The Cod Day Marine 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

North Sea cod – Int. effort TR1 = Trawl gear with mesh ≥ 100mm

North Sea cod – Int. effort TR2 = Trawl gear with mesh ≥ 70mm & < 100mm

North Sea cod – Int. effort GN = Gill nets & entangling nets

Reg. gear2011 TR168.8% TR211.6% GN10.8% BT25.2% BT11.6% GT1.3% LL0.7% TR3V small % North Sea cod – Int. cod catch

North Sea cod – catches 2011 Removals = 67 kt Landings = 35 kt (52%), discards = 11.7 kt (17%), unaccounted = 20.3 kt Unaccounted Discards Landings

North Sea cod – surveys Available surveys: –IBTS Q –IBTS Q –ScoGFS Q –EngGFS Q –North Sea Commission Fishers’ Survey Only IBTS Q1 used in assessment –Possible changes in catchability in Q3 –Fishers’ Survey not quantitative

North Sea cod – surveys IBTS Q age age age age age age age age age age age age age age age 3+

North Sea cod – surveys IBTS Q1

North Sea cod – surveys North Sea Commission Fishers’ Survey 2011

North Sea cod – modelled abundance distribution

North Sea cod – VMS-based landings distribution

North Sea cod – observer coverage 2011 FleetDeclared landings (tonnes) Number of trips sampled Discard weight (tonnes) Discard rate All % TR1 (whitefish) % TR2 (Nephrops) %

North Sea cod – observer coverage 2011

North Sea cod – port sampling coverage 2011 FleetDeclared landings (tonnes) Number of trips Number of trips sampled Number of fish measured Number of otoliths taken All

North Sea cod – mean weight-at- age in catches Age 1 Age 2 Age 3 Age 4 Age 5 Age 6 Age 7 Age 8 Age 9

North Sea cod – natural mortality estimates

North Sea cod – maturity estimates

North Sea cod – assessment Assessed using the SAM method –Includes IBTS Q1 survey, landings, discards –Landings and discards from 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

North Sea cod – assessment

F mp

North Sea cod – assessment

Removals

North Sea cod – assessment 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: Blim Bpa #1 used until suggested TAC is lower than that from #2, or F = 0.4 for three years

North Sea cod – forecasts & advice (June 2012) 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.

North Sea cod – forecasts & advice (June 2012) 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]

North Sea cod – forecasts & advice (June 2012) 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.

North Sea cod – forecasts & advice (June 2012) RationaleBasisF total 2013 Landings 2013 Discards 2013 Unalloc 2013 SSB 2014 dSSBdTAC Management plan TAC cons %-20% Table A: (note 2012 TAC = 31.8)

North Sea cod – forecasts & advice (June 2012) RationaleBasisF total 2013 Landings 2013 Discards 2013 Unalloc 2013 SSB 2014 dSSBdTAC Management plan TAC cons %-20% MSYF msy %-41% MSY framework F’ %-69% MSY transition Rule %-13% Zero catchF = %-100% Rollover landings Landi ngs %+34% Table B: (note 2012 TAC = 31.8)

West of Scotland cod See next file…

North Sea cod – TR1 value maps

North Sea cod – TR2 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

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 Hope to maintain cameras at least for scientific observation

Future developments – draft management area proposals