1. Home
  2. Research
  3. Projects
  4. Develop a larval growth index to forecast yellowfin recruitment
Project G.3.a - Develop a larval growth index to forecast yellowfin recruitment

01 Jun 2018 - 01 Jun 2023

Program(s) in charge: Early-life History Group
Objectives
To develop a larval or early-juvenile growth index for yellowfin tuna in the Panama Bight which might prove useful as an index of recruitment strength of yellowfin in the EPO
Background
  • Growth rate variability in the larval and juvenile stages of pelagic marine fishes is substantial, and has strong potential to influence mortality patterns during pre-recruit life stages
  • Previous research by the Early Life History group has identified some local correspondence in the Panama Bight between high growth rates/densitydependence in growth of yellowfin larvae and recruitment estimates for yellowfin
  • Quarterly or seasonal nightlight surveys of early-juveniles in the Panama Bight are recommended at the Achotines Laboratory, with aging analysis conducted for growth rate estimation and comparison to quarterly recruitment estimates for yellowfin
Relevance for management
The development of a larval or early-juvenile growth index is promising as a forecasting tool for assessing yellowfin recruitment patterns.
Duration
4 years
Workplan and status
  • June 2012-December 2022: Conduct quarterly or seasonal nightlight surveys of yellowfin at the Achotines Laboratory
  • January 2022-June 2023: Conduct otolith aging analysis on field-caught fish
  • Analyze and compare growth data and recruitment estimates for yellowfin, and complete manuscript and submit to scientific journal
Deliverables
  • Presentations for SAC-09, SAC-10, SAC-11 and SAC-12
  • Publication of results in a scientific journal
Updated date: 01 Mar 2022
Progress summary for the reporting period
Analysis of in situ growth of yellowfin larvae and early-juveniles in relation to ocean temperature, availability of forage, larval density and availability of potential predators in nursery grounds in the Panama Bight, determined from past at-sea surveys at the Achotines Laboratory, is continuing during 2022.
Challenges and key lessons learnt
Funding has not yet been secured for the at-sea surveys and subsequent analyses necessary for the development of the growth index, but expansion of analysis of past in situ growth sampling is continuing in 2022.
Presentations:
  • SAC-09 (May 2018)
  • 42nd Larval Fish Conference (June 2018) and 43rd Larval Fish Conference (May 2019)
  • SAC-12-15 Review of research at the Achotines Laboratory