Importance of toothfish in the diet of generalist subantarctic killer whales: implications for fisheries interactions

Tixier, Paul, Giménez, Joan, Reisinger, Ryan R., Méndez-Fernandez, Paula, Arnould, John P. Y., Cherel, Yves and Guinet, Christophe 2019, Importance of toothfish in the diet of generalist subantarctic killer whales: implications for fisheries interactions, Marine ecology progress series, vol. 613, pp. 197-210, doi: 10.3354/meps12894.

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Title Importance of toothfish in the diet of generalist subantarctic killer whales: implications for fisheries interactions
Author(s) Tixier, PaulORCID iD for Tixier, Paul orcid.org/0000-0002-7325-3573
Giménez, Joan
Reisinger, Ryan R.
Méndez-Fernandez, Paula
Arnould, John P. Y.ORCID iD for Arnould, John P. Y. orcid.org/0000-0003-1124-9330
Cherel, Yves
Guinet, Christophe
Journal name Marine ecology progress series
Volume number 613
Start page 197
End page 210
Total pages 14
Publisher Inter-Research Science Publisher
Place of publication Oldendorf, Germany
Publication date 2019-03
ISSN 0171-8630
Keyword(s) Science & Technology
Life Sciences & Biomedicine
Physical Sciences
Ecology
Marine & Freshwater Biology
Oceanography
Environmental Sciences & Ecology
Diet
Fisheries
Southern Ocean
Killer whale
Stable isotopes
Fishery interactions
ORCINUS-ORCA
PATAGONIAN TOOTHFISH
STABLE-ISOTOPE
SOUTHERN-OCEAN
CROZET ARCHIPELAGO
LIPID EXTRACTION
FEEDING ECOLOGY
MARINE MAMMALS
BLUEFIN TUNA
SPERM-WHALES
Summary © 2019 Inter-Research. All Rights Reserved. Fisheries may generate new feeding opportunities for marine predators, which switch foraging behaviour to depredation when they feed on fish directly from fishing gear. However, the role of diet in the propensity of individuals to depredate and whether the depredated resource is artificial or part of the natural diet of individuals is often unclear. Using stable isotopes, this study investigated the importance of the commercially exploited Patagonian toothfish Dissostichus eleginoides in the diet of generalist subantarctic killer whales Orcinus orca depredating this fish at Crozet (45°S, 50°E). The isotopic niche of these killer whales was large and overlapped with that of sperm whales Physeter macrocephalus from the same region, which feed on toothfish both naturally and through depredation. There was no isotopic difference between killer whales that depredated toothfish and those that did not. Isotopic mixing models indicated that prey groups including large/medium sized toothfish and elephant seal Mirounga leonina pups represented ~60% of the diet relative to prey groups including penguins, baleen whales and coastal fish. These results indicate that toothfish are an important natural prey item of Crozet killer whales and that switching to depredation primarily occurs when fisheries facilitate access to that resource. This study suggests that toothfish, as a commercial species, may also have a key role as prey for top predators in subantarctic ecosystems. Therefore, assessing the extent to which predators use that resource naturally or from fisheries is now needed to improve both fish stock management and species conservation strategies.
Language eng
DOI 10.3354/meps12894
Indigenous content off
Field of Research 0602 Ecology
0608 Zoology
HERDC Research category C1 Refereed article in a scholarly journal
Copyright notice ©2019, The Authors
Persistent URL http://hdl.handle.net/10536/DRO/DU:30120328

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