Wayward sea lion may have brain damage from domoic acid

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A sea lion rescued as he tried to cross state Highway 37 in Sonoma County this morning may be suffering from brain damage from exposure to the same neurotoxin that delayed the opening of Dungeness crab season on the California coast this year, Marine Mammal Center officials said.
It's not the first time the wayward sea lion, nicknamed "School Daze" by the center, has been found in odd locations. He was released in late January off the Farallon Islands and biologists hoped he would thrive in the wild, but while he was alert and responsive when he turned up today, he had lost 13 pounds, according to Marine Mammal Center spokeswoman Laura Scherr.
School Daze was spotted on Highway 37 Monday morning near the intersection with state Highway 121 at 9:42 a.m. as he was trying to cross the road, according to the California Highway Patrol
A man got out of his car and chased School Daze down, helping to usher him back to the right shoulder so traffic could resume, but the sea lion kept trying to cross the highway, CHP officials said.
Representatives of the Marin Headlands-based Marine Mammal Center responded to assist and took the sea lion into their care.
They quickly realized they had seen School Daze before and that he had been rescued from odd locations multiple times. His strange behavior leads researchers at the center to conclude he may have neurological damage from domoic acid, Sherr said.
Domoic acid is a potent neurotoxin caused by algae blooms that can accumulate in shellfish and other invertebrates and be transmitted to animals that eat them. The toxin can affect humans as well, and its high presence detected in November prompted the state to the delay the opening of Dungeness crab season.
The toxin can also be transmitted to sea lion pups through their mothers' milk, even weeks after the mother has ingested it, according to a 2014 study by the Marine Mammal Center.
School Daze will get a full examination on Tuesday and an MRI to look for brain damage to see if he might be incapable of returning to the wild.
Sea lion populations in the area have been struggling over the last few years, though it's not clear if domoic acid is the cause. The center has more than 80 sea lions in its care now and has been responding to hundreds of emaciated pups every year.
CHP spokesman Andrew Barclay wasn't sure this morning whether the perplexed pinniped was a sea lion or seal, but said the CHP has previously responded to elephant seals crossing the road there.
"After four years of sea lions in crisis, the initial shock of seeing so many starving sea lions is over and now we're really starting to worry about long-term impacts on the population as a whole," Marine Mammal Center director of veterinary science Shawn Johnson said in a statement.