Preliminary sustainability assessment for fishing effects (safe) of pelagic longline fisheries on porbeagle sharks and identification of f-based biological reference points

A Sustainability Assessment for Fishing Effects (SAFE) was conducted for the porbeagle shark in the North and South Atlantic oceans. The SAFE approach is a quantitative assessment that computes a proxy for fishing mortality rate as the product of four susceptibility components: availability of the species to the fleets, encounterability of the gear given the species vertical distribution, gear selectivity, and post-capture mortality. The information used to compute the four components came from several sources: observer programs from several ICCAT fleets (capture location, size, status, and disposition of observed animals, vertical distribution of the gear), archival tags from various ongoing projects (distribution, vertical habitat use, and postrelease mortality), and ICCAT catch and effort data. The product of these four components was used to compute a harvest rate that can be expressed as F (instantaneous fishing mortality rate) and compared to a value of FMSY obtained based on productivity values derived exclusively from life history data. Results suggest that the porbeagle in the North and South Atlantic are not undergoing overfishing.