Unprecedented number of sick and stranded sea lions being found on Los Angeles beaches due to toxic algae bloom

Southern California is grappling with an unusually high number of sick, stranded marine mammals this year, particularly sea lions, as toxic algae blooms spread across the coast. The blooms, which have formed off the shores of Malibu, Dockweiler Beach, and beyond, contain domoic acid—a neurological toxin that’s been wreaking havoc on marine life. These toxic blooms are causing sea lions and elephant seals to suffer from seizures and lethargy, leading them to wash up on the beaches, disoriented and in distress.

The troubling trend is compounded by the fact that this is the fourth consecutive year of such algae blooms, and 2025 is already shaping up to be a devastating year for marine mammals, with rescue organizations expressing deep concern over the growing numbers.

What’s even more concerning this year is the timing and intensity of the algae blooms. In 2023, the Marine Mammal Care Center had 70 sea lions in its care by mid-year. However, by early March of 2025, the center is already operating at nearly half capacity, with over 50 sea lions and other marine mammals under care. The organization can typically accommodate up to 120 animals, and the quick influx of sick animals raises alarms about potential capacity issues.

John Warner, CEO of the Marine Mammal Care Center, noted that the center is now receiving up to eight stranded mammals each day. The timing of this crisis is especially alarming, as it indicates a worsening trend in both the severity and frequency of these algae blooms, which can be directly linked to warmer ocean temperatures and other environmental factors.

The algae blooms are not only affecting the health of individual sea lions but also threatening the broader population. The Channel Islands, a critical breeding ground for nearly 85% of California’s sea lions, are seeing a troubling decline in successful births this year. Many female sea lions, already weakened by the toxic algae, are suffering from miscarriages or aborted pregnancies. The toxins from the blooms are having a devastating effect on their ability to carry their pregnancies to full term.

Warner also expressed concern about the long-term effects of the neurological damage caused by the toxin. While the full impact on sea lion populations is still unclear, it’s evident that the blooms are contributing to a higher mortality rate and potentially fewer successful births on the Channel Islands.

While algae blooms are a natural occurrence, scientists are still trying to understand what is intensifying their frequency and severity. One theory is that environmental factors, such as the ash from the devastating wildfires in Los Angeles and the chemicals used in firefighting, may be contributing to the problem. Warner suggested that the interaction between fire retardant chemicals and the environment could be exacerbating the algae blooms, though this is an area that still requires more research.

As spring and summer approach, more beachgoers will be heading to the coast, which increases the risk of human interaction with these distressed animals. The Marine Mammal Care Center is urging the public to avoid approaching or interacting with stranded animals. Given the neurological effects of the toxins, such interactions could cause further harm or stress, which could be fatal for these already vulnerable animals.

If you come across a stranded sea lion or any other marine mammal on the beach, the Marine Mammal Care Center advises not to touch or disturb the animal. Instead, people should report the sighting to the center by calling 1-800-39-WHALE. With the current situation already reaching critical levels, it’s important for the public to heed these warnings and help protect these endangered species by avoiding unnecessary contact and ensuring that the appropriate rescue teams are notified.