Bycatch

Bycatch is the accidental capture of animals in fishing gear. Bycatch has been reported for most marine mammal species and in many different types of fishery with estimates of total annual deaths of over 300,000 marine mammals. It is often poorly quantified, but even apparently low levels of bycatch can have severe impacts on marine mammal populations. Bycatch was a leading factor in the demise of the baiji or Chinese river dolphin. It is a major source of mortality for several other marine mammal species, and a leading conservation concern that threatens several species and populations. It also presents significant welfare concerns. Resolving bycatch issues is difficult because little is known about how or why marine mammals become ensnared. Some solutions have been developed, including acoustic warning devices, physical exclusion devices, and the use of alterative gear types, but there is no single simple solution.