1 / 67

ASSESSMENT OF BIGEYE TUNA ( THUNNUS OBESUS ) IN THE EASTERN PACIFIC OCEAN

ASSESSMENT OF BIGEYE TUNA ( THUNNUS OBESUS ) IN THE EASTERN PACIFIC OCEAN. January 1975 – December 2005. Overview of assessment. Age-structured, statistical, catch-at-length model (A-SCALA). Quarterly time step from 1975 to the start of 2005.

astro
Download Presentation

ASSESSMENT OF BIGEYE TUNA ( THUNNUS OBESUS ) IN THE EASTERN PACIFIC OCEAN

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. ASSESSMENT OF BIGEYE TUNA (THUNNUS OBESUS) IN THE EASTERN PACIFIC OCEAN January 1975 – December 2005

  2. Overview of assessment • Age-structured, statistical, catch-at-length model (A-SCALA). • Quarterly time step from 1975 to the start of 2005. • No net movement of fish between the eastern and western Pacific.

  3. Major changes • No major model changes except new and updated catch, effort, and length-frequency data.

  4. Sensitivity analyses • Spawner-recruitment relationship (steepness = 0.75) • Assumed value for the asymptotic length parameter of the Richards growth curve • Inclusion of the Chinese Taipei longline length-frequcy data • Relationship between recruitment an the el Nino index

  5. 8 5, 13 9 3, 11 4, 12 1, 6-7 2, 10 Bigeye fishery definitions Recent FLT (2-5) Discards (10-13) N Longline (8) S Longline (9) Early FLT (1) Early & Recent UNA (6, 7)

  6. S LL N Offshore FLT Early UNA Recent UNA N LL Early FLT S Offshore FLT Equatorial FLT Coastal FLT Catch

  7. Effort S LL Recent UNA N LL N Offshore FLT Early UNA Equatorial FLT Coastal FLT Early FLT S Offshore FLT

  8. S LL N Offshore FLT Early UNA Recent UNA N LL Early FLT S Offshore FLT Equatorial FLT Coastal FLT CPUE

  9. Recent UNA N LL S LL Coastal FLT N Offshore FLT Early UNA Early FLT S Offshore FLT Equatorial FLT Length frequency data

  10. Discards Northern FLT Inshore FLT Southern FLT Equatorial FLT

  11. Results • Fit to the length frequency • Growth • Fishing mortality • Selectivity • Recruitment • Biomass • Catchability

  12. Recent UNA N LL S LL Coastal FLT N Offshore FLT Early UNA Early FLT S Offshore FLT Equatorial FLT Average fit to the length frequency data

  13. Fit to recent length frequency data

  14. Fit to recent length frequency data

  15. Growth

  16. Fishing mortality 1-4 5-8 13-16 9-12 21-24 17-20 29-32 25-28 37-40 33-36

  17. Age-specific fishing mortality

  18. Selectivity Recent UNA N LL Early UNA S LL Coastal FLT N Offshore FLT Early FLT S Offshore FLT Equatorial FLT

  19. Catchability N Offshore FLT Equatorial FLT Coastal FLT Early FLT S Offshore FLT

  20. S LL N LL Recent UNA Early UNA Catchability

  21. Northern FLT Inshore FLT Equatorial FLT Southern FLT Catchability

  22. Recruitment

  23. Biomass

  24. Spawning biomass

  25. No-fishing plot

  26. Average weight Combined Surface Combined LL Early UNA Recent UNA N LL S LL Early FLT Coastal FLT N Offshore FLT Galapagos FLT S Offshore FLT

  27. Biomass

  28. Recruitment

  29. Comparisons to reference points • Spawning biomass depletion • Yield curve

  30. Spawning biomass ratio

  31. SBR comparison with last year

  32. Time varying indicators

  33. Yield curve

  34. AMSY-quantities

  35. AMSY-quantities -- assumed F

  36. AMSY-quantities – by fishery

  37. Forward simulations • Spawning biomass depletion • Biomass • Surface fishery catch • Longline catch

  38. Spawning biomass ratio

  39. Biomass

  40. Predicted catches

  41. Stock-recruitment relationship (h = 0.75)

  42. Biomass

  43. Recruitment

  44. Spawning biomass ratio

  45. Spawner-recruitment curve

  46. Yield curve

  47. Assumed value for the asymptotic length parameter of the Richards growth curve

  48. Growth curves

  49. Maximum length

  50. Likelihoods

More Related