Mesmerising, rare dumbo octopus filmed in the deep sea | National Geographic Australia



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SCIENTISTS USING A remotely operated vehicle to survey the seafloor earlier this week spotted something spooky: a ghostly creature with pale skin, bulging eyes, and what looked like translucent wings—the elusive dumbo octopus.

Scientists aboard the E/V Nautilus were exploring the Davidson Seamount, an inactive undersea volcano off the coast of California, when the spectral octopus greeted their submersible. As it drifted into full view, the team couldn’t contain its excitement. (Watch a gulper eel inflate and deflate itself, shocking scientists).

“Oh my, it’s so cute”, says one team member. “I love me a good cephalopod”, says another.

Seeing this deep-sea dweller was a treat for the researchers says Chad King, Nautilus’ chief scientist. “It’s very exciting to see one live”, King says. “It’s something you don’t come across every day”.

Darling dumbos

Dumbo octopuses (Grimpoteuthis sp.) inhabit the deepest, darkest parts of the Atlantic and Pacific Oceans, which makes studying them difficult. This dumbo was found two miles below the surface; others have been found at twice that depth.

Dumbo octopuses spend much of their lives suspended just above the seafloor. This is where they lay their eggs and hunt for prey such as crustaceans, bivalves, and worms.

OCTOPUSES: MASTERS OF DISGUISE AND AGILE HUNTERS

Octopuses are masters at flying under the radar, changing their colouration and texture to match their surroundings in seconds. The above octopus seen in the Bonin Islands near Japan in 2008.
PHOTOGRAPH BY BRIAN J. SKERRY

Like the animated elephant the species is named after, the dumbo octopus flies through the water by flapping a set of two ear-like fins on the sides of its body. However, this isn’t the dumbo’s only means of propulsion. Its eight legs are connected by a web of skin, not unlike an umbrella. Contracting this webbing can give these cephalopods a quick burst of speed, which comes in handy when evading agile predators such as tunas and sharks. Dumbos are also able to crawl across the seafloor using their tentacles.

There are more than a dozen species of dumbo octopus, and they come in many different shapes and sizes. Although most species of dumbo measure between 20 and 30 centimetres long, some can reach upwards of 1.8 metres in length. Like all octopuses, they also have the ability to change their skin colour at will. But unlike other octopuses, dumbos don’t produce ink. As an alternative defence, some have tentacles lined with sharp spines.

“I think they are the cutest things in the world”, King says. And based on the candid reactions of his colleagues, which can be heard in the video, he isn’t the only one. King says his team can’t help but “geek out” when it comes across such charismatic fauna. “This is the stuff we’re passionate about!”

Sunken treasure

As delighted as the crew was to see this dumbo, time was tight, so they had to move on. The Nautilus had bigger figurative fish to fry. The ROV and her crew had travelled 128 kilometres off the coast of Monterey, California, to see what natural treasures are hidden within the boundaries of the Davidson Seamount.

The Davidson Seamount is one of the largest in US waters. From base to crest, the seamount measures 2,280 metres tall, yet its summit is still 1,250 metres below the sea surface.

King says the seamount is teeming with life, but what kinds of life remains a mystery. The goal of Tuesday’s dive was to survey a completely unexplored rocky outcropping to the southeast of the seamount. In addition to spotting the charming cephalopod, the crew discovered fields of corals and sponges that King says “looked like they came right out of a Dr Seuss book”.

“There were 3-metre-tall pink bubblegum corals and sponges big enough to walk into”, King says.

The Davidson Seamount was added to the Monterey Bay National Marine Sanctuary in 2009 after ecological surveys, spearheaded by the Monterey Bay Aquarium Research Institute (MBARI) and National Oceanic and Atmospheric Administration (NOAA), characterised the inactive volcano as an “undersea oasis”. King says the seamount boasts large coral forests, vast sponge fields, and a myriad of unidentified benthic species.

Deep respect

That’s where the Nautilus’ mission comes in. Founded by Robert Ballard, discoverer of the sunken R.M.S. Titanic and a National Geographic Explorer-at-Large, the Nautilus Exploration Program is on a mission to explore the depths of the Pacific Ocean.

Tuesday’s dive was one of several the Nautilus’ ROV will be conducting this year. King hopes that his underwater exploration, which is live-streamed on Twitter, will inspire others to care about conserving seamounts and other out-of-sight ocean habitats. (How much do you know about the deep sea?)

“This is a very special place”, he says. “We want to protect it for posterity and to ensure these coral and sponge species survive”.



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