California marine mammals face crisis from toxic algae

A surge of severely ill sea lions and fur seals is washing ashore along the California coast, overwhelming rescue efforts. The Marine Mammal Center in Sausalito reports receiving between 200 and 650 calls daily across its 600-mile territory.

The illness is linked to domoic acid, a toxin produced by algae blooms that thrive in warmer ocean temperatures, such as those caused by El Niño. As algae decomposes, it sinks to the seafloor and is consumed by bottom-dwelling fish. Marine mammals that eat these contaminated fish suffer from severe neurological issues. If not treated quickly with fluids and clean fish, the condition is often fatal.

There are growing concerns regarding the upcoming commercial Dungeness crab season. Because crabs feed on the same algae debris, fishermen fear the toxin may impact harvests. While state officials have not yet detected domoic acid in crabs, formal testing is scheduled to take place just before the season opens in November.