Skip to main content

    An exploration of the biological data used in the CCAMLR Subarea 48.3 Patagonian toothfish stock assessments

    Request Meeting Document
    Document Number:
    WG-SAM-2019/32
    Author(s):
    E. MacLeod, K. Bradley, T. Earl, M. Söffker and C. Darby
    Submitted By:
    Dr Chris Darby (United Kingdom)
    Approved By:
    Dr Chris Darby (United Kingdom)
    Abstract

    WG-FSA 2018 noted that changes in productivity parameters may impact assessment estimates and consequent management advice, and that these changes may be related to long-term environmental change. The Working Group recommended that key assessment parameters be reviewed and that changes in the fishery dynamics that would impact their estimation be explored.

    The biological productivity parameters in subarea 48.3 are analysed here, particularly whether the proportion of females in the catch, maturity at length, length-weight relationships and growth rates have changed over time and how the fishery dynamics impact parameter estimates. Variation in parameter estimates is noted but no systematic trends in growth or maturity through time, after the effects of confounding factors were included in the analysis.