Scientists Find Swarming Red Crabs on Seafloor

Posted on April 12, 2016

Crab swarm at Hannibal Bank Seamount

Scientists found thousands of red crabs (Pleuroncodes planipes) swarming on the seafloor. The crabs were spotted by researchers aboard the manned M/V Alucias's RV2 submarine during an expedition at the Hannibal Bank Seamount off the coast of Panama. The seamount is an ecological hotspot in the coastal eastern tropical Pacific Ocean off Panama.

Jesús Pineda, a biologist at Woods Hole Oceanographic Institution (WHOI) and chief scientist on the expedition, says the crab swarming discovery was mesmerizing. A turbid layer on the seafloor turned out to be thousands of swarming crabs.

Pineda says, "When we dove down in the submarine, we noticed the water became murkier as we got closer to the bottom. There was this turbid layer, and you couldn't see a thing beyond it. We just saw this cloud but had no idea what was causing it. As we slowly moved down to the bottom of the seafloor, all of the sudden we saw these things. At first, we thought they were biogenic rocks or structures. Once we saw them moving-swarming like insects-we couldn't believe it."

The swarming crabs can be seen around the 1:10 mark. Take a look:

A research paper on the swarming crabs was published here in the journal, PeerJ.

Photo: Jesús Pineda, Yogesh Girdhar, Woods Hole Oceanographic Institution

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