Can modelling the drift of bycaught dolphin stranded carcasses help identify involved fisheries? An exploratory study. Submitted to Biol. Cons.
HÃƒÂ©lÃƒÂ¨ne Peltier, Willy Dabin, CÃƒÂ©cile Dars, Fabien Demaret, Ghislain Doremus, Olivier van Canneyt, Sophie Laran, Paula Mendez-Fernandez, JÃƒÂ©rÃƒÂ´me Spitz, Matthieu Authier, Pierre Daniel and Vincent Ridoux
The aim of this work is to test an approach that would help to identify the fisheries potentially involved in any given stranding events. To do this we examined how the likely distributions of mortality of bycaught dolphins inferred from carcass drift modelling coincide with fishing effort statistics in the same area at the same dates for different fleets, generated from the Vessel Monitoring System. Using reverse drift modelling, two main mortality areas were identified during these events, and 3 690 common dolphins (IC95% [2 230; 6 900]) were estimated to have died in fishing gears of the Bay of Biscay during February and March 2017. The relationship between origin of stranded bycaught dolphins and fishing effort distribution during the different stranding events was strongly positive for French midwater pair trawlers, Spanish otter bottom trawlers and French Danish seiners. Co-occurrence highlights a risk but does not presume of interaction of fishing effort on common dolphins nor its intensity.