Cetacean bycatch (or cetacean by-catch) is the accidental capture of non-target cetacean species such as dolphins, porpoises, and whales by commercial fisheries.[1] Bycatch can be caused by entanglement in fishing nets and lines, or direct capture by hooks or in trawl nets.
Cetacean bycatch is increasing in intensity and frequency.[2] This trend is likely to continue because of population growth and demand for marine food sources, as well as industrialization of fisheries as they expand into new areas. These fisheries come into both direct and indirect contact with cetaceans. An example of direct contact is the physical contact of cetaceans with fishing nets. Indirect contact occurs through marine food chains, whereby fisheries severely reduce fish stocks that cetaceans rely on for food. In some fisheries, cetaceans are captured as bycatch but then retained because of their value as food or bait.[3]