Workshop to evaluate differences in bigeye tuna age estimation methods and resulting growth models utilized in current stock assessments by the IATTC and WCPFC

Project E.2.b - Workshop to evaluate differences in bigeye tuna age estimation methods and resulting growth models utilized in current stock assessments by the IATTC and WCPFC

23 Jan 2019 - 25 Jan 2019

Completed

Program(s) in charge: Life History and Behavior Group

Funded

Click to see projects by theme, goal or target:

Theme 2. Life history studies for scientific support of management
Goal E. Obtain life history and stock structure information for spatially-structured stock assessments for tropical tunas
Target E.2. Conduct spatiotemporal research on the reproductive biology of tropical tunas

Objectives: Resolve concerns about differences in age estimation methods and resulting growth models used in bigeye tuna stock assessments by IATTC and WCPFC
Background: Although there are documented differences in the life history characteristics of the bigeye stocks from the EPO and WCPO, the magnitude of the discrepancies in the estimated length-at age data, growth models, and L∞ estimates used in the recent IATTC and WCPFC stock assessments, along with the dramatic shift in stock status of WCPO bigeye population is concerning. The estimated L∞ from the WCPO bigeye growth model is 157 cm, unrealistically low, and is highly influential in the assessment model and resulting stock status determination.
Relevance for management: Age and growth models and their estimates of L∞ are highly influential in assessing the status of bigeye in integrated assessment models
Duration: 2 days
Workplan and status: Workshop to be held in La Jolla, November 2018, or as soon as possible in 2019
External collaborators: SPC; CSIRO and FAS, Australia; FSFRL, Japan; PIFSC
Deliverables: A workshop report to be shared with all interested parties