This year, SeaWorld San Diego has beaten its record for sea lion rescues, as the state is heading towards a historic high for sea lion stranding.

The spokesman, Dave Koontz, said that till Monday, SeaWorld rescued 505 marine mammals, including 487 sea lions, and has surpassed its last record of 474 marine mammal rescues in 1983.

In the meantime, the National Marine Fisheries Service has reported that between January 1 and March 8, 1,600 sea lions have washed up on California beaches. It was equal to the total number that stranded in 2013 wherein federal fisheries officials declared an “unusual mortality event” for the species.

The fisheries service has said that of all, 720 are under care at marine mammal centers throughout the state.

According to the National Marine Fisheries Service, there may be a link between the record number of sick and starving sea lion pups and large-scale changes in the Pacific Ocean, which have weakened the food base for marine animals.

Todd Schmitt, senior veterinarian for SeaWorld, said, “The ocean conditions are warmer, so the fish are probably deeper than usual, and the sea lions have to dive deeper and swim further to get more food”.

The 2015 State of the California Current Report was delivered to the Pacific Fishery Management Council last week. The report has mentioned that the climate shifts in the Pacific Ocean have led to warmer waters and less productive ecosystems, with fewer of the tiny cold-water crustaceans that support the ocean food chain.

The report has revealed that the record high surface temperatures, along with shifts in long-term climate patterns and declines in upwelling of cold, deep water have eroded the productivity of the California Current.

A wildlife biologist with NOAA’s National Marine Mammal Laboratory, Alaska Fisheries Science Center in Seattle, Sharon Melin, said that such changes alter the distribution of prey fish, including sardines, anchovy and market squid. As a result of which mother sea lions may have to work harder or spend more time foraging, thus leaving them incapable to nourish their pups.