In what seemed like a repeat of history, a number of sea lions and seals stranded in the coasts of California have been recorded early this year, but this time their numbers rose steeply. Scientists conclude that this is caused by a dearth in food supply.
From the 291 stranded marine mammals recorded last year, the numbers went up to 446 this year, according to the Marine Mammal Center in Sausalito, even beating the highest record of stranded seals, sea lions and elephant lions in 1998 with 388.
"The ones we are seeing are basically starving to death," said Shawn Johnson, director of veterinary sciences at the center. "It's definitely a mystery. We're hoping it's not the new norm."
Most of the stranded seals are dehydrated and starving pups, thought to be deserted by their mothers either because they are off in search for food or they have nothing to feed to their offspring.
One of the pups included "Hoppie," a sea lion that was found last March limping across a Modesto almond orchard, which is almost a mile from the San Joaquin River in Central California. It was sore and was famished and dehydrated due to the long trip it underwent. On Tuesday, after spending weeks of recuperating in the center, Hoppie was released along with two other sea lions named Eugene and Fenimore by the center's volunteers.
Experts have also speculated on the angle of a toxic algae flourishing in Monterey Bay that has killed sea birds in the area.
However, recent findings from the National Oceanic and Atmospheric Administration (NOAA) revealed that the main cause of the seals getting stranded is simply because of the lack of food supply, particularly the seals' favorite prey-the sardines.
"A single epidemic or infectious cause was not found," said fishery biologist Sarah Wilkin of NOAA's marine mammal health and stranding response program. "There was a failure in nursing of some of the mothers to pups, and we still don't understand exactly why."
The dwindling number of sardines has affected fishermen in the area as well, NOAA reported. Last December, the number of metric tons for the hauled sardines was decreased to 5,446 metric tons from 18,073 metric tons to avoid over-fishing.
Wilkins said it may be because the Pacific sardines went further from the coasts for spawning in the last two years, hence making food hunting a more difficult task for the young sea lions and seals.