nifca lobster v-notching report · lobster. lobsters incrementally grow throughout their lives, in...

2017 V-Notching Report

Report Written By: Vicky Rae

Northumberland Inshore Fisheries and Conservation Authority

8 Ennerdale Road

Blyth

NE24 4RT

Tel: 01670 797676

NIFCA V-notching 2017 Report


Contents 1. Introduction ------------------------------------------------------------------------------------------------ 1

1.1 Conservation Management Tool ----------------------------------------------------------------- 1 1.2 Biology of European Lobsters (Homarus gammarus)---------------------------------------- 2 1.3 History of V-notching Scheme in the Northumberland District---------------------------- 2

2. 2017 V-notching Programme--------------------------------------------------------------------------- 3 2.1 Overview------------------------------------------------------------------------------------------------ 3 2.2 Releases------------------------------------------------------------------------------------------------- 3

2.2.1 Scheme Releases-------------------------------------------------------------------------- 3 2.2.2 Other Releases---------------------------------------------------------------------------- 5

2.3 Scheme Finance--------------------------------------------------------------------------------------- 8 2.3.1 Donations----------------------------------------------------------------------------------- 8 2.3.2 Purchase of Lobsters--------------------------------------------------------------------- 9

3. Monitoring of Scheme----------------------------------------------------------------------------------- 9

3.1 Shellfish Permit Returns----------------------------------------------------------------------------- 9 3.2 2014- 2016 Stock Assessment--------------------------------------------------------------------- 12

4. Future of V-notching Scheme-------------------------------------------------------------------------- 13

5. Appendix 1. Size frequency distribution of female lobsters v-notched during 2017 14 2. Lobster V-notching recording sheet, showing egg development stage and carapace

lengths of all lobsters V-notched during 2017

15

6. References--------------------------------------------------------------------------------------------------- 16 Tables

1. Distribution of released V-notched lobsters throughout the NIFCA district---------------------------- 5 2. Purchase details of lobsters bought from wholesalers----------------------------------------------------- 9 3. Summary of data showing the percentage of V-notched lobsters in stock assessment------------- 12

Figures 1. NIFCA Byelaw 3. Crustacea Conservation. Legislation pertaining to the ‘V’- notched lobsters---- 1 2. Map of NIFCA’s Five Sectors--------------------------------------------------------------------------------------- 4 3. Broad-scale habitat map displaying the hard/ soft grounds within NIFCA’s district, with the

locations of the lobster releases. ArcGIS data provided by Natural England (Dec 2016 release) and Latitude and longitude co-ordinates recorded on St. Aidan and Bravo 1-------------------------

6

4. The distribution of v-notched lobsters (brought and released through wholesalers) by the Authority throughout the five sectors since 2000 to present day-----------------------------------------

7

5. Graph showing the total cost spent on purchasing lobsters from wholesalers (and vessels in 2015) each year, 2000 – 2017-------------------------------------------------------------------------------------

8

6. Data taken from in monthly shellfish permit returns. Blue bars represent number of V-notched lobsters recorded by fishermen and the yellow line represents fishing effort (average number of pots hauled x number of days fished) across NIFCA’s five sectors.-------------------------

10

7. Graph showing the standardised re-capture rates of V-notched lobsters across the NIFCA five sectors-------------------------------------------------------------------------------------------------------------------

11

8. Standardised re-capture rates of V-notched lobsters across the NIFCA five sectors----------------- 11


1

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 communities (Acheson et al. 2010) 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 shaped piece of exoskeleton from the Uropod, the inner tail flap (red sections of tail, picture insert below) of female lobsters of reproductive size (usually above the minimum landing size 87mm carapace length).

While a lobster retains this V-notch it is essentially removed from the fishery, legally protected by NIFCA Byelaw 3. Crustacea Conservation (fig 1) from being landed. Revision of the NIFCA byelaws in 2015 provided an additional definition for a V-notched in paragraph 1(o), clarifying the depth limit of the V-notch before they can be landed (fig 1).

