Oil Spills and Sea Otters

 
 
 

Over 70 oil spills occur in the United States each year.  One of the most devastating oil spills of recent history is the Exxon Valdez. (Bodkin and Ballachey, 1997)

Oil spills effect sea otters by contaminating their fur and their food.  Oil covered fur becomes matted and can no longer trap air. (Costa and Kooyman, 1982)  Insulation can then decrease 70%. (Davis, et.al,1988)        The sea otter must then compensate for the loss of insulation.  Experiments investigating oiled sea otters show that one way the animals compensate is through peripheral vasocontriction. (Costa and Kooyman, 1982)  Sea otters also have been shown to increase their metabolism through shivering, increased grooming and activity.  In one study of oil contaminated otters, grooming and swimming activities increased 1.7 times.  Sea otters  also increase their food intact because they have relatively little body fat reserves.  Oiled sea otters increased their daily food intact from 20-30% of their body mass to 40-50%. (Davis, et.al,1988)  After an oil spill, contaminated sea otters often cannot maintain that food intake, becoming hypothermic and eventually dying.  (Costa and Kooyman, 1982)

An effective way to decrease the effects of oil contamination is washing a sea otter's coat.  In experiments investigating this, Dawn dishwashing detergent was used to wash the otters' pelts.  Although washing initially decreased the fur's insulating abilities, the fur regained most of its ability after eight to fourteen days of rehabilitation.  (Davis, et.al, 1988 and Costa and Kooyman, 1982)

 

Sea otter being groomed picture courtesy of Jimmy Hu

 

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