Dozens of starving sea lion pups have washed ashore in Orange County, the latest calamity to befall marine life and a pattern scientists believe could be tied to El Niño climate conditions.

Since January, the Pacific Marine Mammal Center in Laguna Beach has rescued 27 emaciated sea lion pups that have been stranded on area beaches -- a three- to fourfold increase from the norm, said Dr. Richard Evans, the center’s medical director.

The pups, most under 6 months old, have gone without food for so long they’ve started digesting their blubber and muscle to keep themselves warm in the chilly Pacific waters, biologists say. Their eyes bulge and their skin hangs loosely over protruding spines, hipbones and ribs.

“They’re coming in so severely starved that they look like skeletons,” Evans said.

Only 11 have survived -- well below the center’s typical recovery rate of 80%.

The cause of the starvation is a scarcity of food, mostly anchovies and sardines. Climatologists with the National Marine Fisheries Service say El Niño’s warming effects on Pacific waters is causing fish to flee to colder areas.

“El Niño effects that are in the tropics are finally coming to California,” said Joe Cordero, a wildlife biologist in the agency’s Long Beach office.

Last year, centers along the California coast treated record numbers of malnourished adult sea lions, but this year pups under 6 months are suffering the most, probably because nursing mothers have to choose between feeding their young and surviving.

“If they can’t feed their pups, the ‘selfish gene’ kicks in and they leave them behind,” said Bob DeLong, a research biologist with the National Marine Mammal Laboratory in Seattle.

Sea lions are born by the tens of thousands each summer, fanning out from their main breeding ground in the Channel Islands. But their territory is expansive, stretching from British Columbia to Baja California.

It’s not the first time weather changes have caused young sea lions to starve en masse.

A similar die-off occurred during the last serious El Niño episode in the late 1990s, causing an influx of patients to marine mammal centers up and down the West Coast.

Some experts think El Niño is at least partly to blame for the hundreds of sick pelicans that have inundated Los Angeles-area bird recovery centers in recent months.

In nature, a single stressor is rarely to blame. Last year’s surge in malnourished sea lions was a mystery, but some researchers linked the feeding problems to months of low winds, making for stagnant ocean water with poor nutrients and scant fish populations.

Up the coast, the Marine Mammal Center in Sausalito, the state’s largest treatment facility for sea lions suffering from trauma from Santa Barbara to Mendocino County, last year saw its highest-ever number of malnourished sea lions. Of the 1,366 treated, at least half were pups.

“It was a rough year for sea lions, and it could be another rough one,” said spokesman Jim Oswald. “Anything that affects the ocean environment is going to affect the food chain, and that’s going to affect marine mammals.”

San Pedro’s Marine Mammal Care Center at Ft. MacArthur treated more than 500 marine mammals last year, mostly sea lions. A fair share of them were underweight pups.

So far this year, however, they haven’t had a spike, said staff veterinarian Lauren Palmer.

According to Cordero, who monitors marine mammal health on a regional level, this season’s deaths haven’t yet reached record levels. But that doesn’t mean rescuers aren’t bracing for the possibility of a tough season.

In Laguna Beach, half a dozen sea lions at different stages of recovery stay in heated nursery rooms. It’s a months-long process to nurse them back to health: After a warm bath, caretakers rehydrate the youngsters and tube-feed them with nutrients and pureed squid -- known as “fish smoothies.”

If all goes well, after a month or two, they graduate to gulping down solid sustenance -- squid, anchovies and herring -- exercising in an outdoor pool and practicing competing with peers for food.

Four months later, they’ll be released to the shores where they were found. With any luck, the fattened-up pinnipeds will embark a little better equipped to hunt down that hard-to-come-by fish.

tony.barboza@latimes.com