V-notching a lobster

Fig. 1 ǀ NIFCA Byelaw 3. Crustacea Conservation. Legislation pertaining to the ‘V’- notched lobsters.

1 (a) ‘mutilated lobster’ means a lobster which is mutilated in such a manner as to obscure a ‘V’-notched lobster

(o) ‘V’ notched lobster’ means a lobster with a notch in the shape of the letter ‘v’ with a depth of at least 5mm in at least one of the inner flaps of the tail fan either side of the main tail flap, with the apex of the ‘v’ positioned inward from the edge of the flap. The depth of the ‘v’ notch is measured vertically from the distal edge of the flap (not including setae) to the apex of the ‘v’.

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; (d) a detached part of a lobster which cannot be measured in accordance with Annex XIII

of Council Regulation (EC) 850/98 of 30th

March 1998 for the conservation of fishery of juveniles of marine organisms.


2

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 20,174 females (including 2017 scheme) have been V-

notched and released by the Authority throughout the NIFCA district.

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

A female lobster carrying eggs

(a berried hen)

http://www.nationallobsterhatchery.co.uk/


3

the fishing grounds. Furthermore they have commented on how they have observed an

increase in juvenile abundance in recent years, which many attribute to the V-notching

scheme (Duffill-Telsnig 2014).

2. 2017 V-notching Programme

2.1 Overview The 2017 V-notching scheme began on the 20th July, with the last release completed on the 8th September. A total of 1012 lobsters were V-notched and released over five days by the Authority throughout the district, 90% of which were egg bearing females. The number released in each sector varied this year in an attempt to target sectors which had in previous years received less releases. 2.2 Releases 2.2.1 Scheme releases V-notched lobsters were distributed throughout the district within the NIFCA sectors one to five (Fig 2). The number of female lobsters V-notched and released (bought from wholesalers) throughout each of these sectors is displayed in Fig X from 2000 to 2017. In previous years the most northern sector five had received fewer releases, due to logistics. This year the Authority undertook these obstacles to ensure the 200 target was obtained for this sector.

Once bought the lobsters were immediately transported onto PV St Aidan or Bravo 1 RIB, at North Shields Fish Quay, Blyth or Eyemouth Harbour. Once on the PV/RIB, they were stored in fish boxes either covered with damp towels or placed in circulating seawater to reduce stress. At a suitable location (over rocky reef habitats) each lobster was measured and V-notched and released. The releases occurred over five days throughout the district’s five sectors (Table 2). 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 ten hours.

Lobsters being transported onto St. Aidan at Blyth harbour


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Fig 2 ǀ NIFCA’s five sectors

5

4

3

2

1

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


5

Table 1 ǀ Distribution of released V-notched lobsters throughout the NIFCA district.

Sector releases

Date 1 2 3 4 5

20.07.2017

61 01.08.2017

148

17.08.2017

91

199 207

31.08.2017 162 08.09.2017

72 72

Totals (1012) 162 224 220 199 207

2.2.2 Other Releases Undocumented V-notching also continues outside the scheme throughout the year, by the local industry and NIFCA. Fishermen voluntarily V-notch lobsters while at sea, in particular large egg bearing females. Research has shown larger females not only to have a higher fecundity rate (producing more eggs) but that these eggs are also more viable, being heavier and developing larger larvae (SundelÖf et al. 2015), which is why they are targeted by fishermen for V-notching. In addition, over 100 adult males and females have been V-notched over the last 12 months by the Authority. The escape gap survey conducted between August 2016 to July 2017 presented an opportunity to V-notch and return lobsters while at sea. Furthermore, throughout the year NIFCA attend events, for which wholesalers supplied one or two lobsters for our display tank as part of our public awareness campaign. At the end of these events, these lobsters were V-notched and returned to sea.

(Above) Carapace length of lobsters being measured in Bravo 1.

