Benthic Habitats and the Effects of Fishing

Fishing Impacts on Irish Deepwater Coral Reefs: Making a Case for Coral Conservation

Anthony J. Grehan, Vikram Unnithan, Karine Olu-Le Roy, and Jan Opderbecke

doi: https://doi.org/10.47886/9781888569605.ch144

Abstract. Deepwater coral reefs, formed principally by the azooanthelate scleractinian Lophelia pertusa , occur off the western coast of Ireland in water depths of 500 to 1,200 m. They are found in association with provinces (clusters) of giant carbonate mounds which rise 10 to 300 m above the seafloor. These reefs are home to a rich associated invertebrate and fish fauna. Pressures on the coral habitat are increasing with trawling in Norway, estimated to have damaged 30% to 50% of known reefs and significantly impacted coral locations west of Scotland. Concerns over potential further damage to corals prompted a consortium of Irish and European scientists to begin a detailed European Unionfunded environmental baseline study (the Atlantic Coral Ecosystem Study) of the coral ecosystem where it occurs along the Atlantic Margin. In summer 2001, a French-Irish-European Union research mission CARACOLE (Carbonate Mound and Cold Coral Research) visited five deepwater coral locations in the Irish Porcupine Seabight and Rockall Trough. High-resolution video and close-up digital stills taken with the French VICTOR remotely operated vehicle revealed the extensive and spectacular nature of the coral reef formations. Evidence of fishing activity was confined to imaging of static gears (gill and tangle nets) used to fish for monkfish or anglerfish Lophius spp. and hake Merluccius merluccius lost on the side of mounds. No evidence of trawl-related damage to the corals was obtained even though coral bycatch has been reported from several deepwater trawl surveys in Irish water over the years. However, recent expansion of a deepwater trawl fishery, principally for orange roughy Hoplostethus atlanticus , highlights the urgent need for more focused investigations of fishing impacts and the rapid implementation of conservation measures to protect the corals. The designation of coral Special Areas of Conservation under the European Union Habitats Directive and their subsequent management will provide a rigorous test of the commitment of the European institutions to improve environmental integration implicit in the recent reform of the European Common Fisheries Policy.