LAGUNA BEACH – Federal officials said Tuesday they are looking for a suspect who deliberately poured chlorine into a rehabilitation pool for rescued sea lions, leaving 15 of the marine mammals with chemical burns just as they were recuperating from trauma suffered in the wild.

The baffling attack, which occurred either late on April 27 or early the next morning, was the first ever at the renowned Pacific Marine Mammal Center in Laguna Beach, which rescues and takes care of stranded and injured sea animals along the Southern California coastline.

Officials with the National Oceanic and Atmospheric Administration described it as the first animal cruelty case of its kind they have investigated.

The unusual targeting of the sea lions in captivity comes in the wake of record high stranding and mortality along Southern California beaches, an apparent effect of shifts in water tempeartures in the Pacific.

Already this year, the mammal center has rescued a record number of starving and dehydrated animals, well ahead of record rescues in 2013 after NOAA declared an unusual mortality event.

Keith Matassa, director of the center, said his staff became aware of the incident at 6 a.m. on April 28 when they smelled a strong odor of chlorine coming from the outside pool.

Seventeen sea lions within the enclosure were found lying on pavement that surrounds the pool. A white filmy-like substance covered the water.

Fifteen of the 17 animals had significant chemical burns on the surfaces of their eyes. Since the discovery, two center veterinarians have treated the animals around the clock; eight of the sea lions have been medically cleared, while seven others are still in intensive treatment.

Among leads being investigated were images from surveillance video from locations surrounding the marine mammal center. A shadowy figure is visible on the footage, said Laguna Beach Police Sgt. Tim Kleisser.

“We believe someone deliberately brought the chlorine and either poured it into the pool’s filtration system or directly into the water where the sea lions were swimming,” Kleisser said. “We have contacted NOAA whose law enforcement division is working with us. We have several people we are looking at.”

Jim Milbury, a spokesman with the NOAA, said the crime was a violation of the Marine Mammal Protection Act.

Someone behind such an attack could face charges for violating that federal law and state charges of animal cruelty. If the criminal charges are filed, violations could be $20,000 for each injured animal and imprisonment, Milbury said.

Matassa said the injured sea lions were likely rescued in late December or January. Had the attack not occurred, all were scheduled for release back to the ocean last week.

A motive for the attack remained a mystery.

“We really want this person caught,” Matassa said. “It’s just devastating that someone would actually do this. these animals were ready to go back into the ocean. Now they will be in rehabilitation for the next four to six weeks. It’s unfortunate and unfair to have this happen.”

To date, the center has rescued 412 sea lions – the highest number ever. Daily rescues continue and are not expected to slow down anytime soon.

Nearly 3,000 sea lions have been rescued along the Southern Californiua coastline from San Diego to San Francisco. NOAA officials report California sea lion strandings are over 20 times the average stranding level for the same period, based on our records from the last 10 years

Contact the writer: 714-796-2254 or eritchie@ocregister.com or Twitter:@lagunaini