Marine wildlife rescue groups have been responding to an increase in sick sea lions over the past few weeks.
The Channel Islands Marine & Wildlife Institute (CIMWI), which covers Santa Barbara and Ventura counties, says the animals are showing signs of domoic acid toxicosis.
The domoic acid neurotoxin is the result of a naturally-occurring algae. CIMWI explains that filter-feeding animals, including shellfish and small fish like sardines and anchovies, can consume the algae without any ill effects. However, when marine mammals eat the fish and shellfish, it can make them sick.
The toxin targets the central nervous system and brain. Symptoms of domoic acid poisoning in sea lions include lethargy, disorientation, head bobbing and weaving, muscle spasms, seizures, foaming at the mouth, eye bulging, and the inability to move out of the rising tide. Severe cases can result in death.
CIMWI says that while there is no known cure for domoic acid poisoning, depending on the level of illness, symptoms typically subside after 72 hours as the toxin is eliminated from the animal’s body, and affected marine mammals have been known to recover.
Ronnie Glick, Senior Environmental Scientist with California State Parks, says in the Pismo Beach and Oceano areas, they’ve been coming across three to five sick sea lions per day. Lately, they’ve been mostly large adult females.