 196±32 15±1
Mobile sedimentunfished 29±5 ns 59±11 ns 21±4 ns
fished 27±5 98±27 16±3
Infaunal responsesto fishing disturbance
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
Intertidal Dredging
Scallop Dredging
Intertidal Raking
Beam Trawling
Otter Trawling
Eastern Australia
Northern Europe
East North America
New Zealand
South Australia
-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6
-1.5 -1.0 -0.8 0.0
LOCALITY
GEAR
Gravel
Muddy Sand
Biogenic
Sand
Mud
AnthozoaMalacostracaOphiuroidea
HolothuroideaMaxillopodaPolychaeta
GastropodaEchinoidea
DesmospongiaAsteroidea
Oligochaeta
Bivalvia
-0.9 -0.8 -0.7
-1.4 -1.2 -1.0 -0.8 -0.6 -0.4
CLASS
HABITAT
RESPONSE RESPONSE RESPONSE RESPONSE
META-ANALYSISMETA-ANALYSIS
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
55
00
-5-50 100 5000 100 500
mud/sand mud/sand
sandsand biogenicbiogenic
Rel
ativ
e re
spon
seR
elat
ive
resp
onse
THE RECOVERY TRAJECTORY OF DIFFERENT HABITATSTHE RECOVERY TRAJECTORY OF DIFFERENT HABITATS
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
Limaria hians nests previously undredged
0
1
2
3
befo
re
befo
re
sum
94
win
95
sum
95
win
96
sum
96
win
97
sum
97
win
98
Time after dredging (years)
Num
ber
m-2
test plot
control
Pre-dredge1 2 3 40
**
*
* **
**
** *
*
*
School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
Photograph: Jason Hall-Spencer
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
ENERGY SUBSIDIESFishing can also alter habitat by inducing population changes in‘habitat engineering species’
0
1
2
3
4
5
6
-1 -0.5 0 0.5 1
log (proportion of seabed area swept by beam trawls per year)
log (
starf
ish c
atc
h n
um
bers
)
p < 0.005
Log proportion seabed swept/yr
star
fish
cat
ch n
um
ber
s
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
TESTING PREDICTIONSTESTING PREDICTIONSAT A REALISTICAT A REALISTIC
SCALESCALE
4 30’Wo4 00’Wo
50 16’No
Legend
Low fishing effort. Area 2 - No trawling permitted,Areas 5 & 8 - Pots only all year.Medium fishing effort. Areas 4 & 7 - Seasonal trawling permitted between 15th January & 1st July.High fishing effort. Areas 1, 3 & 6 - Trawling all year round.
Figure 1.
School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
PlymouthSound
Pots all year
Trawling Jan - July7
8
6
45
3
1
2
Salcombe
Towed gear all year
Pots all year
LOW EFFORTLOW EFFORT
MEDIUM EFFORTMEDIUM EFFORT
HIGH EFFORTHIGH EFFORT
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
Area 5, 4 and 3Area 5, 4 and 3
Mean biomass of selected speciesMean biomass of selected species
Fishing effortFishing effortLowLow MedMed HighHigh
HydroidsHydroids 720720 121121 259259Dead men’s fingersDead men’s fingers 16061606 22 1414Dog cockleDog cockle 1010 1212 00Sea potatoSea potato 3232 77 33PsammechinusPsammechinus 8585 33 11
4 30’Wo4 00’Wo
50 16’No
Legend
Low fishing effort. Area 2 - No trawling permitted,Areas 5 & 8 - Pots only all year.Medium fishing effort. Areas 4 & 7 - Seasonal trawling permitted between 15th January & 1st July.High fishing effort. Areas 1, 3 & 6 - Trawling all year round.
Figure 1.
School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
PlymouthSound
Pots all year
Trawling Jan - July7
8
6
45
3
1
2
Salcombe
Towed gear all year
Pots all year
LOW EFFORTLOW EFFORT
MEDIUM EFFORTMEDIUM EFFORT
HIGH EFFORTHIGH EFFORT
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
1 10 100
0
10
20
30
40
50
60
70
80
90
100
1 10
0
10
20
30
40
50
60
70
80
90
100
1 10 100
0
10
20
30
40
50
60
70
80
90
100
Species rank
Low fishing disturbance
high fishing disturbance
intermediate fishing disturbance
biomasscurve
abundancecurve
Gear restriction management regimes help to conserveGear restriction management regimes help to conservelarger, emergent seabed faunalarger, emergent seabed fauna
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
CAN WE IMPLEMENT CAN WE IMPLEMENT MANAGEMENT SYSTEMSMANAGEMENT SYSTEMSTHAT ARE USEFUL IN A THAT ARE USEFUL IN A
CONSERVATION CONTEXT?CONSERVATION CONTEXT?
-76 -74 -72 -70 -68 -66Longitude
36.0
37.3
38.6
39.9
41.2
42.5
Latit
ude
36.0
37.3
38.6
39.9
41.2
42.5
Latitude
-76 -74 -72 -70 -68 -66Longitude
-76 -74 -72 -70 -68 -66Longitude
36.0
37.3
38.6
39.9
41.2
42.5
Latit
ude
Fishing Time 1998
School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
1998Fishing Time hours/nm^2blue <2green 2-9yellow 9-44red >44
-76 -74 -72 -70 -68 -66Longitude
36.0
37.3
38.6
39.9
41.2
42.5La
titud
e
36.0
37.3
38.6
39.9
41.2
42.5
Latitude
-76 -74 -72 -70 -68 -66Longitude
-76 -74 -72 -70 -68 -66Longitude
36.0
37.3
38.6
39.9
41.2
42.5La
titud
e
Fishing Time 1999
School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
1999Fishing Time hours/nm^2blue <2green 2-9yellow 9-44red >44
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
0
10
20
30
40
50
60
10 30 50 70 90 110 130 150 170
Shell height (mm)
Nu
mb
er
pe
r to
w
Outside closed area
Inside closed area
Effects of large-scale fishery closure off the eastern coastof the United States - secondary benefits for scallops
© British Crown Copyright 1998School of Ocean Sciences, University of Wales-BangorSchool of Ocean Sciences, University of Wales-Bangor
ConclusionsConclusions
Areas subject to fishing with towed bottom gearAreas subject to fishing with towed bottom gearare dominated by lower biomass organisms andare dominated by lower biomass organisms andhave less surface structurehave less surface structure
Areas exploited using pot gear have high biomass Areas exploited using pot gear have high biomass communities with greater surface reliefcommunities with greater surface relief
It appears that with the application of common It appears that with the application of common sense we can “have our cake and eat it”sense we can “have our cake and eat it”
Areas closed to towed fishing gear can still beAreas closed to towed fishing gear can still beexploited while conserving the environmentexploited while conserving the environment