(Right) Lobster being V-notched on St Aidan.


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Fig 3 │ Broad-scale habitat map displaying the hard/ soft grounds within NIFCA’s district, with the locations of the lobster

releases. ArcGIS data provided by Natural England (Dec 2016 release) and Latitude and longitude co-ordinates recorded on

St. Aidan and Bravo 1.

Map of sectors within NIFCA district

Legend

Hard Substrate (Rock) Soft sediments Lobster Release tracks < 150 100 – 150 50 - 100

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Fig 4 ǀ The distribution of v-notched lobsters (brought and released through wholesalers) by the Authority throughout the five sectors since 2000 to present day. 2,368

2,416 2,295

2,020

2,727

2,295

2,020

2,295

2,727 2, 295 2,416 2,368

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

1 2 3 4 5

Lob

ster

s V

-No

tch

ed

NIFCA Sectors

Distribution of V-notched Lobsters throughout NIFCA's 5 Sectors (2000- 2017)

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017


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2.3 Scheme Finance

The authority sets aside £10,500 each year in its annual budget for the scheme. This year

the total amount paid attributed for the purchasing of 1,012 lobsters was £10,428.50. The

total spent in purchasing lobsters from wholesalers has gradually increased since the

scheme began; the lowest in 2000, £5,003. However, in the early years donations and grants

helped with purchase of lobsters and the average price per kilo has also gradually increased

from its lowest recorded, £8.50 (2002) to a record high this year of £14 (Fig 5).

Fig 5 ǀ Graph showing the total cost spent on purchasing lobsters from wholesalers (and vessels in 2015) each

year, 2000 – 2017.

2.3.1 Donations

Since 2006 NIFCA has also received monetary donations from the fishing industry and its

committee members. To date the Authority has generously received an additional £22, 361

towards the scheme. We would like to thank everyone who has generously donated to the

scheme making it a success. Although no donations were received this year the local

industry has continued to be very supportive of the V-notching scheme. Pliers supplied to

the fishermen in 2015 have enable them to actively participate and V-notch lobsters at

liberty at sea. This has been reported (from NIFCO patrols) as a very popular practise

amongst fishermen.

£0

£2

£4

£6

£8

£10

£12

£14

£16

£0

£2,000

£4,000

£6,000

£8,000

£10,000

£12,000

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017A

v C

ost

per

Kilo

Tota

l Co

st o

f Lo

bst

ers

Cost of purchasing lobsters for V- Notching Scheme (2000- 2017)

Total Cost Av £ per Kilo


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2.3.2 Purchase of Lobsters

Lobsters purchased this year came solely from wholesalers. Previous efforts (in 2015) to

purchase berried hen lobsters directly from fishermen at sea proved unfeasible in achieving

the scheme’s target of V-notching 1,000 berried lobsters. Although this method was

advantageous for returning berried hens more efficiently and reducing the impacts of stress,

the numbers of berried hens available to purchase in an ad hoc manner from fisherman was

extremely low; approximately between 5 to 15 lobsters per vessel.

Prices varied throughout the season from £12 to £15 per kilogram (Table 2), with the

average price per kilo throughout the scheme £14; the highest in the schemes history. The

number of lobsters obtained at each purchase was at the request of NIFCA (in addition to all

being berried hens) to target the releases in specific sectors. This was done to increase the

overall number of releases in sectors which had in previous years not received as many

releases, in particular our most northern sector five (Fig 4).

Table 2 ǀ Purchase details of lobsters brought from wholesalers.

Date Supplier Weight (kg) No. of

Lobsters £ per Kilo

Invoice Total

20/07/2017 Blyth Fish Ltd 42.5 61 £13 £552.50

01/08/2017 Blyth Fish Ltd 87 148 £12 £1,044.00

17/08/2017 D.R. Collin and Son Ltd 407.3 497 £15 £6,110.00

31/08/2017 Moirs (North Shields) 91.9 162 £15 £1,378.50

08/09/2017 Blyth Fish Ltd 96 144 £14 £1,344.00

Total £10,429.00

4. Monitoring of scheme

Re-capture records of ‘V’-notched lobsters help to provide feedback on the scheme’s

success and insight for NIFCA to monitor V-notch population levels (Skerritt 2014).

