Red tuna crabs carpet Southern California beaches again

LOS ANGELES (Reuters) -- Masses of tiny red crustaceans known as tuna crabs have washed up for a second straight year along stretches of the Southern California coast in a phenomenon marine scientists say is linked to a rise in ocean temperatures.

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Waves of the dead or dying tuna crabs have been found carpeting the shoreline at various Orange County spots, including Huntington Beach and Newport Beach south of Los Angeles, since the middle of last week.

See more from the scene in the gallery below:

The crabs normally inhabit waters off the Baja Peninsula, in the Gulf of California and the California Current, but warming ocean currents periodically carry the crustaceans farther north and closer to shore, according to scientists.

The latest event and a similar mass stranding of tuna crabs last June along beaches from San Diego to Orange County coincided with the El Niño effect that has increased ocean temperatures in the eastern Pacific.

Also known as pelagic red crabs, the bright salmon-colored creatures resemble small lobsters or crayfish, measuring 1 to 3 inches (2.5-7.6 cm) in length.

Unlike most crabs, they largely spend their lives grazing on phytoplankton as they swim freely in open water rather than crawling along the sea floor, though larger adults will make excursions to the bottom, according to the Scripps Institution of Oceanography in San Diego. Because they live in the water column, the crabs drift with the winds, tides and currents.

Scientists advise the crabs are not safe for human consumption because they may have ingested toxin-producing phytoplankton.

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