NIFCA 2015 V-notching report
NIFCA V-notching Report
2016
Report Written By: Vicky Rae and Natalie Wallace
Northumberland Inshore Fisheries and Conservation Authority 8 Ennerdale Road Blyth NE24 4RT Tel: 01670 797676 Email: [email protected] Website: www.nifca.gov.uk
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NIFCA 2015 V-notching report
Contents
1. Introduction
1.1 Conservation Management Tool…………………………………………………… 1
1.2 Biology of a lobster……………………………………………………………………….. 2
1.3 History of V-notching scheme in Northumberland District……………. 2
2. V-notching Programme 2015
2.1 Programme Review……………………………………………………………………….. 3
2.2 Overview……………………………………………………………………………………….. 3
2.3 Releases………………………………………………………………………………………… 3
2.4 Purchase of lobsters……………………………………………………………………… 6
3. Stock Assessment Survey……………………………………………………………………. 7
4. Appendix……………………………………………………………………………………………..9
5. References ……………………………………………………………………………………11
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NIFCA 2015 V-notching report
1. Introduction
1.1 Conservation Management Tool
V-notching schemes have been implemented globally and are a widely recognised fishery
management tool by both scientific (Gunning 2012) and fishing (Acheson et al. 2010)
communities to help sustain lobster fisheries. Their objective is to maintain a healthy
reproductive population in order to provide continual recruitment of lobster offspring to the
stock, thus creating a sustainable industry and profitable fishery.
The scheme involves removing a V shape piece of exoskeleton from the Uropod, the inner
tail flap of female lobsters of reproductive size (usually above the minimum landing size
87mm carapace length).
While a female lobster retains this v-notch she is protected from the local fishery, as the NIFCA byelaw 3. Crustacea Conservation (fig 1), makes it illegal to land her within the NIFCA district.
Fig1. NIFCA byelaw 3. Crustacea Conservation
Prohibitions relating to Lobsters
2. A person must not fish for, remove, take, retain, store, carry, transport, land or offer for sale:
(a) a ‘v’ notched lobster;
(b) a mutilated lobster;
(c) a soft shelled lobster; or
(d)
a detached part of a lobster which cannot be measured in accordance with Annex
XIII of Council Regulation (EC) 850/98 of 30 March 1998 for the conservation of
fishery resources through technical measures for the protection of juveniles of
marine organisms.
V-notching a female
lobster
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NIFCA 2015 V-notching report
1.2 Biology of a Lobster
The mechanism of the v-notching scheme works with the biology and growth cycle of a
lobster. Lobsters incrementally grow throughout their lives, in a process known as moulting;
the shedding of their hard existing exoskeleton (outer shell). This process begins when a
lobster absorbs water into their tissues to cause their body to swell and split their existing
exoskeleton. Once free of the old exoskeleton a new softer exoskeleton is revealed having
formed beneath the old. This is then stretched before it
hardens as the lobster continues to absorb water into its
body tissues to generate new tissue growth. This process
can take a few hours up to several weeks and each moult
will increase their carapace length by approximately 7mm
(Agnalt et al. 2007). Younger lobsters moult more
frequently than older adults and at about 85mm (six years)
carapace length onwards, a lobster will moult annually or
every other year. This means that the lobster will retain
the v-notch in her tail for approximately one to two
moults/ years, giving her the chance to successfully
complete a breeding cycle to release eggs.
The time at which lobsters reproduce is dependent on the moulting cycle of the female, as mating occurs between a hard shelled male and a soft shelled (newly moulted) female. Once a female bears eggs she is unable to moult again until they have hatched (about nine months), as this would cause her to lose her eggs. Generally, the majority of lobsters will breed in early summer and depending on
the size of the female, she can produce between 3, 000 (carapace length ~87mm) to 30, 000 eggs (carapace length ~150mm). Once hatched the survival rate to the postlarvae stage is 0.005% (www.nationallobsterhatchery.co.uk).
1.3 History of V-notching scheme in Northumberland district
NIFCA adopted a v-notching scheme in 2000 (then Sea Fisheries Committee), which has
been carried out every subsequent year since, releasing approximately 1,000 females back
into the sea each year. A total of 19,450 females (including 2016 scheme) have been v-
notched and released by the Authority throughout the NIFCA district since the scheme
began in 2000.
The Authority has always received positive support and feedback of the scheme from the
fishing industry, who continue to report large numbers of juvenile lobsters (under 87mm) on
the fishing grounds. Furthermore they have commented on how they have observed an
A female lobster carrying eggs (a
berried hen)
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NIFCA 2015 V-notching report
increase in juvenile abundance increased in recent years, which many attribute to the v-
notching scheme (Duffill-Telsnig 2014).
