Toxic Algal Bloom Fuels Marine Mammal Crisis Along California Coast

Over 140 sea lions and 50 dolphins have been affected, with aggressive behavior raising public safety concerns as rescue centers struggle to cope.

A harmful algal bloom producing domoic acid is causing severe illness and death among marine mammals off Southern California's coast.
Marine rescue centers have treated over 140 sea lions and nearly 50 dolphins since February 2025, with experts warning this event may surpass the severity of the 2023 bloom that killed 1,000 sea lions.
Affected sea lions exhibit neurological symptoms such as seizures, lethargy, and aggression, with one aggressive sea lion recently attacking a surfer in Ventura County.
Climate change and pollution are intensifying the frequency and severity of harmful algal blooms, according to experts and environmental organizations.
Public safety warnings have been issued, urging people to avoid approaching sick or aggressive sea lions, as rescue efforts remain overwhelmed.