Estimating by-catch from CCAMLR data

Quantifying the catch rates and biomass of by-catch species on CCAMLR’s fishing grounds is an essential component of the assessment advice prepared by WG-FSA. However, such analyses are problematic because the CCAMLR datasets are incomplete and have a high occurrence of ‘missing catch values’.
A method to treat ‘missing catch values’ using estimates derived from the mean weights of by-catch species by fishing gear, region and period is outlined. This method would improve the consistency of the CCAMLR datasets and allow quantitative analyses of by-catch to be based on the best, scientific data available.