2. 2015 V-notching Programme
2.1 Programme Review
The 2015 revision of the NIFCA byelaws, No. 3 Crustacea Conservation Byelaw, paragraph 1
(o), now quantifies a minimum v-notch depth of 5mm to be present in the female tail to
protect her from the fishery. This potentially could reduce the amount of time a female is
protected from the fishery, as previously a lack of clarity meant a precautionary approach
was undertaken to ensure compliance to the v-notching byelaw. Furthermore research has
shown that a higher proportion/ percentage of females reproduce every other year (as
opposed to annually) (Agnalt et al. 2007). These two factors combined could reduce the
conservation effectiveness of the v-notching scheme by reducing the amount of time female
lobsters are protected and the number of eggs released during this time.
As a result additional methods were introduced into the programme to increase the number
of individuals v-notched, the effectiveness of the scheme and therefore the number of eggs
released by; purchasing lobsters directly from working fishing vessels at sea and supplying
fishermen with v-notch pliers. Fishermen were also supplied with log sheets to record the
number of lobsters they v-notched and to provide more information on levels of v-notching
in the district.
2.2 Overview
The 2016 v-notching scheme began on the 27th June and finished on the 21th September. A
total of 1176 female lobsters were v-notched and released by the Authority throughout the
Northumberland district. It is important to note that the some fishermen voluntarily v-notch
lobsters throughout the district, however releases by fishermen will have gone unrecorded.
2.3 Releases
The v-notched lobsters are distributed throughout the district within the following sectors.
The number of female lobsters v-notched and released (brought from wholesalers)
throughout each of these sectors is displayed in Graph 1 from 2006 to 2016.
SECTOR 1 : Tyne → Wansbeck
SECTOR 2 : Wansbeck → Amble
SECTOR 3 : Amble → Embleton
SECTOR 4 : Embleton → North of Farne Islands
SECTOR 5 : North of Farnes Island’s → Scottish Border
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NIFCA 2015 V-notching report
Map of sectors within NIFCA district
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4
3
2
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NIFCA 2015 V-notching report
Graph.1 shows the distribution of v-notched lobsters (brought and released through wholesalers) by the Authority throughout the five sectors since 2006 to present day.
0
500
1000
1500
2000
2500
3000
3500
1 2 3 4 5
No
. of
Re
leas
es
Sectors
Total number of releases throughout the Northumberland district from 2006 - 2016
2016
2015
2014
2013
2012
2011
2010
2009
2008
2007
2006
2,368 2,416 2,295
2,020
2,727
2,295
2,020
2,295
2,727 2, 295 2,416 2,368
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NIFCA 2015 V-notching report
2.4 Purchase of Lobsters
During this year’s scheme lobsters were bought from wholesalers and directly from
fishermen at sea. Prices varied throughout the season from £10 to £13.50 per kilogram, with
the total payment for 1176 lobsters amounting to £10,692.25. The number of lobsters
purchased depended on the number available, which was often determined by the weather
and sea state conditions.
Along with the £10, 000 reserved by the Authority for the scheme, we received £740 in
donations from members of the local fishing industry. The Authority is always extremely
grateful to everyone contributed donations to the scheme, for the purchasing of lobster’s to
be v-notched. Without their generous contributions the project would not be able to
operate.
Lobsters bought from Blyth Fish Ltd. and D.R.Collin & Son Ltd. were transported onto PV St
Aidan or Bravo 1 RIB, which then set off from Blyth Boat Club yard (Blyth Fish) and Berwick
(D.R.Collin).
Once on the PV/RIB, they were v-notched and measured at sea, and returned to a location
of suitable habitat. They were released over nine days throughout the districts five sectors
(table 1.). Each release required a minimum of three IFCO officers to carry out the process
and dependant on the site for purchasing and releasing the lobsters, this took between two
to four hours.
Table.1 Purchase details of lobsters brought from wholesalers.
Date Supplier Weight (kg)
No. of Lobsters
Invoice Total
27/06/2016 Blyth Fish Ltd 26 36 £286.00
07/07/2016 Blyth Fish Ltd 45.25 71 £588.25
15/07/2016 Blyth Fish Ltd 34 57 £442.00
27/07/2016 D.R. Collin and Son Ltd 175 222 £1,750.00
12/08/2016 Blyth Fish Ltd 43 66 £473.00
02/09/2016 Blyth Fish Ltd 96.5 137 £1,038.00
09/09/2016 Blyth Fish Ltd 131 209 £1,572.00
16/09/2016 D.R. Collin and Son Ltd 269.5 248 £3,503.50
21/09/2016 Blyth Fish Ltd 77 130 £1,039.50
Total £10,692.25
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NIFCA 2015 V-notching report
Table 2. Distribution of released V-notched lobsters throughout the NIFCA district.
