When purse seining for herring, catch regulation has traditionally been done by discarding all or part of the catch if it is too big, or if the size or quality of the herring does not match requirements. Net burst is also quite common. Experiments have shown that mackerel is vulnerable to crowding. The mortality rates become unacceptably high in short time. It has been speculated that this may also be the case for herring.

- Research is the main pillar in sustainable management, said Helga Pedersen, Minister of Fisheries and Coastal Affairs, when she spoke to the Norwegian Fishboat Owners` Association in Oslo.