FEATURES OF SEABIRD INTERACTION WITH TRAWL FISHING GEAR

Abstract

Seabirds interaction with trawl fishing gear was observed aboard the large freezing-processing trawler «Moskovskaya Olimpiada» during the pollock fishery in the Okhotsk Sea in January-April, 2015. In total, 579 observation rounds were realized including 105 ones during the trawl setting, 116 ones during hauling, and 358 ones during trawling, with total duration of 280.7 hours. In the observations, 1443 contacts of birds with the fishing gear were recorded. Light contact of a flying gull with the trawl net was observed in one case only; all other contacts were collisions with the wires. The warps and the depth sounder cable were the greatest hazard for birds. Collisions with the sounder cable during the trawling were the most frequent, with approximately 5 times higher frequency than with the same cable during the trawl setting or hauling. Almost all strikes with the wires were registered for northern fulmars (97.5 %) and the rest of the strikes — for large gulls. Gulls had only light contacts with the depth sounder cable (2 contacts afloat and 34 contacts in flight). Fulmars had contacts both with the depth sounder cable and warps. Flying birds of this species contacted with the depth sounder cable more frequently (75.5 %) than those sitting on the water. On the contrary, majority of fulmars (61.6 %) contacted with the warps being afloat in the process of their feeding. Several cases only (0.6 %) of direct interactions with the fishing gear caused the bird’s death. All these cases occurred with the fulmars drowned when they fell under the depth sounder cable (7 ind.) or under the warp (1 ind.). Frequency of the bird collisions with the wires differed prominently by the fishery districts, with the maximum in the Kamchatka-Kuril subzone (8.35 contacts/hour for fulmars and 0.22 contacts/hour for gulls). These spatial differences are related to the birds abundance near the ship that depends on distribution patterns of certain bird species in the Okhotsk Sea in winter. General frequency of the contacts depends credibly on intensity of the waste discharges after fish processing and on wind direction relative to the ship course.