Sea Otters at Risk

In 1750, as many as 15,000 several thousand of sea otters lived and foraged along the California coast. Then fur hunters began killing them for their warm, luxurious pelts. By the early 1900s, only about 50 otters along the isolated Big Sur coast had escaped the slaughter. Today’s southern sea otters are descendants of those few survivors.

With conservation efforts, California’s sea otter population has slowly grown to around 3,000. But in recent years, the population has not increased and scientists are trying to understand why.

What threatens sea otters today?

The sea otter population in California remains small and vulnerable, and every otter counts. Parasites, such as intestinal worms, and infectious disease cause more than 40 percent of otter deaths. Protozoal diseases are often fatal to marine mammals, and they appear to be on the rise among wild sea otters, possibly because of higher pathogen and contaminant pollution levels in coastal ocean waters.

The greatest threat to the otter population is an oil spill. Because their numbers are low and they are located in a rather small geographic area, the California otter population could be devastated by oil contamination. Oil ruins the insulating property of an otter’s fur, so many oiled otters die of hypothermia and others die from ingesting the oil or inhaling petroleum fumes. Prevention of oil spills is the best strategy, since rehabilitating oiled otters is quite difficult.