Sea lions were washing up on the California coast. Specialists suspected that a harmful algae may have been poisoning the marine mammals. 

Beginning in late July, the sea lions had been discovered daily on beaches from Santa Barbara to Ventura. The Channel Islands Marine & Wildlife Institute, a nonprofit dedicated to marine conservation, said the animals were experiencing domoic acid toxicity. Domoic acid is a neurotoxin produced by marine algae called Pseudo-nitzschia australis, according to the CIMWI.

Fish consume the toxic algae and pass the toxins onto sea lions. The toxins cause the sea lions to experience seizures, lethargy, involuntary muscle spasms, and other symptoms. 

Last year, there was a similar outbreak that resulted in the deaths of hundreds of sea lions.