Evidence of major fisheries impact on cold-water corals in the deep waters off the Porcupine Bank, west coast of Ireland: are interim management measures required?

Measures to conserve representative examples of cold-water coral reefs in Ireland through the designation of sites as Special Areas of Conservation (SACs) under the EC Habitats Directive are underway. However, evidence of damage to corals by fishing obtained during the RV Polarstern expedition ARK XIX Leg 3A to the Porcupine Sea Bight and Bank during summer 2003 suggest that more immediate management measures are required. A total of 9 dives were carried out with the IFREMER deep-sea VICTOR 6000 Remotely Operated Vehicle (ROV) on carbonate mound and deep-water coral locations in the study area. High resolution video and close-up digital stills were used to document the impact of fishing activity and the presence of lost gears. A series of mounds and scarps investigated along the western edge of the Porcupine Bank, in water depths of 600-1000m, were most severely impacted. One double mound system, named the Twin Mounds, appeared to be heavily trawled, as evidenced by the presence of trawl scars, barren sediment and flattened coral rubble. On the nearby Giant Mound, images of lost trawl gear filled with coral (some of it still living), provided clear evidence that reefs are being destroyed by present fishing activities. The results presented provide irrefutable proof of a serious threat from current fishing practices to the physical integrity of the pristine and physically complex deep-water coral ecosystem. The need for interim measures to protect deep-water corals in the period before SAC designation becomes effective is discussed.