A Southern Ocean archipelago enhances feeding opportunities for a krill predator

Lisa-Marie K. Harrison, Kimberly Goetz, Martin J. Cox, Robert Harcourt*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    3 Citations (Scopus)
    4 Downloads (Pure)

    Abstract

    Productivity in the oceans is heightened around oceanographic and bathymetric features such as fronts and islands. This can have a flow-on effect, providing increased food availability for higher trophic level species. Using data from a 5-day combined visual and acoustic survey, we examined the hypothesis that higher Antarctic krill (Euphausia superba) density provides a lucrative resource for humpback whales (Megaptera novaeangliae) at a remote Antarctic feeding area, the Balleny Islands (67oS, 164°E). We assessed whale presence at the feeding area in relation to prey (krill), productivity and environmental variables using density surface modeling. We found stark differences between krill swarms near the islands and those in adjacent open water. Swarms were twice as dense and three times more numerous near the Balleny Islands compared to an open water pelagic environment, suggesting that the islands offered a profitable feeding opportunity. At the feeding area, whales were found in deeper and more productive waters with medium krill densities. These relationships, along with the high krill availability around the islands, may be the result of the Island Mass Effect.

    Original languageEnglish
    Pages (from-to)260-275
    Number of pages16
    JournalMarine Mammal Science
    Volume36
    Issue number1
    Early online date11 Sep 2019
    DOIs
    Publication statusPublished - Jan 2020

    Keywords

    • Antarctic krill
    • density surface model
    • feeding
    • humpback whale
    • island mass effect
    • prey field
    • southern ocean

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