Fishermen help provide this data in their monthly shellfish returns, in addition to eIFCO’s

collecting data from stock assessment surveys. Caution must be applied when viewing these

results, as these numbers do not represent individual lobsters, as a re-captured lobster can

be caught multiple times.

3.1 Shellfish Permit Returns

A condition of the shellfish permit is for all permit holders to submit monthly shellfish

returns to the Authority. Amongst other information collected, data on fishing effort

(average number of pots fished per month and number of days at sea) and number of V-

notched lobsters caught (and released) is gathered. Analysis of this data can provide an

insight of the spatial distribution of V-notched lobsters throughout the NIFCA district.


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Records show that the highest number of V-notched lobsters caught by fishermen was

within Sector Three (Amble to Embleton), with 3731 incidences and the least recorded

within Sector One the least (Tyne to Wansbeck) with 514 (Fig 6). Just looking at these figures

alone does not present an accurate overview across the district. Fishing effort must be

considered to standardise the data, as this varies considerably across our district as shown

by the yellow line in Fig 6. When this is applied to the data, it shows that sectors three and

four recorded the highest incidences of V-notch re-captures and two and five the least (Fig

7). As sector five has previously received fewer releases than the other sectors, it is not

surprising that fishermen record low numbers of V-notched lobster caught in this area,

however, sector two has the highest number of releases within the district, but is shown to

have one of the lowest recorded re-captures rates. It is possible that these V-notched

lobsters are migrating into different sectors once on the seabed. Experimental research into

the movement of caught and released European Lobsters have found that V-notched

lobsters tend to migrate further distances. This behaviour is not considered normal, but due

to possible disorientation of their new surroundings and/or homing behaviour (Skerritt

2014). With these uncertainties it is important that the scheme continues to purchase

lobsters from wholesalers across our district and releasing them in nearby sectors.

Another factor is the area of suitable hard habitat available. Within sector two the seabed

habitat is a higher mixture of soft sediments and rocky reef, whereas sectors three and four

present a higher coverage of rocky reef, providing increased opportunities for shelter (Fig 3).

Moreover, this information provides confirmation of individual’s survivability after their

release and their continual presence within the population all year round (Fig 8), showing

that a high number of V-notched lobsters are not migrating out of the district remaining

within local stocks.

Fig 6 │ Data taken from in monthly shellfish permit returns. Blue bars represent number of V-notched lobsters recorded by

fishermen and the yellow line represents fishing effort (average number of pots hauled x number of days fished) across

NIFCA’s five sectors.

0

50000000

100000000

150000000

200000000

0

500

1000

1500

2000

2500

3000

3500

4000

1 2 3 4 5

Number of recorded V-notched lobsters plotted against fishing effort

V-Notched Effort

V-n

otc

hed

rec

ord

ed Fish

ing u

nit effo

rt

NIFCA Sectors


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Fig 7 │ Graph showing the standardised re-capture rates of V-notched lobsters across the NIFCA five sectors.

Fig 8 │Standardised re-capture rates of V-notched lobsters across the NIFCA five sectors during 2016.

0

0.000005

0.00001

0.000015

0.00002

0.000025

0.00003

0.000035

0.00004

0.000045

1 2 3 4 5

Recorded Re-Capture of V-notches standarised with fishing effort

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Recorded Re-captures in each of the five sectors throughout 2016

1 2 3 4 5

Months

NIFCA Sectors

Rec

ord

s p

er f

ish

ing

un

it e

ffo

rt

Rec

ord

s p

er f

ish

ing

un

it e

ffo

rt


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3.2 2014- 16 Stock Assessment

Between March 2014 and March 2016 NIFCA, with the help of local fishermen carried out a

Stock Assessment project across the Northumberland district. This involved an

environmental IFCO going to sea aboard participating fishing vessels once a month,

recording and measuring every individual lobster hauled from their pots. The project re-

started again in October 2017.

