It's a red coastline in Southern California as hundreds of thousands of red tuna crabs invade beaches, brought to the region by warm ocean currents, officials said Wednesday.

The tiny crustaceans have been dying en masse on beaches from San Diego to Orange County, although some have been washed back out to sea alive, Reuters reports.

"It looked like a red carpet - a good foot-to-16 inches thick," local resident Johnny Fotsch described to CBS News. "It kinda took me back a little because I never seen anything like this before.

Red tuna crabs - or pelagic red crabs - are native to the waters of Baja California, but scientists believe unusually warm ocean currents are washing them further north and closer to shore than usual.

"They are mostly grazers in the upper 200 meters (yards) of the ocean," noted Linsey Sala, collection manager at the University of California, San Diego's Scripps Institution of Oceanography. "Because they can swim in the water column, they can be transported by strong currents."

However, despite these strandings, Sala and other experts say that the plankton-eating crabs are not necessarily in danger. In fact, this trend has happened before. The last time was in 1997, right before a massive El Niño occurred - a warming of Pacific waters that causes changes in the atmosphere.

"This is definitely a warm-water indicator," Sala told Reuters. "Whether it's directly related to El Nino or other oceanographic conditions is not certain."

Scientists have also considered that toxic-producing phytoplankton may be to blame. Currently, there is a toxic algae bloom in the Pacific Ocean stretching from North California to Washington State - possibly the largest ever detected off the US West Coast. The crabs may have ingested the phytoplankton responsible for this bloom, explaining for the strandings.

It remains to be seen what exactly is responsible for this crab invasion and how long it will last, but maybe soon the tides will turn.

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