Phoebe Beltran sustained several cuts on her right arm and had to be hospitalized after she was attacked by a sea lion in Long Beach.

Experts say frightening encounters with sea lions are becoming more common and the likely reason for recent attacks is a toxic algae bloom poisoning the marine mammals, leading to rare acts of aggression as they move to shallow waters and in closer proximity to beachgoers.

Phoebe Beltran was in the homestretch of her 1,000-yard swim when she suddenly felt an intense pain as the sea lion bit her right arm.

The attack occurred in the area of Ocean Boulevard and Cherry Avenue, in front of the Long Beach Lifeguard Headquarters on 2100 East Ocean Boulevard.

Hundreds of sea lions have died amid a toxic algae bloom, with some animals becoming dangerous and acting erratically.

A common neurotoxin produced by algae blooms is making California sea lions more aggressive. Here’s why it has the power to change behavior—and the danger it poses.

15-year-old Phoebe Beltran has several cuts on her right arm and was hospitalized following the confrontation with the animal on Sunday. Although she has since been released from the hospital and was well enough to return to school, she said the attack has left her shaken up.