Toxic algae in the ocean stretching from San Luis Obispo to San Diego has killed dozens of marine animals, prompting environmental groups Thursday to declare the region an extreme danger zone.
The toxic algal bloom produces the neurotoxin domoic acid, which has been detected for the fourth year in a row in Southern California coastal waters.
“It’s the worst we’ve ever seen here in Southern California on many different fronts, but dolphin strandings, it’s unprecedented,” John Warner, the CEO of the Marine Mammal Care Center in Los Angeles, told KABC.
More than 50 dead and dying dolphins have been found along the coast in Los Angeles County this week. In San Diego, 16 were found Sunday.
Debris from the January wildfires and fertilizer runoff may have contributed to the toxic algae’s spread. Small fish eat the algae with domain acid, then marine mammals and birds eat those DA-carrying fish, leading to potentially deadly consequences. Studies have found elevated nutrients offshore after previous major wildfires, NOAA officials said.
Sea lions and birds can be rehabilitated, but DA poisoning is usually fatal for dolphins.
In Long Beach earlier this month, a 24-foot minke whale was swimming in the harbor for several days and officials had tried to push it out to sea, only for it to come back, Milstein said. The whale was then found dead April 3, and necropsy tests showed DA was the cause of death.
According to the National Oceanic and Atmospheric Administration on March 27, the agency’s West Coast Marine Mammal Stranding Network was receiving over 100 reports a day of sea lions and dolphins affected by domain acid. Some animals experience seizures on the beach, or may appear to bob their head, while others like the Minke whale and many dolphins have died.
Officials said beachgoers should remain a safe distance of at least 50 yards from affected animals because they can act erratically when under the influence of the toxin.
In some cases, teams from marine life care centers are bypassing animals with severe domoic acid poisoning and focusing on those that have the greatest chance of recovering.
“We are having to do triage on the beach as we try to identify those animals where we have the greatest chance of making a difference,” Warner said in an NOAA statement, adding that teams responding to strandings have sometimes found dolphins swimming in circles in shallow water near the beach.
Wind-driven upwelling of nutrient-rich, deep-ocean water likely fed the rapid growth of the toxic algae, the NOAA reported. This year’s toxic algal bloom emerged earlier than previous domoic acid outbreaks, and the upwelling may have fueled the algae in deeper offshore waters that dolphins frequent.
A pulse of upwelling in mid-February may have contributed to the toxic algal bloom, according to Andrew Leising, a research scientist at the Southwest Fisheries Science Center. Marine life was first affected around Feb. 20 near Malibu.
More information reporting sick birds, dolphins, whales, sea lions or other marine mammals, visit the West Coast Marine Mammal Stranding Network website.
