The Cod Day Marine Laboratory, Aberdeen, 2 October 2012 The Cod Day - Science Coby Needle, Nick Bailey, Rui Catarino, Steven Holmes Marine Laboratory Aberdeen

The Cod DayMarine Laboratory, Aberdeen, 2 October 2012

The Cod Day - Science

Coby Needle, Nick Bailey, Rui Catarino, Steven Holmes

Marine Laboratory

Aberdeen

Outline

• North Sea cod• West of Scotland cod• Future developments

North Sea cod – Outline

• Data– Stock area– Catch data– Survey data– Stock distribution– Value estimates– Sampling and observer coverage– Biological data

• Assessment• Advice

North Sea cod – stock area

North Sea cod – official landings

Belgium2%

Denmark18%

France2%

Germany8%

Netherlands7%

Norway18%

Sweden1%

Scotland36%

England & Wales8%

North Sea cod – Int. effort

TR1 = Trawl gear with mesh ≥ 100mm


TR2 = Trawl gear with mesh ≥ 70mm & < 100mm


GN = Gill nets & entangling nets

Reg. gear 2011

TR1 68.8%

TR2 11.6%

GN 10.8%

BT2 5.2%

BT1 1.6%

GT 1.3%

LL 0.7%

TR3 V small %

North Sea cod – Int. cod catch

North Sea cod – catches

2011 Removals = 67 ktLandings = 35 kt (52%), discards = 11.7 kt (17%), unaccounted = 20.3 kt

Unaccounted

Discards

Landings

North Sea cod – surveys

• Available surveys:– IBTS Q1 1983-2012– IBTS Q3 1991-2011– ScoGFS Q3 1982-2011– EngGFS Q3 1992-2011– North Sea Commission Fishers’ Survey

• Only IBTS Q1 used in assessment– Possible changes in catchability in Q3– Fishers’ Survey not quantitative


IBTS Q1

2008 age 1 2009 age 1 2010 age 1 2011 age 1 2012 age 1

2008 age 2 2009 age 2 2010 age 2 2011 age 2 2012 age 2

2008 age 3+ 2009 age 3+ 2010 age 3+ 2011 age 3+ 2012 age 3+


IBTS Q1


North SeaCommission

Fishers’Survey 2011

North Sea cod – modelled abundance distribution






North Sea cod – VMS-based landings distribution

4°E0°4°W8°W12°W

62°N

58°N

54°N

50°N

Cod LPUE 2007

Legend

kg year

0 - 5,000

5,001 - 15,000

15,001 - 30,000

30,001 - 45,000

45,001 - 75,000

75,001 - 125,000

125,001 - 270,000


4°E0°4°W8°W12°W

62°N

58°N

54°N

50°N

Cod LPUE 2008

Legend

kg year

0 - 5,000

5,001 - 15,000

15,001 - 30,000

30,001 - 45,000

45,001 - 75,000

75,001 - 125,000

125,001 - 270,000


4°E0°4°W8°W12°W

62°N

58°N

54°N

50°N

Cod LPUE 2009

Legend

kg year

0 - 5,000

5,001 - 15,000

15,001 - 30,000

30,001 - 45,000

45,001 - 75,000

75,001 - 125,000

125,001 - 270,000


4°E0°4°W8°W12°W

62°N

58°N

54°N

50°N

Cod LPUE 2010

Legend

kg year

0 - 5,000

5,001 - 15,000

15,001 - 30,000

30,001 - 45,000

45,001 - 75,000

75,001 - 125,000

125,001 - 270,000


4°E0°4°W8°W12°W

62°N

58°N

54°N

50°N

Cod LPUE 2011

Legend

kg year

0 - 5,000

5,001 - 15,000

15,001 - 30,000

30,001 - 45,000

45,001 - 75,000

75,001 - 125,000

125,001 - 270,000

North Sea cod – observer coverage 2011

Fleet Declared landings (tonnes)

Number of trips sampled

Discard weight (tonnes)

Discard rate

All 10505 39 3414 24.5%

TR1 (whitefish)

10228 28 2529 19.8%

TR2 (Nephrops)

222 11 885 79.9%




North Sea cod – port sampling coverage 2011

Fleet Declared landings (tonnes)

