Abstracts
SEARCH Open Science Meeting
October 27, 2003
Seattle, Washington, USA
Polar Marine Mammal Habitat Use May Reflect Climate Change
John L. Bengtson1
1National Marine Mammal Laboratory, Alaska Fisheries Science Center, NOAA, 7600 Sand Point Way NE, Seattle, WA, 98115, USA, Phone 206-526-4016, Fax 206-526-6615, john.bengtson@noaa.gov
Meso-scale oceanic features such as the marginal sea ice zone, hydrographic frontal systems, and biological productivity often correspond to high densities of upper trophic level predators. In the Bering, Chukchi, and Beaufort Seas the distribution and foraging activity of marine mammals reflects the location of such zones. Water column-foraging mammals (e.g., ringed seals, beluga, and bowhead whales) are commonly associated with oceanographic fronts, such as those at the continental shelf-slope boundary and along the marginal ice zone. Benthic-foraging mammals (e.g., bearded seals and gray whales), on the other hand, are likely to be found in areas of high benthic productivity on the continental shelf, presumably related to carbon deposition rates.
Understanding the principal factors that influence the ecological partitioning of these various habitats by marine mammals will improve our ability to detect and predict potential changes in ecosystem dynamics due to climate change or other environmental impacts. In particular, the dramatic thinning of sea ice over the past twenty-five years suggests that large ecological changes can be anticipated in the future for populations associated with sea ice communities.
For example, the extent to which some pinniped species are tied to sea ice habitats throughout the year is known to vary (spotted seals haul out in coastal terrestrial habitats on the Bering Sea’s Russian and Alaskan coasts during summer but it is unknown where ribbon seals go when the Bering Sea is ice free). Similarly, seasonal shifts in sea ice and oceanographic conditions are likely to affect the distributions of both bearded seals, which favor productive benthic foraging zones, as well as ringed seals and beluga whales, which seek aggregations of prey in the water column and under ice. Because of the importance of sea ice in the life history and ecology of these species, they may be particularly vulnerable to climatic change due to warming over the next several decades.
Abstract Categories: Changes in the Sea
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