1. Black Sea Bass – Northern Stock Coastal-Pelagic/ASMFC Working Group Review June 15, 2010

2. Update of assessment approach adopted by the Data Poor Stocks Working Group ( Dec 2008) and the 2009 assessment (June 2009). Approach: Length-based model of population parameters - require time series of catch, survey indices Compare results to biological reference points to determine stock status Produce projections based on model results

3. Life History – Distributed Maine through Gulf of Mexico Managed as single stock north of Cape Hatteras Protogynous hermaphrodite: Transition to male at age 2-5 Seasonal migrations inshore/offshore Maximum age 15 (?) 50% mature 21 cm

4. Black sea bass size at maturity from NEFSC spring surveys

7. 2008 and 2009 commercial black sea bass landings

8. Values in blue - estimates from commercial ratio

9. Recreational Discard weight Discard weight estimated using landing mean weight

10. OT from observer 1989-2008 Pot and handline from VTR 1994-2008 2009 estimate from series average

11. Black sea bass catch estimates Rec discard mortality = 25% Com discard mortality = 25-50%

12. 2005-2009 average sea bass catch components

13. Combined Recreational/Commercial landings length frequency 1985 1990 1995 2000

14. Combined Recreational/Commercial landings length frequency 2001 2002 2003 2004

15. Combined Recreational/Commercial landings length frequency 2005 2006 2007 2008

17. Mean and Median length of sea bass landings median mean

18. Northeast Fisheries Science Center Trawl Survey Spring offshore strata 1968 – 2009 (Bigelow conversion coefficient = 3.416) Winter offshore strata 1992 – 2007 Log e transform indices

19. NEFSC Indices of sea bass adult abundance (>22 cm) (stratified mean #/tow)

20. NEFSC Spring and Winter indices of juvenile abundance (stratified mean #/tow)

21. SCALE model

22. SCALE model (P. Nitschke NMFS,NEFSC) Length based catch at age model Inputs : NEFSC spring (1968-2009) and winter surveys (1992-2007) adult (> 22 cm) and recruitment (< 14 cm) Survey length frequencies (1968-2009,1992-2007) Fishery catch series (1968-2009) Fishery length frequencies (1984-2009) Selectivity periods (1984-1997, 1998-2000, 2001-2009) Mean length at age and std. deviations Length-weight equation (from survey series) Natural mortality estimate (0.4)

23. Sea Bass growth used in SCALE Mean length + 2 stdev

24. Selectivity used in the SCALE model

25. Model results influenced by presence of juvenile indices, weighting factors, etc. Which is correct model? Adopted model averaging approach (Burnham and Anderson (2002)

26. Scale modeling approach:

27. Observed and estimated average (+ 2 std dev) black sea bass catch

28. NMFS Spring index – predicted vs observed (index +1)

29. NMFS Winter index – predicted vs observed (index +1)

30. Wt’d Average Fishing mortality + 2 std dev from SCALE model estimates Fmsy

31. Wt’d Average Recruitment + 2 std dev from SCALE model estimates

32. Wt’d Average Total Biomass + 2 std dev from SCALE model estimates Bmsy

33. Wt’d Average Total Abundance + 2 std dev from SCALE model estimates

34. Wt’d Average Spawning Stock Biomass + 95% CI from SCALE model estimates

35. Relationship between SSB and F

36. Projection approach Use predicted output as new input. Input F for projections and allow model to predict catch. Survey data in 2009 and 2010 treated as missing. 2010 Catch assumed equal to quota plus average discard. 2010-2012 lf 5 year average Average spring and winter indices Average recruitment variation, starting recruitment and starting F

37. Projection if F2010 = F2008

38. Retrospective patterns in typical model run

39. Comparison to previous assessments

40. NEFSC Spring offshore survey- 2004

41. NEFSC Spring offshore survey- 2005

42. NEFSC Spring offshore survey- 2006

43. NEFSC Spring offshore survey- 2007

44. NEFSC Spring offshore survey- 2008

45. NEFSC Spring offshore survey - 2009