Wild Sea Lion Domoic Acid Toxicosis and Rehabilitation

Harmful algal blooms producing domoic acid cause recurring mass poisoning events in California sea lions requiring intensive rehabilitation.

Key Facts

Domoic acid is produced by Pseudo-nitzschia diatoms during harmful algal blooms (HABs) fueled by warm, nutrient-rich waters
Sea lions eating affected fish and squid accumulate high doses causing seizures, disorientation, and brain damage
The Marine Mammal Center in Sausalito treats hundreds of sea lions annually during HAB events
Domoic acid causes hippocampal and limbic brain damage, leaving survivors prone to chronic seizures
Climate change is associated with more frequent and intense HABs along the California coast
Treated animals may be released if neurological damage is limited; severely brain-damaged animals cannot be rehabilitated
HAB monitoring programs allow early warning to fishing communities and wildlife responders

Welfare Considerations

Domoic acid toxicosis causes violent seizures, disorientation, and extreme distress in affected sea lions. Animals found on beaches are often in late stages of intoxication and in severe neurological crisis. The mass casualty nature of HAB events overwhelms rehabilitation capacity, meaning many animals that could be saved die before receiving care.

What You Can Do

Report stranded or distressed sea lions to the Marine Mammal Center or NOAA stranding hotline
Support Marine Mammal Center and similar rehabilitation organizations financially
Advocate for HAB monitoring programs that enable faster response to mass stranding events
Learn about the connection between ocean warming and HAB frequency
Follow ocean health policy to understand how nutrient pollution contributes to HAB conditions