At-sea distribution and prey selection of Antarctic petrels and commercial krill fisheries
International audience Commercial fisheries may impact marine ecosystems and affect populations of predatorslike seabirds. In the Southern Ocean, there is an extensive fishery for Antarctic krill Euphausiasuperba that is projected to increase further. Comparing distribution and prey selectionof fish...
Published in: | PLOS ONE |
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Main Authors: | , , , , , , , , , , |
Other Authors: | , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2016
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Subjects: | |
Online Access: | https://hal.science/hal-01386700 https://doi.org/10.1371/journal.pone.0156968 |
Summary: | International audience Commercial fisheries may impact marine ecosystems and affect populations of predatorslike seabirds. In the Southern Ocean, there is an extensive fishery for Antarctic krill Euphausiasuperba that is projected to increase further. Comparing distribution and prey selectionof fishing operations versus predators is needed to predict fishery-related impacts on krilldependentpredators. In this context, it is important to consider not only predators breedingnear the fishing grounds but also the ones breeding far away and that disperse during thenon-breeding season where they may interact with fisheries. In this study, we first quantifiedthe overlap between the distribution of the Antarctic krill fisheries and the distribution of akrill dependent seabird, the Antarctic petrel Thalassoica antarctica, during both the breedingand non-breeding season. We tracked birds from the world biggest Antarctic petrel colony(Svarthamaren, Dronning Maud Land), located >1000 km from the main fishing areas, duringthree consecutive seasons. The overall spatial overlap between krill fisheries and Antarcticpetrels was limited but varied greatly among and within years, and was high in someperiods during the non-breeding season. In a second step, we described the length frequencydistribution of Antarctic krill consumed by Antarctic petrels, and compared thiswith results from fisheries, as well as from diet studies in other krill predators. Krill taken byAntarctic petrels did not differ in size from that taken by trawls or from krill taken by most Antarctickrill predators. Selectivity for specific Antarctic krill stages seems generally low in Antarcticpredators. Overall, our results show that competition between Antarctic petrels andkrill fisheries is currently likely negligible. However, if krill fisheries are to increase in thefuture, competition with the Antarctic petrel may occur, even with birds breeding thousandsof kilometers away. |
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