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# STT/STJ Yellowtail Fishing Trips

Population Size, Growth, Mortality and Movement Patterns of Yellowtail Snapper ( Ocyurus chrysurus ) in the U.S. Virgin Islands CRP Funded Project NMF4540114 Funding : Federal=$132,850 CFMC=$20,000 STFA in-kind=$11,200. # STT/STJ Yellowtail Fishing Trips. Yellowtail lbs /Trip.

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# STT/STJ Yellowtail Fishing Trips

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  1. Population Size, Growth, Mortality and Movement Patterns of Yellowtail Snapper (Ocyuruschrysurus) in the U.S. Virgin Islands CRP Funded Project NMF4540114Funding :Federal=$132,850CFMC=$20,000STFA in-kind=$11,200

  2. # STT/STJ Yellowtail Fishing Trips

  3. Yellowtail lbs/Trip

  4. Yellowtail Snapper Annual STT/STJ Landings# lbs

  5. Annual Yellowtail Landings # Fish

  6. Average Monthly Handline & SeineTrips(1997-2008 Average)

  7. Yellowtail per Trap /Haul

  8. Pit Tags

  9. Scanner for Port Sampling

  10. Weight Calculations

  11. Study Status

  12. Port Sample Locations

  13. Calculation of Total Mortality Rate (Z) Where: is the number of fish at time (t) and Z is the rate of total mortality. An age specific instantaneous rate of Z was calculated by solving the Von Bertalanffy growth equations for t (median age of the size class in the frequency distribution.* Where: is the length (in mm) at age (t).is the asymptotic length at which growth is zero. t0is included to adjust the equation for the initial size of the organism and is defined as age at which the organisms would have had zero size. Solving equation for t (age) allows for calculation of the age (in years) of each size class. 2005=0.174 2011-12=0.249 *Manooch, C.S. III. and C.L. Drennon, 1987. Age and growth of yellowtail snapper and queen triggerfish collected from the U.S. Virgin Islands and Puerto Rico. Fish. Res. 6:53-68. Otolith analysis.

  14. Hand line Size Frequency

  15. Fish Trap Size Frequency

  16. Tagging/Port Sampling Summary

  17. Summary of Mortality • 2005 Size/Frequency Distribution=0.174 (0.0154/month) • 2011-12 Size/Frequency Distribution=0.249 (0.0208/Month) • Coral World • Initial “Fishing/Transport” Mortality=9.6%Heavy stress from transport to tanks analogous to additional mortality from predators. • Tag Loss= 1.6% • Pre “Catastrophic” Mortality=2.1% (matches 2011-2012 rate)

  18. Gear Selectivity Where: S is Selectivity and and are calculated iteratively via nonlinear regression. From the non-linear model (Proc NLIN in SAS) with known values of size class and percent of the sampled population for that size class. The output was estimates of both parameters, which were then used within the selectivity equation to estimate size selectivity for each size class and particularly the size class at which selectivity peaked.

  19. Selectivity Analysis: Fish Traps

  20. Selectivity Analysis: Hand Line

  21. Coral World Studies • Assess rate of tag loss (1.7%) • Assess mortality • 9.6% initial “fishing/transport” mortality • Mortality following initial mortality almost exactly that indicated from size/frequency analysis. • Catastrophic mortality after 3 weeks. • Necropsy revealed that 60% had small livers when compared to fish from market and 69% had liver fluke infestation.

  22. Survivorship at Coral World

  23. Recaptures • None so far • Comparison with Rick Niemeth’s tagging. All tagging done on aggregation site. To date Niemeth has tagged • 751 Nassau (2004-2010) and have recaptured 187 back on the aggregation site. In addition 3 have been captured by fishermen and reported to UVI by STFA members (0.5/year). • 661 yellowfin grouper and recaptured 25. All tags and recaps were on the aggregation site. • 3644 red hind (1999-2006) and recaptured 99. 47 Red hind were recaptured off the aggregation site (6.7/year).

  24. Next Steps • Finish Coral World Studies • Double Tagging with Floy and Pit tags. Started 8/15) • Floy Tagging of remainder • Continue Port Sampling. • Data from DFW.

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