Congratulations, Southern California. Experts say the worst of the deadly algae bloom is over.
The Marine Mammal Care Center in San Pedro on Wednesday announced that “there have been no new patients showing signs of domoic acid (DA) toxicosis this past week and no signs of Pseudo-nitzschia algae detected in Southern California waters as of Friday.”
In the past few months, animals like birds, sea lions and marine mammals have been sickened or killed by domoic acid poisoning, which is brought on by algae blooms.
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The Channel Islands Marine & Wildlife Institute shared these undated images of sickened sea lions and efforts to help them. -
A sick sea lion, possibly suffering from domoic acid toxicity, is seen resting on a California beach in June 2023. (Channel Islands Marine Wildlife Institute) -
A sick sea lion, possibly suffering from domoic acid toxicity, is seen resting on a California beach in June 2023. (Channel Islands Marine Wildlife Institute) -
Necropsy results revealed that domoic acid toxin was linked to the death of a Huntington Beach humpback whale. (Pacific Marine Mammal Center)
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A dead humpback whale is seen on a beach in Ventura County on April 25, 2025. (KTLA) -
A dead dolphin, likely a victim of domoic acid poisoning, is seen in Ventura County on April 25, 2025. (KTLA) -
A dead dolphin, likely a victim of domoic acid poisoning, is seen in Ventura County on April 25, 2025. (KTLA)
The flood of sickened animals overwhelmed veterinarians and care centers near the Southern California coast, though many of those animals that were treated were able to recover from the potentially fatal toxin.
“This was the longest, most toxic, and deadliest bloom we’ve ever experienced,” the MMCC said. “Because of your support and advocacy, we got through it, and hundreds of marine mammals received a second chance at life!”
Though the worst of this crisis appears to be over, the MMCC is preparing for the next battle by expanding its facilities and increasing patient capacity.
As LAist notes, climate change is making oceans more acidic as they absorb more carbon dioxide, conditions that allow many algae to thrive.
“And some of those algae, like Pseudo-nitzschia, produce the toxic domoic acid,” LAist explains.
“We’re seeing these types of events happening year after year after year. And they’re increasing in their intensity and their frequency,” David Bader, a marine biologist with the MMCC, told LAist.
As a result, the MMCC is currently fundraising to assist in that preparation effort.
“We couldn’t have made it through without your support,” the organization added. “Thank you for every donation, comment, and share. Here’s a big California sea lion-sized thank you from all of us at MMCC!”
