A surge of sick sea lions are washing up along a popular coast for beachgoers, experts say. Teams rescue affected sea lions, but for many their condition may be too advanced to help.

A wave of mysterious illness is striking marine mammals along California’s coast, leaving sea lions, dolphins, and fur seals disoriented and sick. Experts suspect domoic acid poisoning, caused by harmful algal blooms, as the culprit behind the alarming symptoms. From Oceano Dunes to Santa Barbara, this outbreak has prompted urgent responses from marine wildlife organizations...