Topic editor: Steven G. Gilbert
Lead author: Steven G. Gilbert


  1. #Overview
  2. #References



Sea Lions, whales, dolphins and other marine animals are being affected by Domoic Acid along the California coast from Monterey Bay around San Francisco down to Los Angeles (#Morris, 2007). The toxin is naturally occurring neurotoxin produced during algal blooms, most often from the marine algae genus Psuedonitzschia, which bioaccumulate in shellfish without adverse affects. However, it has serious neurological effects on mammals and it bioaccumulates (#Anderson, 2003). Domoic Acid binds to a glutamate receptor which interrupts the flow of ions across cell membranes (#CIMWI, 2006). This causes violent head weaving and seizures which can lead to brain damage and possibly death (#Anderson, 2003). Since March 1, the Marine Mammal Care Center in Los Angeles have taken in about 70 sea lions suspected of Domoic Acid poisoning and around 35% have died (#Morris, 2007).

The Domoic Acid levels and outbreaks have been rising in the past years and the trend does not look to be slowing. The algea that produces Domoic Acid is most prominent off the California coast - though it also exists in the Gulf of Mexico - and the blooms is triggered by high water temperatures mostly between March and June. With high water temperatures predicted to get even higher as climate change warms the world's oceans, the sea lions, dolphins, and numerous other aquatic animals are threatened Domoic Acid poisoning. Agricultural run-off has also been cited as a cause of some algal blooms (#CIMWI, 2006).

People should not worry about eating contaminated fish due to government monitoring (#Morris, 2007).


Regan Morris. "Sea Lions Hit by High Levels of Acid Poison in California," The New York TImes, June 6, 2007, p. A16.

Melissa Thomas-Anderson, "Domoic Acid Sickens Sea Mammals", The Daily Nexus, May 21, 2003.

Channel Islands Marine and Wildlife Institute (CIMWI), "Domoic Acid Information and History", 2006.