• SEARCH Science
• SEARCH Projects
• Resources
• Meetings
• Science Coordination
• International SEARCH
• Contact Information
• Home

Abstracts

SEARCH Open Science Meeting

• Overview
• Agenda
• Presentations
• Abstracts
• Associated Meetings

• Participant List
• Webcast
• Media Coverage
• Student Participation

October 27, 2003
Seattle, Washington, USA

Ringed Seals and Changing Snow Cover on Arctic Sea Ice

Brendan P. Kelly¹, Oriana R. Harding², Mervi Kunnasranta^3
1School of Arts and Sciences, University of Alaska Southeast, 11120 Glacier Highway, Juneau, AK, 99801, USA, Phone 907-465-6510, Fax 907-465-6406, brendan.kelly@uas.alaska.edu
²Biology Program, University of Alaska Southeast, 11120 Glacier Highway, Juneau, AK, 99801, USA, Phone 907-464-6844, oriana.harding@uas.alaska.edu
³Department of Biology, University of Joensuu, P.O. Box 111, Joensuu, 80101, Finland, Phone +358-13-251-453, mervi.kunnasranta@joensuu.fi

Ringed seals (Phoca hispida), the most abundant seal species in the northern hemisphere, depend on subnivean lairs for protection from cold and predators. Newborn ringed seal pups weigh about 4 kg and are especially vulnerable to predation and cold exposure. They are protected from both threats by occupying lairs from birth in April through the first 6 - 8 weeks of their lives. Past anomalous weather events that caused the lairs to collapse or melt before ringed seal pups were weaned led to unusually high predation rates by polar bears, arctic foxes, gulls, and ravens. We recorded air temperatures between -5 and +5 °C in occupied lairs while temperatures (including windchill effect) outside those lairs ranged from -7 to -61 °C. Those ambient temperatures were often well below the lower critical temperature (-25 °C) for the pups, while the temperatures in lairs were consistently well above that limit. We used radio telemetry to monitor the emergence of ringed seals from subnivean lairs in spring 1999, 2000, 2001, 2002, and 2003. At the same time, we monitored weather conditions and snow temperatures at 5 cm depth increments. Abandonment of lairs was associated with the snow pack turning isothermal at which time its thermal and structural integrity was compromised. The snow cover failed especially early in 2002, and by mid-May of that year, all of the seals had abandoned lairs exposing pups prematurely to the threat of predation. Increasingly early snow melts associated with climate change are likely to negatively impact ringed seal populations through increased juvenile mortality.

Abstract Categories: Biological Feedbacks

Back to main abstract page

Previous Abstract | Next Abstract