Dave Bader said a powerful El Niño forecast for this winter could push El Niño California Sea Levels into a pattern that brings malnourished pups onto Southern California beaches. The Marine Mammal Care Center is watching the season after seeing how similar conditions once drove mass strandings.
Violet, a wrinkled northern elephant seal pup, slid out of a crate and onto San Pedro’s Cabrillo Beach in late August before lumbering into the surf. She was one of the 250 to 500 patients the Marine Mammal Care Center rescues along the Los Angeles County coast every year, a workload that could grow if food conditions worsen for young animals.
Dave Bader and the Marine Mammal Care Center
“We can look at the past as the best predictor for the future,” Bader said, pointing to the last time El Niño-like conditions paired with the ocean heat wave known as the Blob. From 2013 to 2016, thousands upon thousands of California sea lion pups were found underfed and in distress during that stretch.
“When we’ve seen conditions like this, the major effect for Southern California has been mass stranding of malnourished pups,” Bader said. He described the seasonal food chain in simple terms: “You get a bonanza of life” when upwelling is strong in spring and summer, but young animals have less room to adapt when it weakens.
Southern California and the West Coast
El Niño and marine heat waves can change the timing or force of winds and potentially dampen upwelling, which normally brings deep, cold, nutrient-rich water to the surface on the West Coast. Bader said adults can usually cope better with those shifts: “Adult animals can usually figure it out.”
“They can swim further. They can go out to find where the food is,” he said. “The young animals just don’t have that same physiological capacity, perhaps, or just not the long-term knowledge that a more seasoned adult animal would have.” He added: “So they end up stranding in droves.”
Monterey County to Sonoma County
The south coast fear is about malnourished pups, but the north coast problem already visible is domoic acid poisoning rather than starvation. Dozens of sea lions suffering from that poisoning have turned up on beaches from Monterey County to Sonoma County in recent weeks, and warm waters from an El Niño event can fuel toxic algae blooms in those areas.
For Southern California, the hard part is timing. The effects of the El Niño and marine heat wave might not appear until winter, spring or even later, leaving the Marine Mammal Care Center to prepare before the first wave of sick young animals arrives.
