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Project E.5.a - Evaluate the Pacific-wide population structure of bigeye and skipjack tunas, using genetic analyses

01 Jan 2017 - 31 Dec 2020

Program(s) in charge: Life History and Behavior Group
Funded
Objectives
Determine whether bigeye and skipjack tuna from discrete areas of the Pacific Ocean show significant genetic heterogeneity
Background
  • Genetic studies can be used to evaluate and validate the results of tagging experiments
  • Modern genetic analyses can be used to assess genetic heterogeneity between tropical tuna stocks
  • Data from tagging experiments and genetic studies can inform spatiallystructured stock assessments
Relevance for management
Spatially-structured stock assessments based on geographically-explicit life history parameters will provide a more accurate basis for the staff’s management advice
Duration
5 years (2017-2021)
Workplan and status
  • 2017-2019: Tissue samples from the Pacific and other oceans processed at CSIRO using genotyping and sequencing techniques
  • 2018-2021: Analyses of genetic data at CSIRO with software specifically designed for uncovering and evaluating genetic heterogeneity in population structure
  • 2022: Some sample cross contamination identified during analyses and resampling efforts began during Q4:2022
  • 2022: Manuscript in preparation on assessment of skipjack population structure from samples from Indian Ocean, western and eastern Pacific.
  • 2022: Manuscript in preparation on assessment of bigeye population structure from samples from western, central, and eastern Pacific
External collaborators
CSIRO, Hobart, Australia
Deliverables
  • Relevant information on population structure of bigeye and skipjack tunas in the Pacific for informing future stock assessments
  • Manuscripts for publication in scientific journals
Updated date: 01 Dec 2022
Progress summary for the reporting period
  • CSIRO processed additional tissue samples from the Pacific Ocean
  • CSIRO conducted updated analyses of genetic data sets, including additional tissue samples Interpretation of results is being finalized
  • CSIRO identified deficiencies in some EPO samples and resampling efforts have begun
Challenges and key lessons learnt
  • Collections, processing, and analyses of suitable numbers of tissue samples for assessing population structure of tunas takes considerable time and effort.
  • Preparations of manuscripts describing population structure of bigeye and skipjack tunas takes considerably longer than anticipated
  • Samplers need to be cautious to avoid issues with sample contamination.
  • Manuscripts in preparation on Pacific-wide population structure of bigeye and skipjack tuna