- Objectives
- Update the assessments of bigeye, yellowfin, and skipjack tunas
- Background
- Assessments of bigeye, yellowfin, and skipjack are conducted every year
- Bigeye and yellowfin assessments use the Stock Synthesis modeling platform
- Skipjack assessment is based on stock status indicators
- Assessments are updated annually, using the most recent data
- Major improvements to the assessments (methods and assumptions) are implemented periodically
- Relevance for management
- The staff’s management advice for tunas is based on its stock assessments
- The duration of the seasonal closures recommended by the staff for bigeye and yellowfin are based on the F multipliers estimated in the assessments
- Duration
- Every year (March-May)
- Workplan and status
- 15 March: data for previous year available; assessments initiated
- Three weeks before SAC meeting: Assessment reports posted on IATTC website
- Mid-May: Present assessments at SAC meeting
- Deliverables
- Stock assessment reports for the SAC and the IATTC; presentations at SAC and IATTC meetings
- Updated date: 01 Apr 2021
- Progress summary for the reporting period
- Benchmark assessment conducted for bigeye 2020
- Benchmark assessment conducted for yellowfin 2020
- Indicators constructed for the three species 2021
- Challenges and key lessons learnt
- The results of the bigeye and yellowfin assessments were considered unreliable, and they were improved for the 2020 benchmark assessments (Projects H.1.a and H.1.b).
- There is uncertainty about the stock structure of yellowfin tuna
- The risk analysis for bigeye tuna shows a bimodal pattern
- SAC-11-05 Bigeye, yellowfin, and skipjack tuna: indicators of stock status
- SAC-11-06 Bigeye tuna: benchmark assessment
- SAC-11-07 Yellowfin tuna: benchmark assessment
- SAC-12-06 Assessment methods for skipjack in the EPO: a proposal relying on recent data from the IATTC regional tuna tagging program (2019-2022)
- SAC-12-05 Stock status indicators (SSIs) for tropical tunas in the eastern Pacific Ocean