Stock Assessment for Central Southern Management Area (CSMA) Striped Bass Stocks

1. Stock Assessment for Central Southern Management Area (CSMA) Striped Bass Stocks Marine Fisheries Commission Business Meeting February 11, 2011

2. Overview • Available Data • Methods • Results • Conclusions • Research Recommendations

3. Assessment Review • Internal Review • External Peer Review

4. Available Data • Fishery-independent • NCWRC Spawning Grounds Surveys • Catch rates • Scales (Tar River) • NCDMF Program 915 • Catch rates

5. Available Data • Fishery-dependent • Trip ticket program (landings) • Creel survey • Biological samples not used (too few samples)

6. Data Limitations • The input data limitations for these analyses are twofold: • Limitations inherent in the surveys collecting the data • Examples: Lack of defined spawning areas, use of multispecies survey • Analytical limitations resulting from data that are not complete or that were not collected • Examples: Incomplete age data by system, lack of system specific life history parameters

7. Methods • Despite data limitations, multiple methods were applied to attempt to determine stock status • Trend analysis • Catch curves • Ultimately, none of the methods were able to determine stock status reliably

8. Trend Analysis • Catch-per-unit-effort (CPUE) • NCWRC Spawning Grounds Survey: number of striped bass collected per hour of sampling effort • NCDMF Program 915: number of striped bass collected per 160 sets in a year (12 hr net set of 240 yds) • Examined CPUE by age (cohort) over time

9. CPUE Ages 3 to 6 Neuse River-Spawning Grounds, 1994-2009 CPUE = number of fish per electrofishing hr

10. CPUE Ages 3 to 6 Neuse River-Program 915, 2003-2009 CPUE = number of fish in 160 gill net sets

11. CPUE Ages 3 to 7Tar/Pamlico River-Spawning Grounds, 1996-2009 CPUE = number of fish per electrofishing hr

12. CPUE Ages 3 to 7 Tar/Pamlico River-Program 915, 2003-2009 CPUE = number of fish in 160 gill net sets

13. Catch Curves • Used to estimate mortality from catch or survey age data • Total mortality (Z) is the sum of fishing (F) and natural (M) mortality Z = F + M

14. Catch Curves

15. Annual Total Mortality (Z) Neuse River-Spawning Grounds

16. Annual Total Mortality (Z) Neuse River-Program 915

17. Annual Total Mortality (Z) Tar/Pamlico River-Spawning Grounds

18. Annual Total Mortality (Z) Tar/Pamlico River-Program 915

19. Size Distribution • Changes in length and age distribution can be indicative of stock trends • Expanding distribution  rebuilding • Truncated distribution  declining

20. Neuse River Commercial Length Frequency

21. Neuse River Spawning Grounds Survey Length Frequency

22. Neuse River Program 915 Length Frequency

23. Pamlico River Commercial Length Frequency

24. Tar/Pamlico River Spawning Grounds Survey Length Frequency

25. Pamlico River Program 915 Length Frequency

26. Conclusions • Total mortality (Z) estimates vary without trend providing little information for stock status determination • Length distributions provide no substantial evidence of a viable stock • The size and age distributions, low abundance, and the absence of older fish support continued management efforts to promote enhancement of the striped bass fisheries in each system

27. Research Recommendations • Since the 2004 FMP, significant efforts were made to fill CSMA data gaps, but critical data are still needed • Life history parameters • Additional fishery-dependent data • Improved fishery-independent data • Above data necessary to perform a reliable, quantitative assessment • Funding and staff needed to collect needed data