Variation in indices of tag reporting rate in the British Columbia Sablefish (Anoplopoma fimbria) fishery

Mathematical models in fisheries research that utilize tag return data require an estimate of the proportion of commercially caught tags that are returned (i.e., the tag reporting rate). In this study, I estimated an index of tag reporting rate in the British Columbia Sablefish fishery by comparing the prevalence of tags in the commercial fishery catch to the tag prevalence of a fishery-independent survey. I determined the effect of region, year, gear type, and size by fitting generalized linear models to the estimates of this index. The tag reporting rate index varied across size classes and gear types, with high indices of tag reporting rate for fish larger than the commercial size limit, and in the trap fishery. I concluded that factors such as gear selectivity and handling of catch are likely impacting the indices of tag reporting rate. Future studies could investigate the drivers of variation in the index of tag reporting rate and seek to identify sources of bias. Potential clustering of tagged fish should also be investigated.