FILE: A Californian sea lion, Zalophus californianus, Mexico, appears off the Sea of Cortez near Baja California.
© Reinhard DirscherlFILE: A Californian sea lion, Zalophus californianus, Mexico, appears off the Sea of Cortez near Baja California.
A surfer was left shaken on Friday after he was attacked by a sea lion that was presumably infected with a toxic algae that's rapidly spreading across California's coastline.

Ventura County local Rj LaMendola was surfing at Oxnard State Beach on Friday when a sea lion suddenly "erupted from the water" and started barreling toward him, he wrote in a Facebook post.

"Its mouth gaped wide, teeth flashing, and its eyes locked onto me with an unsettling ferocity," LaMendola wrote.

A frenzied struggle ensued between LaMendola and the animal, which began charging at him with its teeth bared and jaws snapping. LaMendola said he dodged the sea lion repeatedly, using his board as a shield while he desperately tried to paddle back to shore in between attacks. By then, he wrote, he "realized this was no playful encounter."

"This was something else entirely — something wrong," he wrote.

At one point, LaMendola swung at the animal to fend it off. The sea lion dodged his punch "with eerie agility," he wrote, before opening its mouth and clamping down on his left buttock. It then shook its head and pulled LaMendola off his surfboard by his flesh.

"I don't know how to describe the fear that gripped me in that moment," LaMendola wrote. "So far from shore, so helpless, staring into the face of this creature that looked like nothing I'd ever seen — its expression was feral, almost demonic, devoid of the curiosity or playfulness I'd always associated with sea lions."

After a harrowing fight, LaMendola said he was able to free himself from the animal's jaws and get back onto his surfboard. He then finally paddled back to shore, the sea lion stalking him and charging at him until his feet hit the sand. He drove straight to the emergency room and is currently recovering from the encounter.

When he contacted the Channel Islands Marine and Wildlife Institute to report the incident, he said he was informed that marine researchers are currently seeing a surge of toxic algal blooms across California's coastline that are known to cause neurological sickness in marine animals like sea lions and dolphins.

The algae, called Pseudo-nitzschia, produces the harmful domoic acid toxin when it blooms. When consumed via forage fish such as sardines, domoic acid can cause larger marine animals to become "dangerous and unpredictable," according to Michael Milstein, a spokesperson for the National Oceanic and Atmospheric Administration.

"Domoic acid can cause animals to act erratically and they can be dangerous when affected by the neurotoxin," Milstein told SFGATE via email.

Milstein said that the first reports of the toxin this year occurred in February, when researchers found it present in the waters near Malibu. Since then, it has spread as far south as San Diego and as far north as San Luis Obispo, and reports have become so numerous that response teams "cannot keep up with them all."

This is the fourth year in a row that a domoic acid event has impacted California's waters, Milstein said. This time around, dolphins appear to be the most impacted, likely because the algal blooms began farther offshore where the animals tend to congregate. Researchers have noticed the animals swimming in circles, Milstein said, and other response teams have reported a surge of stranded marine mammals that have been infected by the toxin.

The number of affected dolphins is approaching at least 100, according to Milstein. Along with sea lions, researchers have also reported pelicans that are suffering from the toxin.

Milstein advised beachgoers to stay a safe distance from marine mammals and to report stranded animals to NOAA's West Coast Marine Mammal Stranding Network.

Following his encounter, LaMendola said that he feels lucky the sea lion only managed to bite his buttock instead of an artery or his face. However, he is still haunted by "the memory of its quivering lips, the relentless pursuit, the feeling of being hunted in a place I've always loved," he wrote.

"The sea lion that attacked me wasn't just acting out — it was sick, its mind warped by this poison coursing through its system," LaMendola wrote. "Knowing that doesn't erase the terror, but it adds a layer of sadness to the fear."