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A global assessment of the impact of fisheries-related mortality on shy and white-capped albatrosses: Conservation implications |
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| Authors: | G Barry Baker Michael C Double Rosemary Gales Cathryn L Abbott Samantha L Petersen Rachael Alderman |
| Institution: | a Institute of Antarctic and Southern Ocean Studies, University of Tasmania, Private Bag 77, Hobart, Tasmania 7001, Australia b School of Botany and Zoology, The Australian National University, Canberra, ACT 0200, Australia c Biodiversity Conservation Branch, Department of Primary Industries and Water, P.O. Box 44, Hobart, Tasmania 7000, Australia d CSIRO Marine and Atmospheric Research, GPO Box 1538, Hobart, Tasmania 7001, Australia e Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch 7701, South Africa f Responsible Fisheries Programme, Marine Programme, Birdlife South Africa, P.O. Box 52026, Waterfront 8002, South Africa g Wild Press, P.O. Box 12-397, Wellington, New Zealand |
| Abstract: | Hundreds of thousands of seabirds are killed each year as a result of interacting with longline and trawl fishing operations, and the severity of the impact varies regionally. Shy and white-capped albatrosses, Thalassarche cauta and Thalassarche steadi respectively, are phenotypically similar species known to be incidentally killed by fishing operations. The magnitude of this mortality has not previously been assessed across their range. Here we examine recent effort and bycatch rates in fisheries known to incidentally kill these species and qualitatively evaluate the level of impact of each fishery. Results indicate that over 8500 of these albatrosses may be killed annually, although the reliability of this estimate is low due to the paucity of comprehensive observer data in most fisheries. Of the estimated deaths of all seabird species in the fisheries assessed, trawl and longline fisheries killed birds in approximately equal proportions, but when the mortality levels of shy-type albatrosses were examined, trawl fisheries were responsible for 75% of all deaths. Data suggest most of these birds were killed in South African, Namibian and New Zealand demersal trawl fisheries and the South Africa pelagic longline fishery. Because most adult shy albatrosses are comparatively sedentary and rarely found outside Australian waters, it is primarily juvenile shy albatrosses that regularly encounter fishing fleets known to kill large numbers of albatrosses. In contrast, throughout most of their range juvenile and adult white-capped albatrosses are exposed to fisheries that collectively kill many thousands of these albatrosses each year. These data emphasise the urgent need for robust assessments of the impact of bycatch at a species and population level, and the urgent implementation of effective mitigation measures. |
| Keywords: | Trawl and longline fisheries Seabird bycatch Bycatch mitigation Thalassarche Albatross |
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