Sea Lions on the Shore: What’s Happening Off California’s Coast?

If you’ve walked along the Ventura coastline lately, you may have noticed something unusual: sea lions—more than usual—lying motionless on the sand, appearing dazed, confused, or worse. While these sleek, charismatic creatures are no strangers to our shores, their recent behavior has sparked concern. And they’re not the only ones. From seabirds to dolphins, ocean animals have increasingly been washing up along the California coast.

So what’s going on?

A Rise in Strandings

Experts say the primary cause is domoic acid poisoning, a neurotoxin produced by naturally occurring harmful algal blooms (HABs). These blooms develop when warm ocean temperatures and excess nutrients fuel the rapid growth of certain algae—especially Pseudo-nitzschia—that release domoic acid. Fish like anchovies and sardines, which are dietary staples for sea lions, absorb the toxin. When sea lions consume these fish in high quantities, they can suffer from severe neurological symptoms.

Signs of poisoning include:

• Disorientation or head weaving

• Seizures

• Physical weakness or paralysis

• Abnormal or aggressive behavior

• In some cases, death

  
  

California’s marine mammal rescue teams have reported record numbers of stranded sea lions in the past year. And the problem isn’t going away—experts warn that warming waters and recurring bloom cycles could make this a seasonal trend.

Public Safety Notice

Most sea lions are docile and prefer to avoid people. But when affected by domoic acid, their behavior can become erratic or aggressive, especially if they feel threatened. There have been recent warnings issued across coastal towns in Southern California, including Ventura, advising residents not to approach or attempt to help any stranded or unusual-looking marine mammals.

If you see a sea lion behaving aggressively or in distress, call the Channel Islands Marine & Wildlife Institute (CIMWI) at 805-567-1505. Do not touch, feed, or try to “help” the animal—it’s both dangerous and illegal under the Marine Mammal Protection Act.

A Reflection of Ocean Health

Sea lions are considered sentinels of ocean health, meaning their condition offers insight into the broader wellbeing of marine ecosystems. The rise in strandings serves as a visible reminder that our coastlines are dynamic, and the ocean’s rhythms are constantly shifting.

What washes up on our shores tells us a story. And right now, that story is calling for attention.

Actions You Can Take

As concerned citizens, we can support sea lions and health marine ecosystems through several straightforward actions:

1. Respect wildlife boundaries: Keep at least 50 feet of distance from all marine mammals.

   
   

2. Report sightings: Help local organizations track and respond to strandings quickly.

   
   

3. Be mindful of runoff: Pick up litter and reduce chemical use that could enter waterways.

   
   

4. Support local conservation groups: Organizations like CIMWI and Channelkeeper play a vital role in monitoring ocean health and educating the community.

   
   

Ventura’s coastline is one of our greatest treasures. By staying informed and respectful, we can help ensure the beach remains a safe, thriving space for both humans and wildlife.

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Sources

National Oceanic and Atmospheric Administration (NOAA). “Harmful Algal Blooms and Marine Mammals.” NOAA Fisheries, 2023, https://www.fisheries.noaa.gov/west-coast/science-data/harmful-algal-blooms-and-marine-mammals. Accessed 10 Apr. 2025.

Channel Islands Marine & Wildlife Institute (CIMWI). “Marine Mammal Stranding Response.” CIMWI, https://www.cimwi.org/. Accessed 10 Apr. 2025.

The Marine Mammal Center. “Domoic Acid and Marine Mammals.” The Marine Mammal Center, https://www.marinemammalcenter.org/animal-care/learn-about-marine-mammals/dominoic-acid. Accessed 10 Apr. 2025.