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The Cod Day - Science

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

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The Cod Day - Science

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

  2. Outline • North Sea cod • West of Scotland cod • Future developments

  3. North Sea cod – Outline • Data • Stock area • Catch data • Survey data • Stock distribution • Value estimates • Sampling and observer coverage • Biological data • Assessment • Advice

  4. North Sea cod – stock area

  5. North Sea cod – official landings

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

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

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

  9. North Sea cod – Int. cod catch

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

  11. 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

  12. North Sea cod – surveys 2009 age 1 2012 age 1 2010 age 1 2011 age 1 2008 age 1 IBTS Q1 2009 age 2 2012 age 2 2010 age 2 2011 age 2 2008 age 2 2009 age 3+ 2012 age 3+ 2010 age 3+ 2011 age 3+ 2008 age 3+

  13. North Sea cod – surveys IBTS Q1

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

  15. North Sea cod – modelled abundance distribution

  16. North Sea cod – modelled abundance distribution

  17. North Sea cod – modelled abundance distribution

  18. North Sea cod – modelled abundance distribution

  19. North Sea cod – modelled abundance distribution

  20. North Sea cod – modelled abundance distribution

  21. North Sea cod – VMS-based landings distribution

  22. North Sea cod – VMS-based landings distribution

  23. North Sea cod – VMS-based landings distribution

  24. North Sea cod – VMS-based landings distribution

  25. North Sea cod – VMS-based landings distribution

  26. North Sea cod – observer coverage 2011

  27. North Sea cod – observer coverage 2011

  28. North Sea cod – observer coverage 2011

  29. North Sea cod – observer coverage 2011

  30. North Sea cod – port sampling coverage 2011

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

  32. North Sea cod – natural mortality estimates

  33. North Sea cod – maturity estimates

  34. 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

  35. North Sea cod – assessment

  36. North Sea cod – assessment Fmp

  37. North Sea cod – assessment

  38. North Sea cod – assessment Removals

  39. North Sea cod – assessment Removals multiplier

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

  41. 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.

  42. 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]

  43. 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.

  44. North Sea cod – forecasts & advice (June 2012) Table A: (note 2012 TAC = 31.8)

  45. North Sea cod – forecasts & advice (June 2012) Table B: (note 2012 TAC = 31.8)

  46. West of Scotland cod • See next file…

  47. North Sea cod – TR1 value maps

  48. North Sea cod – TR1 value maps

  49. North Sea cod – TR1 value maps

  50. North Sea cod – TR1 value maps

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