Improve the yellowfin tuna stock assessment:Explore alternative hypotheses of stock structure and life-history for YFT in exploratory stock assessment models

Project H.1.b-2 - Improve the yellowfin tuna stock assessment:Explore alternative hypotheses of stock structure and life-history for YFT in exploratory stock assessment models

01 Jan 2021 - 31 Dec 2024

Program(s) in charge: Stock Assessment Program

Funded

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Theme 3. Sustainable fisheries
Goal H. Improve and implement stock assessments, based on the best available science
Target H.1. Undertake the research necessary to develop and conduct at least one benchmark stock assessment for yellowfin and bigeye tunas

Objectives

Improve the yellowfin tuna stock assessment by exploring alternative hypotheses of stock structure and life-history

Background

A benchmark assessment was conducted in 2020 with 48 models representing several hypotheses for the stock. The main overarching hypotheses, stock structure, was not possible to address extensively

Relevance for management

The stock assessment is used to provide management advice
The duration of recommended seasonal closures is based on risk analyses of bigeye and yellowfin that use the assessment results
Improvements in the yellowfin assessment will make the staff’s management advice more accurate and precise

Duration

2021-2024

Workplan and status

2021: Re-evaluate the natural mortality assumptions
2022-23: Explore different hypotheses on stock structure
2022: Workshops to finalize improvements to the longline CPUE and length-composition data (Projects H.1.e – ext and H.1.f)
2023: Re-evaluate the model assumptions and implement exploratory models
2024: Benchmark assessment

Deliverables

Report(s) to SAC in 2022, 2023 and 2024