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A sea otter
feeding in Glacier Bay, Alaska photographed by
scientist Jim Bodkin. |
Ironically, it is the otter's fur that brought the animal to the brink of extinction. In 1745, when fur traders advanced from Siberia eastward along the Aleutian Island chain to Alaska's Pacific coast, they were seeking otter pelts for the Asian fur market. At times, they were ruthless in their quest, sometimes forcing Alaska Natives to harvest the mammals. But in many cases, the Native hunters were willing trade partners. The result was drastic: a species that once numbered 300,000 and spread from the Baja Peninsula to the Sea of Japan had, by 1899, dwindled to a few thousand otters in Alaska, a few dozen in California. The rest were gone.
As otters grew ever more scarce, some tried to raise them in captivity. Henry Elliot, writing in the Riverside Guide to Natural History, 1888, noted that "frequent attempts have been made by the Natives to raise them...but they seem so deeply imbued with the fear of man that they invariably die from self-imposed starvation."
No one on the Harriman Alaska Expedition reported seeing a sea otter in 1899, a fact that must have disappointed those scientists interested in the small, sleek mammal. Harriman himself did try to acquire at least one otter pelt. Frederick Dellenbaugh wrote on June 19 that "some Indians, Tlingit, had come along side in a canoe and all three had come aboard leaving a boy to look after the dugout. One had a fine sea otter skin for which he asked four hundred dollars. Mr. Harriman offered him seventy but he would not take it. All the Indians in this region have fixed prices and they rarely deviate from them."
Conservation of the Sea Otter
In July, 1911, the United States, Japan, Russia and Great Britain entered into a treaty "for the protection of fur seals and sea otters in the North Pacific, by outlawing the killing of fur seals and sea otters in these waters by any Americans except Alaska Natives." The U.S. Navy was charged with enforcing the treaty, and, the sea otter in Alaska made a remarkable recovery. Today an estimated 150,000 occupy Alaska waters. In some cases, the local populations rose on their own; in others, otters were relocated in programs carried out by the U.S. Fish and Wildlife Service. Passengers on the Harriman Alaska Expedition Retraced could well see otter groups, called "rafts," resting on the surface in protected bays or inlets along the Alaskan coast. Predators include humans -- otters are one of the subsistence species -- and killer whales. Bald eagles are known to hunt otter pups when other food is scarce.
Biologist Jim Bodkin, who studies the otters in Glacier Bay, says that "the otter is a keystone species, that it is a species that plays a pivotal role in its habitat. Scientists have been able to study the complicated relationship between the otters, kelp and shellfish that exists in the healthy habitats."
Sea otters are the smallest of the marine mammals, but their habits make them relatively easy to study. "They live in shallow water," says Bodkin. "They feed almost exclusively on invertebrates that live on the bottom, urchins, crabs, snails. They dive to the bottom, bring those invertebrates to the surface and consume them there, and we can look at what they're eating. With telescopes we can count the number of prey they bring to the surface, the size of those prey. We can determine how successful they are, how frequently they bring things to the surface."
The sea otter was one of the
many species harmed by the Exxon Valdez oil spill in 1989.
Nearly 1000 otters were found dead in the immediate
aftermath of the spill, and scientists estimate that as many
as 3900 died. An otter's fur, when oiled, loses its
insulating properties; most perished from hypothermia or oil
toxicity. Three hundred oiled otters were caught shortly
after the spill, and were taken for a rehabilitation process
that involved capture, cleaning and a period of recovery in
captivity. The cost of the process was about $80,000 per
animal. Only 200 of these otters survived to be released
into the wild, and monitoring showed that they did poorly.
Since then scientists have speculated that the value of the
rescue process is questionable, and that the truly effective
measures are prevention of any spill and protection of
natural habitats. Such protection would allow otters to
increase and flourish, and, as a species, better withstand
the trauma of an ecological disaster.
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For information on the Harriman Retraced Expedition e-mail: harriman2001@science.smith.edu |