page_title: Bycatch
section_title: Cetacean
hierarchical_section_title: Bycatch / Examples / Cetacean
context_page_description: Bycatch, in the fishing industry, is a fish or other marine species that is caught unintentionally while catching certain target species and target sizes of fish, crabs etc. Bycatch is either of a different species, the wrong sex, or is undersized or juvenile individuals of the target species. The term "bycatch" is also sometimes used for untargeted catch in other forms of animal harvesting or collecting. Non-marine species that are caught but regarded as generally 'undesirable' are referred to as rough fish and coarse fish.
  In 1997, the Organisation for Economic Co-operation and Development defined bycatch as "total fishing mortality, excluding that accounted directly by the retained catch of target species". Bycatch contributes to fishery decline and is a mechanism of overfishing for unintentional catch.
  The average annual bycatch rate of pinnipeds and cetaceans in the U.S. from 1990 to 1999 was estimated at 6215 animals with a standard error of 448.
  The fisherman bycatch issue originated due to the "mortality of dolphins in tuna nets in the 1960s".
  There are at least four different ways the word "bycatch" is used in fisheries:
context_section_description: Cetaceans, such as dolphins, porpoises, and whales, can be seriously affected by entanglement in fishing nets and lines, or direct capture by hooks or in trawl nets. Cetacean bycatch is increasing in intensity and frequency. In some fisheries, cetaceans are captured as bycatch but then retained because of their value as food or bait. In this fashion, cetaceans can become a target of fisheries.
  One example of bycatch is dolphins caught in tuna nets. As dolphins are mammals and do not have gills they may drown while stuck in nets underwater. This bycatch issue has been one of the reasons of the growing ecolabelling industry, where fish producers mark their packagings with disclaimers such as "dolphin friendly" to reassure buyers. However, "dolphin friendly" does not mean that dolphins were not killed in the production of a particular tin of tuna, but that the fleet which caught the tuna did not specifically target a feeding pod of dolphins, but relied on other methods to spot tuna schools.
  The bycatch of the Caspian seal may be recognized as the one of the biggest entanglements of pinnipeds as bycatch in the world
caption: Group of Fraser's dolphins.
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