Number of trips

Number of trips sampled

Number of fish measured

Number of otoliths taken

All 10773 5180 39 10205 4546

North Sea cod – mean weight-at-age in catches

0

2

4

6

8

10

12

14

16

1960 1970 1980 1990 2000 2010

kg

Mean weights-at-age in stock/catch

Age 1

Age 2

Age 3

Age 4

Age 5

Age 6

Age 7

Age 8

Age 9

North Sea cod – natural mortality estimates

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

1958 1968 1978 1988 1998 2008 2018

Age 1

Age 2

Age 3

Age 4

Age 5

North Sea cod – maturity estimates

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5 6 7

Age

Pro

port

ion

mat

ure

North Sea cod – assessment

• Assessed using the SAM method– Includes IBTS Q1 survey, landings, discards– Landings and discards from 1993-2011 are

scaled by an estimated parameter– Indicates unaccounted removals

• SAM is a robust approach and is increasingly widely used at ICES– SAM: NS cod, western Baltic plaice, NS sole,

Kattegat cod, NS herring– TSA: Cod VIa, haddock VIa



Fmp



Removals


Removals multiplier

North Sea cod – forecasts & advice (June 2012)

• Reduce F in steps from 2008 onwards:– 2009 F = 75% 2008 F– 2010 F = 65% 2008 F– 2011 F = 55% 2008 F– And so on…

• Most recent estimate of 2008 F used at each step.

• Apply sliding-F rule:

Management plan has two phases:

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0 50 100 150 200

SSB at start of current year (000 tonnes)

Targ

et F

Blim Bpa

#1 used until suggested TAC is lower than that from #2,or F = 0.4 for three years


• For both management plan phases:– Maximum effort reduced in line with F (but with bycatch rules).– ± 20% constraint on annual quota changes.– Forecasts based on estimate total removals, which are then split

into:• Landings (quota).• Discards.• Unaccounted removals.

• Other Articles relevant also, e.g.:– Article 9: data-poor situations.– Article 10: different approach if recovery not working.– Article 13: derogations to reduce effort cuts.


• MSY:– F(msy)

• MSY framework:– F’ = F(msy) * SSB(2012) / B(pa)

• MSY transition rule:– More gradual shift to F(msy)

• Zero catch• Roll-over landings• [Mixed-fisheries advice]


• Two versions of advice depending on intermediate year (2012) assumptions:– Table A: management plan followed in 2012,

giving 18% reduction in F.– Table B: recent trend in F continues, giving

12% reduction in F.

• ICES recommends Table B.


Rationale Basis Ftotal 2013

Landings 2013

Discards 2013

Unalloc 2013

SSB 2014

dSSB dTAC

Management plan

TAC cons.

0.26 25.4 6.5 8.6 107 +37%

-20%

Table A: (note 2012 TAC = 31.8)


Rationale Basis Ftotal 2013

Landings 2013

Discards 2013

Unalloc 2013

SSB 2014

dSSB dTAC

Management plan

TAC cons.

0.27 25.4 6.6 8.6 103 +36%

-20%

MSY F msy

0.19 19 4.9 6.4 112 +47%

-41%

MSY framework

F’ 0.10 10 2.5 3.4 123 +63%

-69%

MSY transition

Rule 0.29 28 7.2 9.4 101 +33%

-13%

Zero catch F = 0 0.00 0 0.0 0.0 136 +80%

-100%

Rollover landings

Landings 2012

0.49 43 11.5 14.6 82 +8% +34%

Table B: (note 2012 TAC = 31.8)

West of Scotland cod

• See next file…

North Sea cod – TR1 value maps








Future developments – CCTV estimates of discard rates

• Work progressing on discard-rate estimation

• Potentially a very important data source• Several current limitations:

– Resources (equipment and staff)– Methodology– Quality of data



• Work progressing on discard-rate estimation

• Potentially a very important data source• Several current limitations:

– Resources (equipment and staff)– Methodology– Quality of data

• Hope to maintain cameras at least for scientific observation

Future developments – draft management area proposals

North Sea, Skaggerak,Eastern ChannelRockall

IrishSea

Baltic

West ofScotland

North Sea, Skaggerak,Eastern ChannelRockall

IrishSea

Baltic

West ofScotland

Future developments – draft management area proposals

Northern NS and Shelf

Southern NS

Rockall

Wider Celtic Seas

IrishSea

Baltic

Documents

The Cod Day Marine Laboratory, Aberdeen, 2 October 2012 The Cod Day - Science Coby Needle, Nick Bailey, Rui Catarino, Steven Holmes Marine Laboratory Aberdeen