Crabs may portend a big El Niño
Usually seen in warm Mexican waters, pelagic red crabs have appeared off Santa Barbara.
Researchers may have found another telltale sign that the strengthening El Niño will be Godzilla-like.
On an Aug. 15 trip, sea lion biologist Jeff Harris filmed tens of thousands of tiny red crabs in the ocean at Point Bennett off San Miguel Island in Santa Barbara County. As he sat in a raft and paddled through the warm water, Harris shot video of the creatures bobbing in kelp and interacting with a northern fur seal.
More surprising was that these types of crustaceans, pelagic red crabs (pleu-roncodes planipes), are usually found in Mexico’s warm waters, said Harris, who works for the National Marine Mammal Laboratory.
But as sea temperatures increase, the crabs follow the pockets of warm water and move north.
“They will do all right until they hit cold water, and then they will strand on the beaches,” Harris said. “This is definitely associated with El Niño.”
That explains why millions of the tiny crabs have been recently washing ashore on miles of coastline from Orange to San Diego counties, attracting hundreds of onlookers, he said.
Once the ocean water sweeps the critters to shore, they die.
While researching sea lions for two months on San Miguel, one of the eight Channel Islands, Harris noticed the crabs were marooning more than once a week.
“This is very important because the water is already very warm, and it is said that the El Niño is still on its way,” he said. “This could be a record event.”
It’s also bad news for California sea lions and northern fur seals.
Pups are starving in the Channel Islands as their mothers find it difficult to find food in the unusually warm water, according to the National Oceanic and Atmospheric Administration.
Their staples, including sardines and anchovies, have gone north in search of cooler water. This leaves the pups frail, emaciated and exhausted, and many have been stranded along the California coast.
During El Niño, the tiny crabs are occasionally found in the sea lion diet, Harris said. But they aren’t a staple for the animals in the Channel Islands. California sea lions don’t usually consume crabs.
“I think they might not offer much nutritional value, or it is just that they are unaccustomed to foraging on a crustacean,” he said.
The National Weather Service’s Climate Prediction Center said computer models are predicting a strong El Niño to peak in late fall or early winter. At this time, this year’s El Niño appears to be stronger than it was at this time of year in 1997, when the most powerful one on record formed.