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METHODS WORKING GROUP March 19 to 23, 2007

This report covers methods for estimating missing catch data, developing CPUE standardization practices, and providing capacity information to the Commission. It discusses testing methods, CPUE standardization methodologies, and conclusions on overcapacity in fisheries.

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METHODS WORKING GROUP March 19 to 23, 2007

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  1. METHODS WORKING GROUP March 19 to 23, 2007 SCI-028 EXECUTIVE SUMMARY SCI-032 DETAILED REPORT

  2. Objectives • Estimation of missing catch data • Development of CPUE Standardization practices • Provision of capacity information to the Commission

  3. 1. Estimation of missing catch data How to extrapolate catches back in time when catch reports only start after the fishery has already been operating and capturing a species for some time

  4. missing catch • Testing: • Split known data series into 2 parts • Estimate parameters with one part and predict data with the other part • Compare known vs predicted data

  5. missing catch • Result: Methods that assume that species catch ratios for a fishery change linearly through time performed well

  6. 2. Development of CPUE Standardization practices Standardization methodologies are diverse. Difficult to adequately compare and integrate the available CPUE series. Develop a comprehensive manual that can serve as reference tool for CPUE standardization.

  7. Outline(SCI-032, Appendix 4) 1. Standardization of CPUE theory 2. Data Input, Preparation and Evaluation, 3. Methods available for standardization of catch and effort data 4. Diagnostics 5. Index of Abundance Estimation 6. Software and algorithms available for standardization of CPUE 7. Other Topics related to relative index of abundance estimation

  8. Actions Ad hoc team of scientists will write the manual (volunteers needed) Led by SC-STATS Chair, Dr. M. Ortiz Target completion ± 1 year Please comment on the OUTLINE

  9. 3. Capacity information to the Commission Rec. [06-19] established a WG on Capacity and asked the SCRS: • A: Information on short- and long-term stock conditions and harvest levels in ICCAT fisheries for the most recent year(s) available (2006 SCRS Report) • B: Data on effort and CPUE by flag, gear, season and area (Methods WG)

  10. A: Information on short- and long-term stock conditions

  11. Data Sources • Vessel Record > 24 m • Informal list of vessels 15-24 m • Task I Fleet Characteristics • Task II catch-effort • Tropical purse seine carrying capacity • BFT Farming capacity • From stock assessments

  12. WG Methods Conclusions • More than 3,400 large scale vessels • GRT > 860,000 t • Carrying capacity LL+PS+BB = 561,000 t • 6,600 vessels in the 15-24 m range • Total Carrying Capacity likely to substantially exceed the recent level of catches

  13. WG Methods Conclusions • Information relating catch by flag and gear to fishing effort is sparse • Very complete information is available to National Scientists for some fleets • Tropical purse seine fleet in 2005: • 39 vessels • Carrying capacity of 50,000 t • Caught 175,000 t

  14. WG Methods Conclusions: BFT-E • Farming capacity is about 56,000t (45,000t round weight of fish at time of capture). • Fishing capacity exists to fully supply the farms

  15. WG Methods Conclusions • A simple estimate of overcapacity: • F/FMSY > 1.0 • Stock F/FMSY • YFT 1.1 • ALB-N 1.5 • BFT-W 1.7 • BFT-E 3.1 • SWO-M 1.3 • BUM >1.0 • WHM >1.0

  16. EPILOGUE Commission’s WG on Capacity met (July, Raleigh, USA) and examined the results, and concluded:

  17. Differences between • Latent vs Active Capacity • Overcapacity evident for BFT-E • 2007 SCRS should refine these estimates • SCRS should report on each stock • Current status • Information on the different fleets actively engaged in the fisheries

  18. What Next? • Another MethWG Inter-sessional in 2008? • An ad-hoc Capacity Meeting in 2008? • Wait for the Commission’s decision?

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