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Seabird use of discards and incidental captures at the Argentine hake trawl fishery in the Golfo San Jorge, Argentina

2006; Inter-Research; Volume: 316; Linguagem: Inglês

10.3354/meps316175

1616-1599

Diego González-Zevallos, Pablo Yorio,

Wildlife Ecology and Conservation

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 316:175-183 (2006) - doi:10.3354/meps316175 Seabird use of discards and incidental captures at the Argentine hake trawl fishery in the Golfo San Jorge, Argentina Diego González-Zevallos1, Pablo Yorio2,* 1Universidad Nacional de la Patagonia, Bv. Brown 3700, 9120 Puerto Madryn, Chubut, Argentina 2Centro Nacional Patagónico (CONICET) and Wildlife Conservation Society, Bv. Brown 3500, 9120 Puerto Madryn, Chubut, Argentina *Email: yorio@cenpat.edu.ar ABSTRACT: We studied discard use and incidental mortality of seabirds attracted to high-sea trawl vessels operating in the Golfo San Jorge, Argentina, during the height of the fishing season in 2003 and 2004. Fourteen seabird species ate food made available by fishing operations. The most frequent and abundant seabirds (percent occurrence, mean number per haul) were the kelp gull Larus dominicanus (98.9%, 207.0), the black-browed albatross Thalassarche melanophrys (98.9%, 94.2) and the white-chinned petrel Procellaria aequinoctialis (91%, 8.4). Flock sizes for the 3 species varied from a few to a maximum of 1600 birds. Total seabird abundance varied significantly between stages of the fishing operation, being higher during discarding and haulback than during towing. Incidental capture of seabirds in nets was recorded in 37% of 89 hauls, with a mean capture rate of 1.2 birds per haul. Species incidentally caught were the great shearwater Puffinus gravis, the imperial cormorant Phalacrocorax atriceps and the Magellanic penguin Spheniscus magellanicus, with rates that varied between months and years. Considering the fishery's fishing effort, the estimated total numbers of birds killed during the study were 2254 great shearwaters (CV = 1.1), 1233 imperial cormorants (CV = 1.1) and 35 Magellanic penguins (CV = 2.4) in 2003, and 311 imperial cormorants (CV = 1.7) and 1516 Magellanic penguins (CV = 1.1) in 2004. Black-browed albatrosses and kelp gulls were also struck by the warp cable while feeding on discards from the surface, and drowned when they were dragged underwater. The results obtained in this study show that the hake trawl fishery operating in the Golfo San Jorge may have a significant effect on some seabird populations through the provision of fishing discards and incidental mortality. KEY WORDS: Seabird–fishery interactions · Discards · Incidental mortality · Trawl fisheries Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 316. Online publication date: July 03, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.