ESR 13:1-16 (2010)  -  DOI: https://doi.org/10.3354/esr00309

At-sea distribution and diet of an endangered top predator: relationship between white-chinned petrels and commercial longline fisheries

Karine Delord1,*, Cédric Cotté1, Clara Péron1, Cédric Marteau1,3, Patrice Pruvost2, Nicolas Gasco2, Guy Duhamel2, Yves Cherel1, Henri Weimerskirch1

1Centre d’Études Biologiques de Chizé, UPR 1934 du Centre National de la Recherche Scientifique, 79360 Villiers-en-Bois, France
2Département Milieux et Peuplements Aquatiques, Muséum National d’Histoire Naturelle, UMR 5178 USM 401, CP26,
75231 Paris cedex 05, France
3Present address: TAAF, rue Gabriel Dejean, 97410 Saint Pierre, Ile de la Réunion, France

ABSTRACT: Incidental seabird mortality associated with longline commercial fishing is a worldwide conservation concern. To develop conservation strategies, it is essential to estimate the likelihood of seabird bycatch and the degree of overlap between birds’ foraging grounds and commercial fishing areas. We tracked 21 adult white-chinned petrels Procellaria aequinoctialis breeding on Kerguelen Island, southern Indian Ocean, during their breeding period in 2006 and in 2008. At-sea foraging distribution of white-chinned petrels was mainly confined to Antarctic waters. Commercial longline fisheries targeting toothfish were operating in both the French Exclusive Economic Zone and in other Commission for the Conservation of Antarctic Marine Living Resources areas during the study. We analysed concurrent data on the positions of both birds and vessels to estimate overlap. Static analysis using indices (home-range and utilization distribution overlap) revealed that, at a large scale, spatial and temporal overlap occurred, but varied among areas and with breeding stage. Dynamic analysis (detection of operating vessels respective to bird locations within a time/space window) revealed little overlap at a small scale. Our study revealed a mismatch between large- and small-scale overlap estimates, suggesting that birds and vessels occupy the same overall zone with infrequent co-occurrence (19% of birds in the vicinity of vessels). This result was confirmed by the relatively low occurrence of fishery-related items (4 to 22%) in chick food samples. However, given the large size of seabird populations, overall, large numbers of birds overlap with vessels, and management authorities should maintain and promote the implementation of strict mitigation measures to further reduce bycatch.


KEY WORDS: Satellite tracking · Toothfish longline fisheries · Petrel · Procellaria aequinoctialis ·Diet · Spatio-temporal overlap


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Cite this article as: Delord K, Cotté C, Péron C, Marteau C and others (2010) At-sea distribution and diet of an endangered top predator: relationship between white-chinned petrels and commercial longline fisheries. Endang Species Res 13:1-16. https://doi.org/10.3354/esr00309

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