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Extreme weather events influence dispersal of naive northern fur seals


Lea, MA and Johnson, D and Ream, R and Sterling, J and Melin, S and Gelatt, T, Extreme weather events influence dispersal of naive northern fur seals, Biology Letters, 5, (2) pp. 252-257. ISSN 1744-9561 (2009) [Refereed Article]

DOI: doi:10.1098/rsbl.2008.0643


Since 1975, northern fur seal (Callorhinus ursinus) numbers at the Pribilof Islands (PI) in the Bering Sea have declined rapidly for unknown reasons. Migratory dispersal and habitat choice may affect first-year survivorship, thereby contributing to this decline. We compared migratory behaviour of 166 naive pups during 2 years from islands with disparate population trends (increasing: Bogoslof and San Miguel Islands; declining: PI), hypothesizing that climatic conditions at weaning may differentially affect dispersal and survival. Atmospheric conditions (Bering Sea) in autumn 2005-2006 were anomalously cold, while 2006-2007 was considerably warmer and less stormy. In 2005, pups departed earlier at all sites, and the majority of PI pups (68-85%) departed within 1 day of Arctic storms and dispersed quickly, travelling southwards through the Aleutian Islands. Tailwinds enabled faster rates of travel than headwinds, a trend not previously shown for marine mammals. Weather effects were less pronounced at Bogoslof Island (approx. 400 km further south), and, at San Miguel Island, (California) departures were more gradual, and only influenced by wind and air pressure in 2005. We suggest that increasingly variable climatic conditions at weaning, particularly timing, frequency and intensity of autumnal storms in the Bering Sea, may alter timing, direction of dispersal and potentially survival of pups. © 2009 The Royal Society.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Behavioural ecology
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Global effects of climate change (excl. Australia, New Zealand, Antarctica and the South Pacific) (excl. social impacts)
UTAS Author:Lea, MA (Associate Professor Mary-Anne Lea)
ID Code:56314
Year Published:2009
Web of Science® Times Cited:40
Deposited By:Zoology
Deposited On:2009-04-21
Last Modified:2012-03-05

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