‘Unprecedented’ toxic algae bloom continues to kill Southern California whales and other wildlife

Southern California could be dealing with its worst toxic algae bloom ever.

Domoic acid toxicosis associated with a bloom off the Southern California coast is responsible for killing brown pelicans, sea lions, and now at least two whales.

The Pacific Marine Mammal Center confirmed Wednesday that a female humpback whale, and a minke whale that was stuck swimming around Long Beach Harbor earlier this month, had high levels of domoic acid in their feces, stomach and urine.

Domoic acid is a potent neurotoxin that affects the brain, nervous system and organs.

Dave Bader, marine biologist with the Marine Mammal Care Center, told LAist rescuers have been receiving thousands of calls about animals that are sick and need help.

“ We have a unprecedented harmful algal bloom off the coast of Los Angeles, actually off the coast of Southern California, right now,” Bader said. “It's the fourth year in a row of a bloom like this …  and then the fact that it's lasted nine, almost 10 weeks, is longer than we've seen in the past.”

Sick animals in SoCal

Brown pelicans suffering from domoic acid toxicity have recently inundated the Wetlands and Wildlife Care Center. The Huntington Beach nonprofit has been caring for hundreds of animals, including dozens of sick pelicans, some of which never recover.

And there’s been no end in sight for SoCal’s marine life. Only about half the animal patients that come into the Marine Mammal Care Center in San Pedro survive, which is lower than previous years.

“We have a lot of animals that are still here and are really very sick, not really recovering in the same way that we've seen in past blooms,” Bader said.

Dolphins, on the other hand, have no chance of recovery.

They’re becoming stranded on local beaches and having seizures right in the surf zone or sand. People have tried to push the dolphins back out to sea, but however well-intentioned, Bader said it’s only causing the animals more stress and potentially leading to drowning.

“We'll give them the dignity of a humane end of life, and one that is reduced in as much stress as possible,” he said. “And the best way to do that is to stay away from the animal and to give us a call so that we can come and respond to it and help that animal pass.”

Sea lions have slightly better odds, but hundreds of the stranded animals have been pregnant. Many of their pups do not survive, and the ones that do are born with neurological issues.

A sick California sea lion with possible domoic acid poisoning is rescued to be evaluated by volunteers on March 25, 2025.

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David Swanson

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AFP via Getty Images

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Two gray whales also stranded in Dockweiler in February and Huntington Beach a few weeks ago. Wildlife officials are waiting for the necropsy results to see if they also had high levels of the neurotoxin, the Pacific Marine Mammal Center said in a statement.

The bigger picture

What’s mostly driving the event is Pseudo-nitzschia, a type of plankton that produces domoic acid. More than a million cells per liter have been found off the Southern California coast, much higher than the 10,000 per liter and above that’s considered a concern. According to the Southern California Coastal Ocean Observing System, it’s the highest concentration ever recorded.

But there are two toxins in the environment right now — domoic acid and saxitoxin.

Officials aren’t exactly sure how the combined toxic blooms are affecting the area, but Bader said climate change is the root cause.

“ It's no longer something that's happening 20 years from now,” he said. “This is happening right now, and we need to do something to mitigate the damage being caused.”

How to help

It’s critical to keep at least 50 feet from sick or stranded animals.

You can help be NOAA’s eyes and ears by reporting marine mammals that are sick, stranded or otherwise need assistance by calling (866) 767-6114.

You can report sick animals to the Marine Mammal Care Center by calling (800) 399-4253, or the California Wildlife Center at (310) 924-7256.

The Marine Mammal Care Center, like other SoCal wildlife facilities, are in need of donations. They budget for about 300 animals a year, but they’ve already surpassed that with the bloom.

“ Our budgets are strained from medicine, food, staffing that are associated with taking care of all of these animals,” Bader said. “So donations are wonderfully helpful to us, especially at this time.”

And the West Coast Marine Mammal Stranding Network hotline is open 24/7.