Observed live releases and dead discards of shortfin mako shark (Isurus oxyrinchus) from Canadian fisheries

Information on the magnitude and condition (alive, dead) of discards of shortfin mako shark (Isurus oxyrinchus) from Canadian fisheries has not been previously reported. Here, we have compiled observer records from 1987 – 2016 as a first summary of the magnitude of by-catch in Canadian fisheries operating within and outside of Canada’s Exclusive Economic Zone. Years in which these data are not complete or are influenced by inaccurate species identification or non-reporting are identified. Totals are split into live releases and dead discards based on gear-specific mortality rate estimates. No attempt has been made to scale up observed discards to fleet-wide totals, which remains an ongoing research area.