Further applications of statistical catch-at-age assessment methodology to the 2J3K-O Greenland halibut resource

Abstract

The initial applications of statistical catch-at-age analysis to commercial catch and survey information in Butterworth and Rademeyer (2009a) are updated to take temporal variability in survey selectivity-at-age into account, and an associated updated Baseline assessment B2 is developed. Sensitivity of the results of B2 to a wide range of alternative specifications is explored. Generally results are more positive than for the most recent XSA assessment. However the SCAA results are not entirely satisfactory because of a conflict evident between survey trends and the proportions-at-age data, which underlies the wide-ish range of results that can be obtained. The overall impression gained from these analyses is that the status of the 2J3K-O Greenland halibut resource is less robustly determined than might be inferred from past XSA assessments.