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The deep-water coral Lophelia pertusa in Norwegian waters: distribution and fishery impacts - page 5 / 12





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Figure 3. Sørmannsneset on Storegga shelf break. Filled circles; presence of corals; stars; damaged corals reported by fishermen; open circles; ROV inspections.

rarely found (Fig. 4). We encountered many signs of human activity: lost gillnets, an anchor, wires, a buoy, and remains of a trawl net entangled with corals. In addition, sonargrams from the side scan sonar detec- ted furrows penetrating into areas of damaged corals (Fig. 5). We interpret these furrows as caused by trawl doors or other parts of a trawl gear cutting through the surface of the bottom. On the other hand, well- developed, seemingly intact, coral reefs were observed in the deepest parts although they were not abundant.


Korallneset used to be a good coral locality, but heavy trawling has reduced the corals considerably, the fish- ermen claim. However, they also report a number of areas with undamaged corals. At Korallneset nearly 2.6 km of the sea bottom was inspected between 305 and 205 m depth. Almost all corals observed were crushed or dead.


Aktivneset is subject to heavy trawling and fisher- men report damaged reefs in the shallow parts al- though many corals are still undisturbed. One fisher- man claims he has detected large coral reefs on the echosounder.

The ROV inspection showed this location to be very rich in corals all along the 7 km ROV transect between 350 and 270 m depth. The reefs were neither large nor high, but smaller colonies covered significant

areas. However, damage was evident as well as signs of human activity such as a rubber boot, ghostfishing gillnets and furrows in the bottom sediments.


Similar report as from Korallneset: an area previously considered a good fishing ground, but that has been ‘cleaned for corals’ due to heavy trawling activity. Damage is severe, especially on the slopes of a smaller basin or depression in the shelf. The video inspection on mounds in the basin showed intact coral reefs in considerable quantities. The trawled area on the slope and on the flats around the basin was not inspected because the ROV broke down, so fisherman reports could not be checked.


We repeatedly received alarming information from fishermen claiming that extensive areas with promin- ent coral reefs had disappeared after heavy trawling activity. They affirmed that these reefs were notably well developed on a slope rising from a plain at ap- proximately 300 m depth to 134 m. Five inspections revealed severe damage to colonies of Lophelia and other corals such as gorgonians (Figs. 6–8). Every in- spection verified damage to corals that exhibited all stages of degradation, e.g., from almost intact liv- ing coral colonies to completely crushed reefs. The packed dead coral fragments forming the base of nat-

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