Top predator to 5-star-diner - Killer whales are feeding at human fisheries more often

Embargoed until: Publicly released: 2022-02-02 11:01

Australia; International; VIC

Photo by Mike Doherty on Unsplash

Killer whales are resorting more often to human fisheries for their meals than previously, according to Aussie and international researchers, who found there were more of these top-predators feeding at fisheries in 2018 than 2003. The team suggest that changes to prey availability caused by human activities has lead to rapid innovations by killer whales to feed on human fisheries, altering the role of this top predator in ocean ecosystems.

Media release

From: The Royal Society

Increasing numbers of killer whale individuals use fisheries as feeding opportunities within subantarctic populations

Biology Letters

Fisheries can generate feeding opportunities for large marine predators in the form of discards or accessible catch on gear. This study assess temporal change in the number of depredating individuals of two killer whale Orcinus orca subantarctic populations (regular and Type-D at Crozet). For both populations, the number of depredating individuals increased during the study period (2003-2018). Increasing abundance is unlikely to account for this due to the poor demographic performances reported for both populations. Rather, the results suggest depredation was acquired by increasing numbers of existing individuals. These findings show how changes in prey availability caused by human activities lead to rapid, yet progressive, innovations in killer whales, likely altering the ecological role of this top-predator in ecosystems.

Journal/
conference: Biology Letters

Research:Paper

Organisation/s: Deakin University

Funder: C.G. was funded by Agence Nationale de la Recherche (Project ORCADEPRED), P.T. and J.A. were funded by the Australian Research Council (Linkage Project no. 160100329).

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