A toxic algae outbreak is sickening sea lions in California, with a surge in cases reported along the coast as of March 11, 2025. This toxic algae outbreak is sickening sea lions in California at an alarming rate, driven by a neurotoxin called domoic acid produced by the algae Pseudo-nitzschia.

The Marine Mammal Care Center in San Pedro and other rescue facilities are grappling with dozens of affected animals, while experts link the intensifying blooms to climate change and warn of strained resources amid overlapping marine mammal crises.

Over 30 sea lions are under treatment at the Marine Mammal Care Center in San Pedro, with eight admitted on March 5, 2025, alone, signaling a rapid escalation in the past week.

Domoic acid, a neurotoxin from harmful algal blooms, accumulates in prey like sardines and anchovies, poisoning sea lions and other marine mammals. Experts note that blooms have grown more intense and prolonged since 2015, potentially worsened by warming waters and nutrient shifts tied to climate change. Rescue centers face pressure as malnourished elephant seal pups also strand this season, complicating efforts to manage the outbreak.

Escalating Impact on Marine Life

California sea lions are hit hardest, but fur seals, dolphins, and whales are also at risk, with symptoms including seizures, disorientation, and heart failure. Domoic acid attacks the brain and heart, often causing permanent damage if untreated; repeated exposure worsens outcomes.

The Marine Mammal Center first diagnosed domoic acid toxicosis in 1998, with cases rising steadily, peaking during events like the 2023 outbreak that killed hundreds.

The full extent of this bloom remains unclear, but daily admissions of 3-5 sea lions could overwhelm facilities like the MMCC in weeks.

Also Read: Trump’s Foreign Aid Cuts Threaten To Cripple Global Climate Finance, Jeopardizing Vulnerable Nations

Rescue and Treatment Efforts

Veterinarians flush domoic acid from sea lions’ systems with fluids and provide toxin-free fish; anti-seizure drugs like phenobarbital help control symptoms.

The MMCC urges beachgoers to avoid affected sea lions, which can become aggressive post-seizure, and report strandings to the West Coast Marine Mammal Stranding Network at (866) 767-6114.

Recent rescues span Los Angeles, Ventura, and Orange Counties, with Malibu reporting high numbers since late February 2025. Facilities like the California Wildlife Center in Malibu are overloaded, transferring animals to San Pedro, where 17 live sea lions and five deaths were reported by February 27.

Climate Change and Future Risks

Clarissa Anderson from Scripps Institution of Oceanography notes blooms thrive in warmer waters and nutrient-rich upwellings, conditions increasingly common since 2014.

25-30 years of data show blooms are intensifying, possibly due to climate-altered ocean chemistry, impacting ecosystems unpredictably.

Domoic acid can cause amnesic shellfish poisoning in humans via contaminated seafood, though strict monitoring keeps risks low. Federal funding cuts threaten studies on bloom causes and frequency, hindering long-term solutions as outbreaks grow more severe.

Also Read: Denmark Launches Green Transition Alliance India To Strengthen Climate Partnership