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Massive Crab Swarm at Ocean Floor Filmed

Video taken more than 1,164 feet below the Pacific Ocean’s surface captured a frenetic swarm of thousands of red crabs in very low oxygen, acidic waters. →

A massive crab swarm at the bottom of the Pacific Ocean near Panama was just captured on video for the first time.

The swarm, consisting of thousands of red crabs, represents a new southernmost range for the species, Pleuroncodes planipes. Researchers aboard the submersible Deep Rover 2 were both astounded and mesmerized by the unexpected sight, which they recorded about 1,200 feet below the ocean's surface.

"When we dove down in the submarine, we noticed the water became murkier as we got closer to the bottom," project leader Jesús Pineda, a biologist at Woods Hole Oceanographic Institution, said in a press release. "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."

NOAA's 12 Days of the Ocean: Photos

"As we slowly moved down to the bottom of the seafloor, all of the sudden we saw these things," he continued. "At first, we thought they were biogenic rocks or structures. Once we saw them moving - swarming like insects - we couldn't believe it."

Genetic testing identified the crab species, which is known to be abundant off the coast of Baja California. Apparently the crustaceans have a secret life further south too. Information about the discovery is published in the journal PeerJ.

Pineda and his team encountered the swarm while studying the Hannibal Bank Seamount off the Panamanian coast. Seamounts are underwater mountains that usually rise at least 3,280 feet above the ocean floor.

The large aggregation of red crabs was observed along the Northwest flank of the seamount in acidic water with very low levels of oxygen.

"These crabs have been detected before in similar low oxygen conditions," Pineda explained. "It could be that these low oxygen waters provide a refuge for this species from predators."

The frenzy to stay in this crowded spot makes sense when considering the nickname for these crustaceans: tuna crabs. Yellowfin tuna love to eat them, as do many birds, marine mammals and other fish. Humans can eat them too, but do so at risk. That is because the crab's food source consists of phytoplankton that can contain high levels of toxins.

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Despite their efforts to stay alive, the crabs might have perished not long after the video was recorded. Just a few months after the expedition, thousands of red crabs washed ashore onto Southern California beaches during a massive stranding associated with El Niño warming conditions.

DNA testing was employed once again. It revealed that the Panamanian and the Californian crabs are, in fact, the same species.

Pineda and his team plan to return to the Hannibal Seamount to study the region more. The researchers indicated that the deep water, low oxygen and acidic areas of the seamount could reveal how marine life communities might look in the future as the ocean responds to climate change.

Photo by Jesus Pineda, Yogesh Girdhar, Woods Hole Oceanographic Institution

The month of June honors both National Ocean Month and World Ocean Day (June 8). What better time, then, to check out photos of undersea life and be reminded that things "down there" are just as important as things up here on land. Here, a manatee goes about its day. The manatee, also known as a "seacow," is an air-breathing herbivore listed as a federally endangered species. Manatees are slow moving and can't swim quickly away from boats. This often results in collisions that can kill or injure them.

Whales Counted With Space Satellites

Life's a beach. Mom and her baby elephant seal roll around in the sand in Ano Nuevo Island, Calif.

Elephant Seal Calls Tell Rivals Who's Boss

A humpback whale breaches in the Gulf of the Farallones National Marine Sanctuary, off the coast of California.

Distinct Humpback Whale Populations Found in North Pacific

A blue rockfish fans for the camera in Monterey Bay National Marine Sanctuary, in California.

200-Year-Old Fish Caught Off Alaska

A Southern sea otter, aka,

Enhydra lutris nereis

, wonders what all the fuss is about, at South Harbor, Moss Landing, Calif. The World Ocean Day Photo Contest entrant was Submitted by Dr. Steve Lonhart.

PHOTOS: Otter vs. Gator: Otter Wins

A white-lobed sponge brightens up the scenery. It's one of several images of rarely seen deep-sea animals that were captured on camera in Olympic Coast National Marine Sanctuary during a NOAA expedition. Researchers used a NOAA remotely operated vehicle in waters 328 to 656 feet deep off the Olympic Peninsula in Washington State. The research was funded by NOAA's Coral Reef Conservation Program.

Strange, Carnivorous Sponge Found In Deep Sea

This image brimming with colorful marine life is from the Pearl and Hermes Atoll. It's a huge oval coral reef within several internal reefs and is the second largest among the six atolls in the Northwestern Hawaiian Islands.

PHOTOS: Sharks, Marine Mammals Hang in Paradise

Having no backbone isn't always a bad thing! Just ask any octopus. These boneless invertebrates know how to squeeze into (and out of) many a tight spot. They have three hearts, nine brains and blue blood. (Two hearts send blood to the gills, while the third pumper sends it to the rest of the body.)

VIDEO: Octopi Have a Brain in Every Tentacle

Rapture Reef sits within the Northwestern Hawaiian Islands Marine National Monument. The monument encompasses more than 140,000 square miles of ocean and coral reef habitat.

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A sea turtle swims off of the Hawaiian islands.

This seal is eager to wriggle its way back to freedom, as divers release it from fishing nets. Marine debris -- such as these nets -- makes a serious impact on its surroundings. From being an eyesore on a beach to injuring marine life or stopping a 400-ton vessel at sea, it causes problems that are difficult to ignore.

Seal Pup Found in Forest

Grey matter artwork? Nope! It's a sharknose goby (

Elacatinus evelynae

) propped up on brain coral in the U.S. Virgin Islands.