Domoic acid poisoning is stranding marine mammals as warnings are issued to beachgoers of the threat posed by animals that are transformed by their illness.

Sea lions and other ocean mammals in Southern California are falling victim to a poisoning event that a local expert calls the worst in recent memory. It is stranding the mammals along the coast as warnings are issued to beachgoers of the threat posed by animals that are transformed by their illness.

At least 20 birds taken to the Wetlands and Wildlife Care Center have died after being poisoned by the domoic acid algae.