A study examines how predation risk posed by killer whales alters bowhead whale behavior. Predator intimidation prompts behavioral changes in prey. However, such changes may harm prey, for example, through lost foraging and mating opportunities. To uncover behavioral responses of prey to predation risk in large marine mammals, Cory Matthews and colleagues examined how habitat selection and behavior of bowhead whales changed in response to predation threats from killer whales. Using satellite telemetry, the authors tracked eight bowhead whales and three killer whales in the Canadian Arctic between June and October 2013, including a 3-week period when both species were present in a large, partially ice-covered gulf. Under no threat of predation, bowhead whales preferred ice-free areas in open water. However, when killer whales were present, bowhead whales exhibited reduced activity and moved into areas with dense sea ice and shallow water near shorelines. Bowheads exhibited slow, meandering movements when in open water and fast, directed swimming when close to shorelines; the behavior was reversed when killer whales were present. The findings suggest that predator avoidance in bowhead whales may occur at the expense of foraging in phytoplankton-rich open water, according to the authors.
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Article #19-11761: "Killer whale presence drives bowhead whale selection for sea ice in Arctic seascapes of fear," by Cory J. D. Matthews, Greg A. Breed, Bernard LeBlanc, and Steven H. Ferguson.
MEDIA CONTACT: Cory Matthews, Fisheries and Oceans Canada, Winnipeg, CANADA; tel: 431-999-2679; email: cory.matthews@dfo-mpo.gc.ca
Journal
Proceedings of the National Academy of Sciences