Toxic Algae Outbreaks Off US West Coast Set to Worsen With El Niño
A harmful algae bloom off California is thought to be poisoning dolphins and sea lions. El Niño may make such events more common—but not everywhere in the US.
Dead fish float in the waters of Lake Merritt in Oakland, California, as a result of a toxic algae bloom in 2022.
Photographer: Justin Sullivan/Getty ImagesSea lions and dolphins have been washing up sick or dead on Southern California beaches, poisoned by eating fish containing a dangerous neurotoxin. It’s the result of a harmful algae bloom, a natural phenomenon that turns water blue, bright green, brown or red, and occurs mostly in the summer and fall.
Algae blooms have been supercharged in recent years by agricultural pollution and global warming (the algae prefer warmer water). The returning climate pattern known as El Niño raises the likelihood of toxic algae outbreaks on the US West Coast and may do the same in Florida, though its influence there is not as clear cut.