Two spotted seal populations are safe, one is not. Of the three distinct populations of spotted seals that inhabit the North Pacific Ocean, two total more than 200,000 individuals and are not currently in danger of extinction or likely to become endangered in the foreseeable future, but NOAA’s NMFS is proposing to list a third, smaller population as threatened.
A petition in 2008 by the Center for Biological Diversity to have four types of seals listed under the Endangered Species Act prompted a full status review. The main concern about the conservation status of the species stems from the likelihood that their sea ice habitat has been and will further be modified by global warming and the subsequent loss of sea ice as well as acidification, which may alter prey populations.
NMFS has now completed a comprehensive status review of the spotted seals that determines that the two populations living near Kamchatka and in the Gulf of Anadyr in Russia and in the eastern Bering Sea in United States waters and in both the Sea of Japan and the Sea of Okhotskare safe – both populations count over 100,000 individuals each, the southern population though that is centered in Liaodong Bay, China and Peter the Great Bay, Russia counts only about 3,300 individuals and needs protection.
Spotted seals prefer arctic or sub-arctic waters and are often found within the outer margins of shifting ice floes. During breeding season, spotted seals haul out on ice floes, while during the summer months they can be found in the open ocean or hauled out on shore.
Climate change may alter these three populations’ habitats. Experts expect that large year-to-year fluctuations in sea ice will continue within the Bering and Okhotsk seas, and spotted seals in these two populations may move north in search of suitable habitat in years when the ice is reduced. Also, spotted seals are known to breed and whelp on land when ice conditions are poor. However, such breeding sites are limited and may expose seals to increased hunting and predation.
For the southern population, lower winds and warmer temperatures will likely cause a decline in sea ice large enough to harm the population. Because of its smaller size and vulnerability as a southern species to the potential lack of ice, NOAA decided to list the third population in China and Russia. This means they may be in danger of extinction in the foreseeable future.
The Biological Review Team that conducted the status review was composed of expert marine mammal biologists and climate scientists from NOAA’s Alaska Fisheries Science Center and Pacific Marine Environmental Lab.
The spotted seal (also known as the Largha seal) is a close relative of the harbor seal (Phoca vitulina). Spotted seals are associated with ice during the spring breeding season. From March through May, spotted seals are principally found within the frontal zone of sea ice in the Bering Sea, Sea of Okhotsk, and Japan Sea. The spotted seal’s coat is usually a light-colored background with dark gray and black spots scattered quite densely on the body. Little information is published on the biological characteristics of spotted seal populations. Spotted seals have a lifespan of about 30 – 35 years. They become sexually mature at 3 ‐ 5 years of age, varying over regions and time, and adult females usually give birth every year to a single pup which is nursed for 2 ‐ 4 weeks and then abandoned to fend for itself.
Since the southern spotted seal population segment occurs outside the U.S., no critical habitat can be designated. However, several conservation efforts have been undertaken by foreign nations specifically to protect them.
The four types of seals petitioned to be listed under the Endangered Species Act are ribbon, spotted, bearded and ringed seals. NOAA determined in 2008that ribbon seals should not be listed. Decisions on the bearded and ringed seals are expected next year.
Copyright © 2009 by Marine Science Today, a publication of OceanLines LLC