Alaska is the heartland of the sea otter 's range . In 1973 , the population in Alaska was estimated at between 100,000 and 125,000 animals . By 2006 , though , the Alaska population had fallen to an estimated 73,000 animals . A massive decline in sea otter populations in the Aleutian Islands accounts for most of the change ; the cause of this decline is not known , although orca predation is suspected . The sea otter population in Prince William Sound was also hit hard by the Exxon Valdez oil spill , which killed thousands of sea otters in 1989
Exxon Valdez oil spill
Exxon Valdez oil spill
Sea otter