Comment from Carleton Ray

Comment on Beringian Ice-dependent Seals G. Carleton Ray, PhD., Research Professor Department of Environmental Sciences University of Virginia, Charlottesville, VA 22903 Tel: 434 924-0551; email cr@virginia.edu Consideration of Beringian (Bering, Chukchi, East Siberian, and Beaufort seas) ice-dependent seals as threatened or endangered is justified by the fact that sea-ice diminishment deprives these species of “critical” reproductive and molting habitat. The species under consideration are: ribbon seal (Histriophoca fasciata), ringed seal (Phoca hispida), spotted seal (Phoca largha), and bearded seal (Erignathus barbatus). I have listed these species in order of their vulnerability, in my opinion, based on knowledge of their natural histories. That is, all of these species share a dependence on annual sea ice as “critical habitat” for reproduction (mating, birthing, nursing) and molt. The total time-period required for these species to fulfill these life-history requirements is in the order of two months, primarily during March through mid-June, depending on location. The case of the ribbon seal is most urgent. Pups are born from late March through mid-April, prefering heavy, snow-covered floes of the loose pack near the southern extremity of sea ice in the Bering Sea. Nursing requires about 4 weeks. The adults then abandon the pups and mate. Pups remain on or near the ice during a 4-week molting period, when they begin to feed. However, during 2006 and 2007, little sea ice remained beyond mid-May, depriving the pups of their habitat and requiring a high-energy demand for aquatic life. It is highly unlikely that the pups could meet this demand, probably resulting is high mortality during the following summer. The ringed seal is widely distributed in suitable sea ice of Beringia and the Arctic Ocean; it is most concentrated in shore ice during reproduction but is widely scatted in continuous ice as well, where it is perhaps more numerous. The spotted seal shares reproductive habitat with the ribbon seal, although its ice preference in the loose pack is somewhat different; it requires a similar period for nursing and molt, but, unlike the ribbon seal, may inhabit coastal shores. The bearded seal is widely distributed in heavy ice of the Bering Sea for reproduction and molt, and is more precocial than the others, swimming soon after birth and taking only about 2 weeks for nursing. Despite these differences, one thing has become abundantly clear, especially during the last decade — that is, the Beringian sea-ice habitat for ice-dependent seals is rapidly changing in persistence and structure, which together determine pup survival. Although southerly sea-ice extent has been impressive in some recent years, so have large areas of open water (polynyas); thus, total ice cover exhibits a dramatic decline. Presently, sea-ice formation occurs 3-4 weeks later and melts 3-4 weeks earlier than 3 decades ago, and this loss is accelerating, as the ice has been thin and subject to melt-freeze cycles. Current projections are that these conditions will continue. Already, it appears that 2008 may repeat 2007, setting another record for sea-ice loss. There is simply no ignoring the almost total loss of habitat for pup ribbon seals during May of 2006 and 2007 and the likelihood of continued sea-ice decline, as well as similar threats to the other three species. I would be pleased to amplify and reference these comments.