The number of sick sea lions washing up on local beaches has been baffling scientists the past few months. Recently, though, fewer pups have been needing rescue. Scientists say a change in ocean conditions may be the reason for the decrease. Hetty Chang reports from San Pedro for the NBC4 News at 6 p.m. on April 17, 2013.
The epidemic that has so far caused 1,193 ailing sea lion pups to wash ashore in Southern California since January seems to be slowing down, according to marine mammal experts.
Sarah Wilkin, the California marine mammal stranding coordinator for the National Oceanic and Atmospheric Administration, said on Wednesday that the change has occurred in recent days.
"For a couple of months, it was more like ten a day," said Wilkin. "Now we are down to three or four."
The epidemic, which caused NOAA to declare an "unusual mortality event" earlier this month, has baffled scientists.
Now, it appears they've ruled out the possibility that overfishing is depleting the ocean food source, as some have suggested.
"Right now our data does not suggest that any of the stocks off California are overfished," Wilkin said.
Marine biologists are focusing their investigation on environmental factors, such as algae growth, wind pattern changes and sea surface temperature changes, which led to a similar sea lion epidemic during El Niño.
Scientists are also looking into "re-strandings," where the same rescued sea lions are washing ashore again.