Sivusaalis

Sivusaalis is a term used in Finnish fisheries to describe the portion of a fishing operation’s catch that is not the intended target species. It consists of non-target species, undersized individuals of target species, and sometimes protected or non-commercial species that are caught unintentionally by the gear. The composition of sivusaalis depends on the fishing method (for example trawls, gillnets, longlines, or pots), the species present in the area, and the season.

In practice, sivusaalis can include various marine organisms such as juvenile fish, non-target fish species, crustaceans, and occasionally seabirds or marine mammals if interactions occur with certain gear types. The term emphasizes incidental catch rather than deliberately sought species, and its magnitude is influenced by gear selectivity and fishing practices.

Regulation and management of sivusaalis aim to reduce ecological impacts and improve stock assessments. Measures include gear improvements and selective devices to exclude non-target species, time and area closures, and monitoring programs. In the European Union, the landing obligation requires most catches to be landed and recorded, reducing the practice of discarding sivusaalis and enabling better data for stock management. Some bycatch may be regulated with specific quotas or prohibited completely, especially for protected species. Where bycatch cannot be landed, it must be returned to the sea following species-specific handling rules.

Etymologically, sivusaalis combines sivu meaning “side” and saalis meaning “catch,” reflecting its status as the incidental catch alongside the main target catch.