More than 2,000 sickly sea lion pups were left stranded on California beaches in the first three months of this year, researchers said.
The latest numbers released Monday show there were 350 pup strandings in January, 850 in February and 1,050 in March, according to the National Marine Fisheries Service.
In the same period last year, 231 sea lions were left abandoned.
Researchers say dwindling food sources and warmer oceans have led to the strandings, as well as infectious disease outbreaks and harmful algae blooms.
The sick sea lions are typically 7 months old, dehydrated and underweight when they are admitted to rehabilitation centers around the state.
Researchers believe warm ocean temperatures have led to a lack of upwelling, which helps bring colder water and fish to the surface.
Historically, a tropical El Niño weather pattern -- which the National Oceanic and Atmospheric Adminstration declared in early March -- results in an increase in sea lion pup strandings because of physiological stress and changes in available food sources.
The pups' mothers, researchers say, were unable to provide milk supplies, possibly because the mammals traveled further offshore to find food or had difficulty finding food.
Thus, the pups, which are usually dependent on their mothers until 11 months old, prematurely try to feed on their own and end up starving.