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. The rates of V-notching are

highest off Seahouses (7.53%) and Holy Island (6.39%). 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.

Table 3. Summary of data showing the percentage of V-notched lobsters in stock assessment.

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

Photos taken while on Stock Assessment survey on board fishing vessels


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4. Future of V-notching scheme

As of the 1st October 2017, new National legislation1 implemented by Defra prohibits the

fishing for and landing of berried hens of European lobsters (and crawfish) within all English

waters. This legislation presents a consistent approach across all IFCAs, as previously six of

the ten IFCAs had already a ‘berried hen’ ban within their district implemented through

their byelaws. This new management has the same objective as the V-notching scheme, to

protect the breeding female population to safeguard continuous recruitment into the

fishery, thus helping to ensure its sustainability. As the V-notching scheme prioritises egg

bearing females, this new legislation supersedes any benefits of protection provided

through the scheme. It is therefore uncertain if the V-notching scheme will continue. The

Authority is considering options for either how to adapt the scheme or fund new

conservation programmes which benefit the local fishing industry.

Acknowledgements

The Authority is extremely grateful for everyone involved in this project and

would like to express our sincere thanks. Without the support and

participation from the local industry the v-notching scheme would not have

been possible or a continued success.

1 SI No.889. The Lobster and Crawfish (Prohibition of Fishing and Landing) (Amendment) (England) Order 2017

14

5. Appendix

Annex 1. showing all the size frequency distribution of female lobsters v-notched in 2017.

0

20

40

60

80

100

120

Fre

qu

ew

ncy

Carapace Length

CARAPACE LENGTH DISTRIBUTION LENGTHS OF V -NOTCHED LOBSTERS

Berried Non-Berried


15

Annex 2. Lobster V-notch Recording Sheet. Showing total egg development stage and carapace

length of all lobsters v-notched by NIFCA in 2017

Egg Development

Lobster CL (mm) Black/Green Eyed/Hatched Non-berried Total

87 28 2 8 38

88 31 0 4 35

89 23 0 7 30

90 54 2 15 71

91 35 4 3 42

92 83 2 7 92

93 58 1 7 66

94 43 5 7 55

95 48 4 6 58

96 40 5 3 48

97 37 3 2 42

98 43 3 1 47

99 20 1 4 25

100 44 3 0 47

101 32 1 1 34

102 50 2 1 53

103 16 0 1 17

104 21 1 1 23

105 12 1 0 13

106 17 1 0 18

107 13 1 0 14

108 12 2 2 16

109 10 1 1 12

110 8 3 0 11

111 11 1 3 15

112 6 0 1 7

113 3 0 2 5

114 2 1 2 5

115 6 0 1 7

116 3 0 1 4

117 1 0 0 1

118 1 0 0 1

119 3 0 0 3

120 8 0 2 10

121 3 1 0 4

122 6 0 0 6

123 1 0 1 2

124 3 0 0 3

125+ 22 3 7 32

TOTAL 857 54 101 1012


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6. 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

Skerritt D. (2014) ‘Abundance, Interaction and movement in a European Lobster Stock’ PhD.

Newcastle University, School of Marine Science and Technology.

SundelÖf A, Grimm V, Ulmestrand M, Fiksen Ø. (2015) ‘Modelling harvesting strategies for the

lobster fishery in northern Europe: the importance of protecting egg-bearing females’ The Society of

Population Ecology, 57:237- 251

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/

http://www.nifca.gov.uk/downloads/

http://www.nationallobsterhatchery.co.uk/whats-it-all-about/education/lobster-biology/

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