Deutsch: Beifang / Español: Captura accesoria / Português: Fauna acompanhante / Français: Prise accessoire

Bycatch is the term for any marine species that is caught unintentionally while fishing for different target characteristics, or a different target species altogether.

It may also be 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."

Other possible uses of the term in fisheries are as follows:

• catch which is retained and sold, but 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 sea birds, sea turtles, marine mammals, and elasmobranchs