What is "bycatch"

n. Any fish (or other creatures) that are not targeted as a catch but are unintentionally caught, and often discarded back into the se

1. v

2. (context transitive English) To catch unintentionally while fishing for something else.

n. unwanted marine creatures that are caught in the nets while fishing for another species; "thousands of dolphins and porpoises and whales are killed as part of the by-catch each year" [syn: by-catch]

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.

In 1997, the Organisation for Economic Co-operation and Development (OECD) 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 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:

• Catch which is retained and sold but which is not the target species for the fishery
• Species/sizes/sexes of fish which fishermen discard
• Non-target fish, whether retained and sold or discarded
• Unwanted invertebrate species, such as echinoderms and non-commercial crustaceans, and various vulnerable species groups, including seabirds, sea turtles, marine mammals and elasmobranchs (sharks and their relatives).