Sector releases
Date 1 2 3 4 5
27.06.2016 36
07.07.2016 71
15.07.2016 57
27.07.2016 222
12.08.2016 66
02/09/2016 137
09/09/2016 44 165
16/09/2016 248
21/09/2016 130
Totals 238 201 267 248 222
3. Stock Assessment Survey
Between March 2014 and March 2016 NIFCA, with the help of local fishermen have been
carried out a Stock Assessment project across the Northumberland district. This involved an
IFCO going to sea on board participating fishing vessels, once a month recording and
measuring every individual lobster hauled from their pots. This data allows us to assess the
health and sustainability of the lobster stocks in our district, providing us with a greater
insight into the size structure of the population and levels of recruitment to the stock.
Part of the information collected is the number of female lobsters (hens) which are v-
notched. This allows the authority to assess the percentage of v-notched females
contributing to the total landable catch of a vessel, in addition to providing an indication of
the population of reproductive potential within the stocks (Tully 2000). Using this data in
combination with the analysis of juvenile (carapace length <87mm) numbers recorded, a
quantifiable index to monitoring the success of the scheme is possible.
Table 3 provides a summary of the data recorded and analysed so far of the composition of
v-notches and female lobsters (hens) in surveyed catches. A full report will be published in
2017.
The rates of v-notching are highest off Seahouses (7.53%) and Holy Island (6.39%) (table 3).
In these areas v-notched lobsters make a significant contribution to the spawning stock
potential and 6-8% is a realistic target for levels of v-notching across the district. This will be
achieved through continuation and improvement of NIFCA’s v-notching scheme as well as
maintaining involvement of fishermen with the scheme through provisions of pliers and on-
going education of the important benefits of v-notching for lobster stocks, and thus the
sustainability of the fishery, within the NIFCA District.
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NIFCA 2015 V-notching report
Photos taken while on Stock Assessment survey on board fishing vessels
Table 3. Summary of data showing the percentage of V-notched lobsters in stock assessment.
Acknowledgements
The Authority is extremely grateful for everyone involved in this project and
would like to express our sincere thanks. Without your help and participation
the v-notching scheme would not be possible or a continued success.
Port No.
V-notched No. hens
>87mm CL
% of hens >87mm CL V-notched
Total no. of male & female lobsters
> 87mm
% of landable catch V-notched
North Shields 5 343 1.46 643 0.78
Amble 29 448 6.47 1056 2.75
Holy Island 25 240 10.42 391 6.39
Seahouses 126 947 13.31 1673 7.53
Craster 14 216 6.48 357 3.92
Berwick 9 190 4.74 363 2.45
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NIFCA 2015 V-notching report
4. Appendix
Annex 1. showing all the size frequency distribution of female lobsters v-notched in 2016.
0
20
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100
1208
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5+
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en
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Carapace Length (mm)
Size Frequency Distribution of Lobsters V-notched and Released
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NIFCA 2015 V-notching report
Annex 2. Lobster V-notch Recording Sheet. Showing total egg development stage and carapace
length of all lobsters v-notched by NIFCA in 2016.
Egg Development
Lobster CL (mm) Black/Green Eyed/Hatched Non-berried Total
87 39 12 51
88 29 9 38
89 40 14 54
90 43 14 57
91 51 10 61
92 82 15 97
93 70 10 80
94 53 13 66
95 45 7 52
96 39 3 42
97 34 6 40
98 27 8 35
99 19 3 22
100 16 1 17
101 23 3 1 27
102 15 2 17
103 16 6 22
104 28 2 30
105 16 1 17
106 11 1 12
107 28 3 31
108 22 3 25
109 16 3 19
110 13 0 13
111 13 1 14
112 16 1 17
113 14 2 16
114 17 1 18
115 16 2 18
116 9 1 10
117 13 2 15
118 17 0 17
119 7 1 8
120 6 0 6
121 9 0 9
122 8 0 8
123 5 1 6
124 5 0 5
125+ 76 8 84
TOTAL 1006 169 1 1176
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NIFCA 2015 V-notching report
5. References
Acheson, J.M & Gardner, R. (2010). ‘The evolution of conservation rules and norms in the Maine
lobster industry’. Ocean & Coastal Management 53:524-534
Agnalt, A., Kristiansen, T.S. & Jᴓrstad, K.E. (2007). ‘Growth, reproductive cycle and movement of
berried European lobsters (Homarus gammarus) in a stock off southwestern Norway’. ICES Journal of
Marine Science, 64: 288-297
Gunning, D. (2012). ‘The Importance of size- fecundity relationships in the management of the
European lobster Homarus gammarus’. Intergrated Aquatic Resources Management Between
Ireland, Northern Ireland and Scotland
Telsnig, J.D. (2014). ‘Final Report: The Effective of v-notching European lobsters in the
Northumberland region’. http://www.nifca.gov.uk/downloads/
Tully, O. (2000). ‘Impact of the v-notch technical conservation measure on reproductive potential in a
lobster (Homarus gammarus L.) fishery in Ireland’. Marine and Freshwater Research. 51
http://www.nationallobsterhatchery.co.uk/whats-it-all-about/education/lobster-biology/
