Sea Otters: Active Trading and Near Extinction – by Merle Blasjo

When the Spanish occupied the west coast of North America, they found large numbers of sea otters in the shoreline waters. These carnivorous marine mammals were found from Baja California to Alaska. Today, these creatures with doll-like faces are a joy to watch for children and adults alike. They can be seen floating on their backs with a rock in paw, cracking open a crab or other shellfish for dinner. Other times an otter can be observed carefully preening, removing foreign material from its thick fur to preserve its insulation properties.


Unlike other sea mammals, sea otters do not have blubber for body temperature control. Instead, they have a remarkably high fur density (up to a million hairs per square inch), which makes an insulation superior to most other animals. This fact led to the development of a robust trading of sea otter pelts and the near extinction of these creature. Spanish traders found a market in Canton, China for these pelts for making luxurious garments and for further trade to Europe. Pelts would bring as much as $2500 (U.S. today equivalent).


Early traders exchanged pelts for quicksilver from Spanish silver mines in South American colonies. Later, as Spain fostered development of missions and ranchos, a need for manufactured items and material arose. Sea otter pelts were a valuable commodity easily accessible to Spanish ships. The indigenous people hunted otters efficiently and contributed to rapid loading of the trading ships. A ship’s hold full of these pelts could be traded for a large bounty of items needed in the developing colonies.


Spain forbade ships of other nations from trading with its colonies, but did not have the means to enforce these laws. Consequently, the United States, Britain and Russia took advantage, risking capture by Spanish armed privateers. Records show that many of these smugglers were successful, contributing to the large numbers of sea otters taken in the nineteenth century.


While the trade provided goods needed for the development of these fledgling communities, the effect on the sea otter population was devastating. From an estimated 150,000 to 300,000 sea otters in the nineteenth century, the number decreased to a few thousand. In 1910 the International Fur Seal Treaty limited the number of sea otters and fur seals that could be taken. This treaty, sponsored by the United States, was ratified by Britain, Japan and Russia.


Sea otter populations increased in the Aleutian islands in Alaska but not in the more southerly regions. Attempts in the 1950s to relocate sea lions to Vancouver Island, Washington and to Oregon did not succeed. Then two federal laws, the Marine Animal protection Act of 1972 and the Endangered Species Act of 1973 placed limits on the taking of Sea otters under some conditions. The previous decline was reversed for several years but soon another major decline occurred.


This decline could no longer be attributed to hunting for fur. Investigators found a number of verified or suspected causes. One was protozoans parasites bred in cats and possums. These parasites found their way into coastal waters from cat litter flushed down toilets or storm drains. Another suspect was diseases from toxic algae blooms which can be generated by fertilizer entering the ocean. Oil, in the form of leaks and spills, can also be damaging to the animals and to their habitat. More than 1000 sea otters perished in the aftermath of the Exon-Valdez oil spill in 1989. And Orcas will eat sea otters when their other food sources were limited.


These situations continue to challenge scientists and Government officials to find mitigation methods so that these remarkable creatures can survive for all time.

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