Updated Jun 27, 2023 - Science

"Unprecedented" number of sick sea lions washing up on California beaches

A seal on a beach in California.

A sea lion on a beach near the Marine Mammal Care Center in San Pedro, California. Photo: Los Angeles Unified School District

Hundreds of sea lions and dolphins are washing up dead or sick on California beaches due to a toxic offshore algae blooms, officials warn.

Driving the news: The Marine Mammal Care Center, which serves Los Angeles County, is at full capacity as the nonprofit rescue organization responds to "an unprecedented number of animals" falling ill to a neurotoxin from the bloom, CEO John Warner said at a news conference Tuesday.

State of play: The National Oceanic and Atmospheric Administration reports there were more than 1,000 reports of sick and dead marine mammals from June 8 through June 14.

  • The Channel Islands Marine & Wildlife Institute, which serves Santa Barbara and Ventura counties, estimates it's responded to 250 to 350 reports per day of animals affected by domoic acid, a naturally occurring toxin that certain types of algae produce that can kill animals and even humans if consumed in high quantities.
  • "What makes the situation unique" is that many of the animals are washing up on popular beaches, like Venice Beach and at Santa Monica Pier, "and they're seizing, foaming at the mouth or completely unresponsive ... thrashed around in the water line," Warner said. "That's something people don't see on a regular basis."
  • Wildlife teams began to see high numbers of sea lions with demoic acid in the first week of June following "a large stranding event in Santa Barbara in Central California and within two weeks our hospital here was at maximum capacity," per Warner.

Zoom out: Naturally occurring harmful algal bloom (HAB) events are nothing new.

  • However, “the levels of concentration are greater than they ever have been because of warming ocean temperatures — this is all climate change-related — the runoff from our rivers and agricultural fertilizers into the water creates a perfect storm for these events to continue to get bigger and bigger and more severe," Warner said.
  • The Los Angeles Unified School District announced Tuesday it's helping the Marine Mammal Care Center with a temporary outdoor space at a local school that'll enable wildlife teams to help 20 sick sea lions at a time.
  • In terms of marine mammal strandings, this has been the "most significant HAB event" in the past decade, said Justin Viezbicke, NOAA's California stranding coordinator, in an emailed statement.

Between the lines: "The frequency and severity of harmful algal bloom events along Southern California's coast has been increasing in recent decades," per the Channel Islands Marine & Wildlife Institute.

  • "Climate change and rise of nutrient pollution are environmental circumstances that are potentially causing HABs to occur more often and in locations not previously affected," according to the institute.
  • "El Niño brings warm water conditions that can promote higher toxic algae blooms."

The bottom line, via Warner: "Everyone assumes this is going to be a new norm, not a one-off."

In photos: Race to save California's sick sea lions

Sea lions and their pups are recovering from deadly algal bloom at the Marine Mammal Care Center (MMCC) in San Pedro on Tuesday, June 27.
Sea lions and their pups are recovering from deadly algae blooms at the Marine Mammal Care Center in San Pedro, California, on June 27. Photo: Brittany Murray/MediaNews Group/Long Beach Press-Telegram via Getty Images
 Sea lions are recovering from deadly algal bloom at the Marine Mammal Care Center (MMCC) in San Pedro on Tuesday, June 27, 2023.
Several of the sea lions in recovery at the Marine Mammal Care Center in San Pedro, California, on June 27. Photo: Brittany Murray/MediaNews Group/Long Beach Press-Telegram via Getty Images
 Sea lions are recovering from deadly algal bloom at the Marine Mammal Care Center (MMCC) in San Pedro on Tuesday, June 27, 2023.
The Marine Mammal Care Center in San Pedro, California, is helping sea lions recover from deadly algae blooms. Photo: Brittany Murray/MediaNews Group/Long Beach Press-Telegram via Getty Images
Rescue team members unloads a California Sea Lion named Lainey from a truck at the Pacific Marine Mammal Center in Laguna Beach after it was found in Laguna Beach having seizures from toxic algae blooms Tuesday, June 20, 2023. The toxic algae bloom along the coast is killing dolphins and sea lions. More than 1,000 marine mammals along the Southern California coast have gotten sick or died due to the bloom of toxic algae, due to high concentrations of domoic acid a neurotoxin produced by the marine algae Pseudo-nitzschia
Rescue team members unload a California sea lion named Lainey from a truck at the Pacific Marine Mammal Center in Laguna Beach after it was found on Laguna Beach having seizures from toxic algae blooms on June 20. Photo: Allen J. Schaben/Los Angeles Times via Getty Images
Veterinarian Alissa Deming, left, and veterinarian assistant Malena Berndt give anti-seizure medicine to a California sea lion named Patsy in a recovery room at the Pacific Marine Mammal Center in Laguna Beach after it was found on Huntington Beach having seizures from toxic algae blooms on June 20. Photo: Allen J. Schaben/Los Angeles Times via Getty Images

Editor's note: This article has been updated with more photos.

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