
Funded
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- Objectives
- Extensively sample the catch of vessel wells in port to obtain data for simulation studies.
Through simulation, explore improved port-sampling protocols for the fleet-level Best Scientific Estimate (BSE) of tropical tuna catch composition and its variance - Background
- Through its regular port-sampling program, the IATTC has been sampling the length distribution of yellowfin (YFT) and skipjack (SKJ) tunas caught in the Eastern Pacific Ocean tuna purse-seine fishery since 1954, Pacific bluefin tuna since 1973, and bigeye tuna (BET) since 1975. In 2000, this length-frequency sampling program was broadened to include collection of independent samples of the species composition of the catches. The sampling protocol implemented was based in part on the results of simulation studies conducted in the early 1990s using data collected in the late 1980s from 6 wells with dolphin-associated (DEL) and unassociated (NOA) tuna catches.
However, the performance of the protocol for the present-day fishery has not been fully evaluated, largely due to a lack of appropriate data. In particular, the fishery on floating objects (OBJ) has expanded considerably, yet the performance of the current sampling protocol for that fleet component has not been adequately studied. - Relevance for management
- In conjunction with work done during the IVT pilot study (Project B.3.a) and data generated by the Enhanced Monitoring Program (EMP), will generate data with which to explore options for improvements to the regular port-sampling designs for the BSE of catch composition for all purse-seine fleet components.
Improved sampling designs for fleet-level catch composition will result in greater precision of the catch composition estimates, among other things, which would be beneficial for stock assessments.
Results will likely benefit sampling programs of other tuna Regional Fisheries Management Organizations - Duration
- January – December 2024
- Workplan and status
- January – October 2024: collect high-frequency well sampling data in ports of Mexico and Ecuador, focusing on 1-single set OBJ wells, NOA wells and DEL wells.
- September – December 2004: conduct a simulation study to evaluate potential improvements to fleet-level sampling designs.
- November 2024: Conduct an external review of potential sampling design improvements.
- External collaborators
- National observer programs
Purse-seine fleet
Funding for sampling in Mexico and Ecuador provided by the United States
- Deliverables
- Reports for the SAC and the Commission; publications in peer-reviewed journals.
- Updated date: 01 Mar 2024
- Progress summary for the reporting period
- Since January, a 3-person team has been sampling in the port of Manta, Ecuador. To date they have sampled 10 wells of 8 trips, 7 with catch from NOA sets, 2 with catch from DEL sets and with catch from a single OBJ set. Also, a training workshop was held at the start of March in Mazatlan, Mexico, to prepare the 2-sampler team, which will begin sampling in that port this month.