Domoic Acid Slams Sea Lions

Drove down to Morro Bay to work with the Marine Mammal Center's San Luis Obispo Operations on Saturday and Sunday, and then drove back Sunday night to work my usual Monday shift at the Monterey Bay Operations facility. In both locations, the rescues that we did appeared to be sea lions with domoic acid symptoms. These were large, older animals, rather than the hundreds of young, emaciated sea lions that we have rescued since May 1st.

While I am no expert, my understanding is that domoic acid is a biotoxin that is produced under certain conditions by agal blooms. Phytoplankton feeders like anchovies and sardines ingest the this biotoxin and, in turn, it is ingested by the sea lions. Domoic acid causes neurological damage, particularly to the hippocampus. The affected sea lions are disoriented and can have seizures. Humans can also have domoic poisoning if they ingest shellfish containing this biotoxin.

My guess is that the effect on the hippocampus is what accounts for the sea lions that wander onto freeways and parking lots. Or like the poor little guy who we found in a Watsonville lettuce field about three miles from the ocean. He died - the farmworkers said he had been wandering around the fields for two or three days and they didn't know who to call. Very, very sad sight.