LOS ANGELES – Hundreds of starving sea lion pups are washing up on beaches from San Diego to Santa Barbara, overwhelming rescue centers and leaving scientists scrambling to figure out why.
At island rookeries off the Southern California coast, 45 percent of the pups born in June have died, said Sharon Melin, a wildlife biologist for the National Marine Fisheries Service based in Seattle. Normally, less than one-third of the pups would die.
It’s gotten so bad in the past two weeks that the National Oceanic and Atmospheric Administration declared an “unusual mortality event.” That will allow more scientists to join the search for the cause, Melin said.
Pups are normally weaned from their mothers in April.
Even the pups that are making it are markedly underweight, Melin said.
The most recent pups weighed at the breeding area on San Miguel Island were around 37 pounds, Melin said. They should weigh between 55 and 59 pounds by now, she said.
Melin said she doesn’t know how the pups are making it to the mainland, but they must be using currents and swimming.
“That’s a long way, and they are very small,” she said. “They don’t have a lot of fat, and the water is pretty cold. They are often dehydrated, which is typical with emaciation. It puts them in pretty bad condition.”
Live sea lion strandings are nearly three times higher than the historical average, said Jim Milbury of the National Marine Fisheries Service, part of NOAA.
Between Jan. 1 and March 24, 948 pups were rescued, Milbury said. The bulk of those were in Los Angeles County, which had 395, followed by San Diego, Orange, Santa Barbara and Ventura counties, he said. Last year, only about 100 pups needed saving during the same period.
At the Pacific Marine Mammal Care Center in Laguna Beach, there were 139 animals being cared for Friday. Of those, 131 were sea lion pups, said spokeswoman Melissa Sciacca. She said the center has treated more than 220 sea lion pups so far this year, while the center treated 118 in all of 2012.