About 1,300 sickly sea lions have come ashore in southern California since the beginning of the year and scientists have been scrambling to find out why.

The stranded sea lions are mostly very young pups born last summer. Most of them are typically turning up alive but starving and suffering from malnutrition. Scientists have recorded some weighing less than 20 pounds (9 kg). A year-old sea lion should be well over 50 pounds (22 kg).

Now scientists say they think an odd phenomenon must be harming the creatures' food sources. Nearly 25 percent of the seal pups have died after being brought in for treatment by area biologists.

Since the beginning of the year, 1,293 sea lions have washed ashore from San Diego County to Santa Barbara County. Los Angeles has seen the biggest spike, where 459 strandings have been reported, Sarah Wilkin of the National Oceanic and Atmospheric Administration said Wednesday during a conference call with reporters.

Last month, the National Oceanic and Atmospheric Administration (NOAA) declared an "unusual mortality event" for the pups that allowed more scientists to find funding and time to help search for the cause of this unusual behavior. Researchers are also doing tests to see if pollution, disease outbreak or algae bloom could have an effect.

Young seals are limited as to how far and where they can go to find food. In the case of an odd weather event, such as El Nino, adults would be able to adapt to the changing ocean conditions and search new territory for food. However, young pups are unable to fend for themselves easily and seem to be stranded on the coast.

Authorities are providing adequate nutrition and milk for the pups at local facilities and hoping to release most of the stranded animals back into the ocean. Those animals that are deemed too sickly for the ocean will be placed in zoos or aquariums.