Mitigating bycatch and depredation of marine mammals in longline fisheries

This study provides a summary of methods that can be used to reduce depredation and bycatch of marine mammals in longline fisheries. Methods include 1) spatial management methods, 2) acoustic methods, 3) physical methods and 4) 'other methods'. The results indicate that some methods can be used with both pelagic and demersal longlines, while others can be used with only one or the other. In addition to the methods investigated, the results highlight significant knowledge gaps.These include survivability after hooking and entanglement. This lack of information hinders assessing serious injury and mortality to marine mammals after interactions with longline fisheries occur. The development of deterrents would also be improved with increased knowledge of marine mammal behavior near longlines.