Shellfish reefs are some of the most important habitats in the marine ecosystem. These important reef systems provide habitats and homes for many other marine organisms such as anthozoans, hydrozoans, bivalves, echinoderms and ascidians.
Specifically, shellfish reefs formed by the horse mussel Modiolus modiolus (L.) have been identified as “biodiversity hotspots” and “priority habitats”, and as such are important to the “development of conservation management policy “ and indicators for Good Environmental Status (GES) under the EU Marine Strategy Framework Directive.
Unfortunately about 85% of the world’s shellfish reefs have been lost to destructive fishing practices such as trawling and dredging, overharvesting, introduction of non-native shellfish, habitat loss and decline in water quality. A study by Robert Cook and colleagues found that after a single trawl there was a 90% decrease in the abundance of epifaunal organisms and after a dredge a decrease of 59%. Further, after returning to the same sites a year later it was evident that barely any of the infaunal taxa had recovered. In the past indirect studies have shown declines of shellfish reefs in fishing grounds, but this study directly shows the link between destructive fishing practices and degradation of habitats and the negative effects on fauna.
For more information read the entire study here.