Sea lion rescuers swamped

People in Marina del Rey, Calif., were surprised when a sea lion pup wandered into their apartment complex.

They named him Walter.

But getting help for Walter when he was spotted last week wasn't easy. He's just one sick pup among many ailing sea lions overwhelming marine mammal centers in California. Nearly 1,000 have washed ashore so far this year.

Emaciated and dehydrated sea lions, mostly pups about 8 months old, have been admitted in record numbers to facilities along the coast. It's the third straight year of record strandings in the state.

According to National Oceanic and Atmospheric Administration Fisheries, 550 sea lions were being treated statewide as of Feb. 18.

Rescuers are swamped.

Peter Wallerstein of Marine Animal Rescue works in much of Los Angeles County. He said he received calls about Walter before the young sea lion wandered into the complex. But as long as the pup was out of the way of people, he was on the back burner for rescue.

"But then this lady called me and said he was up in the parking lot. So I responded immediately because I knew it would be bad for him," Wallerstein said.

"There are so many strandings right now we cannot possibly pick up all the pups," he said.

Wallerstein's two-person rescue team receives two dozen or more calls a day. He said he has been rescuing marine mammals for 29 years and "for January and February, it's the highest number of rescues I've ever seen."

This month, researchers from NOAA's National Marine Mammal Laboratory visited sea lion rookeries on the Channel Islands, where most of America's sea lions breed, in a search for clues to the strandings.

They measured and weighed pups and found them to be considerably underweight, with an average growth rate that was the lowest they had seen since they began monitoring in the early 1990s.

The pups' weight was similar to that in 2013, the year of an "unusual mortality event" for sea lions, a phenomenon characterized by an unexpected number of strandings and significant die-off of a marine mammal population. In 2013, the Marine Mammal Care Center in San Pedro was treating two to three times as many California sea lions as usual. David Bard, operations director, said that in the first two months of this year, the numbers are double what they were at the beginning of 2013.

Wallerstein remembers doing 25 rescues in the first two months of 2013. So far this year, he has rescued 117 marine mammals.

Scientists are awaiting more data from the research on the Channel Islands, but NOAA Fisheries said higher-than-average sea surface temperatures along the California coast in fall 2014 may be a factor in the strandings.

Another possibility is "the sea lion population is reaching carrying capacity," Bard said.

Still, "the current stranding crisis is concerning because it indicates a more complex occurrence in the ocean," the center said in a statement. "Our ocean is clearly under stress."