Red Crabs Invade San Diego Shores

Tuna crabs wash ashore by the thousands

Massive numbers of bright red tuna crabs have washed up on San Diego beaches over the past several weeks. Pleuroncodes planipes (also known as tuna crab or pelagic red crab), have been seen in droves along the San Diego coastline, from Ocean Beach to La Jolla. 

“Typically such strandings of these species in large numbers are due to warm water intrusions,” said Linsey Sala, collection manager for the Pelagic Invertebrates Collection at Scripps Institution of Oceanography, UC San Diego. "Because of the long sampling history of the CalCOFI (California Cooperative Oceanic Fisheries Investigations) program, unusual events such as these can be compared and evaluated in context with other events in the program’s 66-year history.”

Tuna crabs primarily inhabit the west coast of Baja California, Gulf of California, and the California Current. The species is unique in that it can live its entire life cycle in the water column (surface to seafloor), from larvae to adulthood. Larger adult tuna crabs are known to inhabit the epibenthos (just above the seafloor), and make vertical excursions to the surface to feed on phytoplankton. Because they live in the water column, they are subject to the winds, tides, and currents.

Due to unknown toxins that may be present within the crabs, human consumption is not recommended.

• For more natural history information on tuna crabs, see the Zooplankton of San Diego Region website entry for this species: https://scripps.ucsd.edu/zooplanktonguide/species/pleuroncodes-planipes

• Related Image Gallery: Red crabs Invade San Diego

 

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Scripps Institution of Oceanography at the University of California San Diego is one of the world’s most important centers for global earth science research and education. In its second century of discovery, Scripps scientists work to understand and protect the planet, and investigate our oceans, Earth, and atmosphere to find solutions to our greatest environmental challenges. Scripps offers unparalleled education and training for the next generation of scientific and environmental leaders through its undergraduate, master’s and doctoral programs. The institution also operates a fleet of four oceanographic research vessels, and is home to Birch Aquarium at Scripps, the public exploration center that welcomes 500,000 visitors each year.

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