Preliminary results from an updated assessment of the squid resource
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2010
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University of Cape Town
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A Bayesian analysis, to take full account of model uncertainty, was conducted in the past to assess the status of the squid resource Loligo reynaudii. The data included in the analysis comprised jig catches (1983-2002), trawl catches (1971-2002), jig CPUE (1985-2002), trawl CPUE (1978-1999), an autumn survey biomass index (1988-1997, 1999) and a spring survey biomass index (1987, 1990-1995, 2001). Twelve models, each assuming a discrete value for h (the steepness parameter in the stock-recruit relationship), ranging from 0.40 – 0.95 in units of 0.05, were run and results were integrated over these models. Subsequent to the presentation of the results from the above-mentioned analysis, additional data have become available and there have also been some modifications made to the input data. Time constraints have precluded conducting a complete reanalysis whereby the results are integrated over the 12 models that were previously considered, where each model assumed a discrete value for steepness h. This paper therefore compares results for the assessment model utilizing i) the previous data and ii) the updated data for one of the models considered, namely h=0.7. It is therefore important to note that the results presented here are a work in progress and will be subject to a fuller evaluation in the near future.
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Glazer, J. P., & Butterworth, D. S. (2010). Preliminary results from an updated assessment of the squid resource. MCM/2010/APR/SWG-SQ/08