Studies on Echolocation of Porpoises Taken in Salmon Gillnet Fisheries

In the Bering Sea, marine mammals, particularly Dall’s porpoises, Phocoenoides dalli, get incidentally entangled in gillnets of the Japanese mothership salmon fishery. The maximum total number of Dall’s porpoises to be caught in a year was fixed by U.S. law. In order to develop techniques and devices to reduce the incidental catch in the gillnets, it is necessary to learn why and how they get entangled.