
Toxic Algal Bloom Turns California Sea Lions Aggressive
California, April 2025: A disturbing wave of aggression by sea lions along California’s coast has left beachgoers alarmed. The animals, usually playful and calm, have begun attacking humans a behaviour scientists describe as both unprecedented and “demonic”.
At the heart of this troubling transformation is a toxic algal bloom off the southern Californian coast. The algae, Pseudo-nitzschia, produces domoic acid, a potent neurotoxin that has infiltrated the marine food chain. Small fish consume the algae, and larger predators like sea lions feed on them, unknowingly ingesting the toxin.
The result has been devastating: hundreds of sea lions lying sick along the coast, suffering from muscle spasms, confusion, and extreme aggression. Some have bitten surfers and beach visitors. While no ...