Summary of toothfish tagging suitability data from paired Spanish line – trotline sets

Conservation Measure 41-01\Annex C requires participants in exploratory fisheries to only tag fish with a high probability of survival. Further it recommends that fish hooked only in the mouth should be tagged. A new data collection form was implemented in 2012 to allow evaluation of fish suitability for tagging from research hauls in exploratory fisheries in Subarea 58.4 and 48.6. We summarized these data and data from tag release forms to assess suitability of captured toothfish for tagging. Data were only available for trotline and experimental Spanish line - trotline gear. Fish suitability for tagging was most related to species, soak time, and fish size. For both gear types, an adequate number of suitable fish were available to tag. Further data collection from sets with different gear configurations and operational effects would be useful in a multivariate analysis to identify the factors affecting fish suitability for tagging. From paired sets in which Spanish and trotline gear types were deployed simultaneously, the trotline configuration had a higher catch rate overall for Patagonian toothfish. However, the relatively higher trotline catch rates degraded for small fish (less than 70 cm), and showed no difference in length selection over the rest of the sizes encountered.