Working with mixed fisheries

Fisheries that catch more than one species at a time, often called mixed fisheries, require a different kind of management than fisheries that target and catch a single species.

In a single-species fishery, management is based on the amount of fish that can be harvested from a given population without overfishing. This concept is known as Maximum Sustainable Yield (MSY). There are many fisheries in the MSC program that are managed using MSY, such as certified tuna fisheries.

In a mixed fishery, management based on the MSY of just one of the caught species does not necessarily maintain all caught species at sustainable levels. The more species in the catch, the more costly and difficult it is to monitor and manage each one. Species in the catch can have different population numbers, breeding rates and some species might be more impacted by fishing than others.

In addition, different species often interact with each other. For example, if one species is the predator or prey of another then harvesting one will probably affect the abundance of the other.

MSC requirements for mixed fisheries

Currently the MSC Fisheries Standard requires every species that is caught to be assessed. For some fisheries this can involve over a dozen species.