The most significant threat to sea otters is oil spills , to which they are particularly vulnerable , since they rely on their fur to keep warm . When their fur is soaked with oil , it loses its ability to retain air , and the animals can quickly die from hypothermia . The liver , kidneys , and lungs of sea otters also become damaged after they inhale oil or ingest it when grooming . The Exxon Valdez oil spill of 24 March 1989 killed thousands of sea otters in Prince William Sound , and as of 2006 , the lingering oil in the area continues to affect the population . Describing the public sympathy for sea otters that developed from media coverage of the event , a U.S. Fish and Wildlife Service spokesperson wrote : The small geographic ranges of the sea otter populations in California , Washington , and British Columbia mean a single major spill could be catastrophic for that state or province . Prevention of oil spills and preparation to rescue otters if one happens is a major focus for conservation efforts . Increasing the size and range of sea otter populations would also reduce the risk of an oil spill wiping out a population . However , because of the species ' reputation for depleting shellfish resources , advocates for commercial , recreational , and subsistence shellfish harvesting have often opposed allowing the sea otter 's range to increase , and there have even been instances of fishermen and others illegally killing them
Exxon Valdez oil spill
Exxon Valdez oil spill
Sea otter