Seabird interactions with coastal fisheries in northern Patagonia: use of discards and incidental captures in nets

YORIO, P.; CAILLE, G.

WATERBIRDS (DE LEON SPRINGS, FLA.)

WATERBIRD SOC

Año: 1999 vol. 22 p. 207 - 216

1524-4695

Between November 1994 and May 1996, observations on the interactions between seabirds and trawl vessels were conducted at five Patagonian coastal fisheries between 41° and 52° S. Twenty- three seabird species used food made available by fishing operations. Mean number of species recorded per day varied between 2.5 and 6, depending on the fishery, and was significantly lower at the Bahía Engaño area. The highest number of species (17) was observed at the Golfo San Matías area. Kelp Gulls (Larus dominicanus) and Black-browed Albatrosses (Diomedea melanophris) were the most important seabirds, both in frequency of occurrence and numbers, followed by White-chinned Petrels (Procellaria aequinoctialis) or South American Terns (Sterna hirundinacea), depending on the fishery. Kelp Gulls were present between 91.6 and 100% of days at all fisheries except for Bahía Grande (28.6%), with numbers which varied between a few and 600 birds (means between 148.2-178.8 birds). Black-browed Albatrosses were present between 92.2 and 100% of days at all fisheries except for Bahía Engaño (7.3%), with numbers that varied between one and 375 birds (means between 53.7-123.7 birds). Most other species were either present in small numbers or were rarely observed. Seabirds obtained prey during discarding activities or from the net during haulback and prey brought to the surface during towing. Seabird mortality as a result of incidental captures was very low, with only one Imperial Cormorant (Phalacrocorax atriceps) and one Magellanic Penguin (Spheniscus magellanicus) killed during 394 hauls at 124 trips in the five fishing areas. Coastal trawl fisheries appear to have a small impact on Patagonian seabirds in terms of incidental mortality, but might have a significant effect through the provision of fishing waste, especially for Kelp Gull and Black-browed Albatross populations. Further information is needed to fully understand potential effects, as despite current increases in total catch at most fishing areas, changes in coastal fishing practices might result in a decrease of fish waste available