A 7-foot long dead dolphin washed up dead in Shaw's Cove on Tuesday afternoon, according to Laguna Beach police.
The Pacific Marine Mammal Center identified it as an adult female bottlenose dolphin.
A lifeguard reported that a dolphin was "not looking right" in the water, according to Marine Safety.
He noticed that dolphin made a 180-degree turn when it got near the rocks and saw it kick.
The Pacific Marine Mammal Center was notified of a potential rescue. Less than 10 minutes after the call, he said the dolphin changed to a belly-up position in the water. A few moments later it washed ashore.
The center responded immediately to the call about 12:30 p.m., so the dolphin was not in the cove for very long, said Director of Animal Care Michele Hunter.
The dolphin was dead when center officials arrived.
It had a significant amount of abscesses, necrotic tissue and was in "pretty bad shape," according to the center.
The Los Angeles County Museum is conducting a full necropsy, Hunter said.