Seabird Interactions with Coastal Fisheries in Northern Patagonia: Use of Discards and Incidental Captures in Nets

Between November 1994 and May 1996, observations on the interactions between seabirds and trawl vessels were conducted on 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 in 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. 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 on 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. /// Entre Noviembre de 1994 y Mayo de 1996 se efectuaron observaciones sobre las interacciones entre aves marinas y barcos de arrastre en cinco pesquerías costeras Patagónicas. Veintitrés especies de aves marinas aprovecharon el alimento provisto por las operaciones pesqueras en todos los caladeros. El número medio de especies registradas por día varió entre 2.5 y 6, dependiendo de la pesquería. El mayor número de especies (17) se registró en el Golfo San Matías. La Gaviota Cocinera Larus dominicanus y el Albatros Ceja Negra Diomedea melanophris fueron las aves marinas más importantes en las flotas costeras, tanto en frecuencia de ocurrencia como en abundancia, seguidas por