WP 3: Habitat functions in relation to fish and food webs – from point observations to management

The key to ecosystem-based management is to understand how the habitat supports species that live there, providing access to food, shelter, spawning grounds and nursery areas. In this work package we will study sandbanks and bivalve reefs formed by horse mussels and blue mussels. Which services do these habitats offer marine life?

Sandbanks come in many forms and are found at different depths. Among other things, they are important hiding places for sandeel  and spawning grounds for herring. The movement of ocean currents and the size of the sand grains are examples of details that can be important for these species. How large must a protected area be to ensure enough sandeel to support the food chain? Sand extraction from the seabed is an example of a threat to these areas.

The mussel reefs are home to many small animals such as snails, shrimps and crabs, and are believed to also provide nursery and habitat for many fish species, including vulnerable species, such as sharks and skates. Mussel reefs are in decline, but to what extent is still unknown.

Four years of sampling sand and gravel banks in the north-eastern North Sea has provided new insight on the communities of juveniles and small fish species inhabiting these habitats. In parallel, we are undertaking a large systematic literature review to uncover all existing knowledge about fish inhabiting sand and gravel habitats and mussel reefs in east Atlantic waters. We hope to report fresh results from these studies later this year.