Mystery as dozens of dead sea lions wash up on the coast between Newport and Laguna Beach

They started washing ashore in February. As of last week, 21 dead sea lions — including six in one day — were reported to Laguna’s Pacific Marine Mammal Center. Their bellies filled with fish, the animals didn’t fit the pattern of marine mammals that get rescued at this time of year – which are very thin, young pups that haven’t learned to hunt yet. With a little bit of help from rescue teams, those pups generally learn to hunt and are released to the wild pretty quickly. 

But these dead animals are older, healthy looking, with stomachs filled with squid. Necropsies are being performed and tissue samples taken. It’s too early for sea lions to be getting sick from high domoic acid. That tends to happen during late spring and early summer months, when unusually high temperatures cause toxic algal blooms. What’s more, the ailment tends to affect females. These dead sea lions are males.  


Dr. Alissa Deming, VP of Conservation Medicine and Science at the Center says they did receive one female, with domoic acid toxic seizures, in February, during a brief heat wave. They rescued, saved and released "Candle" as they called her, but that’s the only one so far. 

"It’s way early for toxic algae blooms, which we monitor," Deming said. "We are testing tissue samples of the dead animals for everything we can think of." 

We asked if the recent oil spill from a broken pipeline off our coast could be the cause.  Dr. Deming explains that it has been a while since that spill, and the animals they treated right after the spill did not show severe damage from the oil. But, "again, we are testing for all options," she said. One possibility is that the group of male sea lions (which tend to hang out in groups) all fed on something that was toxic. The question is what, and why?

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For now, they are asking ocean users to keep their eyes out for sick looking or dead animals. Don’t touch or corral the live ones, but immediately call the center's Hot Line at 949-494-3050. Take some pictures to send them. 

For the many scuba divers in popular spots like Heisler Park, video of sea lions acting strangely, underwater, could be helpful. Don’t get too close, or get hurt, but if you happen to catch video of animals that look like they're having seizures, send it to them.

More information about the center and what they do can be found on their website,

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