Why are so many baby sea lions dying in California?

LOS ANGELES — Biologists are looking for answers to explain why a huge number of baby sea lions are turning up starving and near death on Southern California's coastlines.

The number of sick and dying sea lions admitted to rescue centers has topped 1,400 so far this year, said Sarah Wilkin, the marine mammal stranding coordinator for the National Oceanic and Atmospheric Administration.

That number is five times the normal amount of sick baby sea lions for this time of year.

"Nobody was quite prepared for the scope of this," said Wilkin. "The major common factor for all these stranded pups is that they're coming in emaciated, dehydrated, basically starving. They have been unable to find enough food to sustain themselves."

Sea lions live on a diet of small fish like anchovies and sardines. Marine biologists are trying to understand what's happening inside the ocean to drive the sea lion pups onto the shore.

Dave Koontz, SeaWorld’s director of communications, said that baby sea lions come inland in search of food when they can't find enough to eat in the ocean.

There might be depleted levels of the type of fish that sea lions eat, or changing water temperatures or currants could be driving the small fish away into different areas. There may also be a disease that has wiped out the bait fish population.

Koontz said it is typical to see some stranded baby sea lions, but that they have rescued an unprecedented number of pups this year.

"As a point of reference, we rescued 131 marine mammals (including sea lions and other marine mammals) in 2012, which is an average year," he said. "This year alone, we’ve rescued more than 350, and of that, about 330 have been sea lions. It’s been an extremely unusual year."

Once rescued, the baby sea lions have a good chance of recovering and being returned to the wild.