Summary of intersessional work completed with stock synthesis projections to evaluate a subset of the 2017 conservation measures recommended by ICCAT, related to tac and size limits, to reduce mortality for north Atlantic shortfin mako

Stock Synthesis projections at alternative fixed total allowable catch (TAC) limits were implemented for the base case model (run 3) to evaluate the effectiveness of a subset of the 2017 conservation and management measures, size limits to protect immature shortfin mako, recommended by ICCAT to reduce North Atlantic shortfin mako shark mortality in association with ICCAT fisheries and to rebuild the stock to the MSY level. The projected recovery of spawning stock size was accelerated under size limits, but did not reach the MSY level by 2070 (two generations) even with size limits and a fixed TAC set to zero. These results suggest that while TAC and size limits are useful to reduce mortality, these management measures may be insufficient to rebuild the stock to the target level within the ICCAT time frame. In consideration of the nature of the fisheries for shortfin mako (i.e. bycatch species) and recent high level of the annual catches (around 3000 t), other proposed management measures, such as live release, may be practical measures to reduce fishing mortality.