Acoustic methods of reducing or eliminating marine mammal-fishery interactions: do they work?

A summary study of methods used to reduce or eliminate marine mammal entanglements was conducted. The authors found little evidence on the effectiveness of the use of sound to reduce or eliminate marine mammal incidental capture. Substantial decreases in cetacean bycatch, due to the use of passive methods such as increasing fishing net reflectivity, were not evident through comparisons of catch rates in commercial fisheries or from observational deterrence studies. Net alarms have been shown to greatly reduce whale entrapment in Canadian fish traps but similar success has not been shown in reducing small cetacean bycatch in many gillnet fisheries. Few controlled studies on the use of sound to reduce or eliminate marine mammal interactions have been conducted. There is a need to additional basic research on echolocation behavior and behavioral interactions between marine mammals and fisheries.