Federal researchers just returned from a survey of a major Southern California sea lion rookery and they saw signs that the marine mammals are already struggling.
Scientists go to San Miguel Island each fall to gauge the health of the sea lion population. The island is located off the coast of Santa Barbara.
The latest survey of sea lions revealed many pups on the island are significantly underweight.
"The pup weights were the lowest recorded in 41 years. And the average weight of female pups was about 11.8 kilograms," said Sharon Melin, a federal research biologist with the National Oceanographic and Atmospheric Administration.
That weight is more than 30 percent below what's considered normal.
Marine mammal rescue officials said they are bracing for the possibility they'll be dealing with a record number of rescues in 2016. This year was a record year for rescues.
One culprit may be warmer than normal ocean waters which may be affecting the food supply sea lions rely on.
"The tropical El Niño has done this repeatedly, through history, and it's going to continue to do that," said Nate Mantua, a climatologist at the Southwest Marine Fisheries Center. "And we have other things that happen like this warm blob which in many ways is unlike the El Niño effect, but its another part of the natural variability."
Mantua said there's a chance warmer water could become a permanent part of the Southern California ocean environment. If that happens it could be devastating to the sea lion population.
Sea lions have experienced difficult conditions for five of the past seven years, but the population level remains at record levels. Scientists estimate there are 300,000 sea lions living in the region.
