Pursued by fur hunters until nearly extinct, only about 2500 exist along the California coast today, since being protected by a law passed by the California legislature in 1913. Although recovering over some of it's range, this marine mammal faces a variety of threats. A major concern for otters is the threat of a major oil spill along the coastal oil transport routes. Oil fumes at the water surface are very toxic, and oil can also cause illness when it is ingested during grooming and feeding. Many otters died this way when the Exxon Valdez oil tanker ran aground in Alaska in 1989.
Otters are very susceptible to pesticide and chemical contamination.
When these pollutants enter the ocean food chain, they can concentrate in larger predators like the otter. Otters also are threatened by people who unintentionally or intentionally harm them. Boaters sometimes drive through otter habitat and disturb them. Anglers believing the otters to compete for seafood may occasionally shoot them. Dispose of toxic household items properly, not in waterways or storm drains that lead to rivers and the ocean.