(Image Credit: IMAGN) A sick sea lion is pictured at the Marine Mammal Care Center in San Pedro, California, on July 6, 2023.
SAUSALITO, CA – A significant increase in marine mammals affected by a neurological toxin from algae has been reported in California, raising concerns of another deadly year for sea lions, seals, dolphins, and whales.
The Marine Mammal Care Center (MMCC) in Sausalito is currently treating over 30 animals suffering from domoic acid poisoning, a neurotoxin produced by an escalating algal bloom off the California coast. Eight animals were admitted on Wednesday alone, highlighting the rapid increase in affected wildlife.
“Since about 2015 we really saw kind of a steep change in how intense these blooms are and how long they last,” said Clarissa Anderson, a biological oceanographer at the Scripps Institution of Oceanography. “They’re definitely longer lasting in general than they were prior to about 2014.”
Domoic acid accumulates in small fish like sardines and anchovies, a primary food source for marine mammals. When ingested in large quantities, it attacks the brain and heart, leading to seizures, heart failure, and potentially permanent brain damage.
Climate change is suspected to be a contributing factor, with rising water temperatures linked to increased domoic acid production. The first diagnosed case of domoic acid toxicosis in California sea lions occurred in 1998, and cases have been on the rise ever since.
“The 25 to 30 years of data we have now is suggesting that something’s changing. They do appear to be getting more intense,” Anderson stated.
The MMCC warns that their resources could become strained if they continue to receive three to five new patients daily. Adding to the challenge, malnourished elephant seal pups are also stranding along Los Angeles county beaches, further straining rescue center capacity.
The MMCC has issued a warning to beachgoers, urging them not to approach stranded marine mammals, as those affected by domoic acid can be especially aggressive.
Researchers are actively studying the algal blooms to better understand their causes and frequency. However, funding challenges threaten these efforts.
Predicting domoic acid events is complex, as it depends on multiple factors, including bloom location, anchovy feeding patterns, and the presence of top predators.
