We spent much of April glued to a livestream of the deep ocean, filmed from a remotely operated vehicle piloted by researchers aboard the Okeanos Explorer. The expedition crossed the Gulf of Mexico from Galveston, Texas, to St. Petersburg, Florida, and explored parts of the ocean largely unknown to humans.

“It’s about going places no one has ever seen,” mission biologist Stephanie Farrington told Popular Science.

Last week, we published 10 GIFs of some of our favorites of the sea creatures who found themselves in front of the ROV’s cameras. This week, we spoke with expedition leader Kelley Elliott and mission specialist Kasey Cantwell, who reviewed some highlights from the mission and explained exactly what everything was, just in case there was any beast you didn’t recognize during the livestream. View our gallery (above) of some of the most amazing deep-sea sights.

Bonus GIFs! Here are two GIFs from the livestream, showing deep-ocean creatures having a snack. The first is a sea cucumber munching on sediment; the second is a sea urchin taking a bite of coral.

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Unidentified Jellyfish

The researchers aren’t sure what to call this mysterious jelly, though they guess it could be of the order Narcomedusae. Here, it swims with bent tentacles.

Dumbo Octopus

Here, a dumbo octopus swims away from the ROV using its ear-like fins. According to the researchers, this coiled-tentacle posture has never before been observed in this species.

Rare Jelly

This ctenophore (tee-nuh-for), with a blood-red gut, surprised the scientists with its bright yellow coloring when it floated in front of the ROV’s camera. It was later identified as Lampocteis cruentiventer. Jelly-like ctenophora swim using hair-like cilia, and most are hermaphrodites.

Squat Lobster

A spiky lobster sits on a black coral, presumably waiting for food to float by.

Shipwreck Debris

Sea creatures live in the wreckage of a 19th-century merchant vessel. Items here include ceramic jugs, likely produced in the Yucatan, glass bottles, and a compass.

Shipwreck, With Anchor

Here is the bow section of the shipwreck, known as Monterrey B. You can see the large iron anchor surrounded by glass jugs.


The Roman numerals are still visible on the face of this timepiece, two hundred years after it sank to the bottom of the ocean. The hands appear to mark 6:30.

Urchin Eats Coral

As the ROV camera operators zoomed in on this sea urchin, the livestream narrators wondered aloud what it was doing sitting so close to a branch of white octocoral. A few seconds later, a set of teeth popped out, snapped off a piece of coral, and then retracted into the urchin’s body. This was one of the mission’s most exciting discoveries, as images of deep-sea predation are rare.

Carrier Crab, With Hat

The livestream narrators had a good laugh at this carrier crab when they realized it was using its hind legs to hold a piece of sponge over itself. Why? The researchers weren’t sure.

Sea Cucumber

Sea cucumbers ingest sediment on the ocean floor and digest the organic bits.

Swimming Cucumber

Here’s a transparent sea cucumber.

Deep-Sea Squid

This little member of the family Cranchiidae has a large body chamber filled with ammonia to keep it buoyant. The dark spots at the ends of its arms are organs called photophores that can produce flashes of light.

Squid Eggs

These bobtail squid eggs are very close to hatching; in fact, the ROV operators moved on quickly, worried that the bright light could cause them to hatch prematurely. The dark spots within the eggs are the baby squid’s eyes.

More Squid Eggs

Here is another batch of squid eggs. These ones have a bit longer to go before they hatch.

Fish With Anemone

This fish seemed to look right at the ROV. In the background is a flytrap anemone.

Brittle Star

A brittle star has wound its arms around a colony of Paramuricea octocoral.

Soft Coral

This lovely stalk is a member of Aquaumbridae, a recently discovered family of soft coral. The bright white spots are coral eggs.

Oil Bubbles

Here, chemosynthetic mussels and sea urchins live on a natural oil seep. On the right, you can see an oil bubble caught in a mussel’s mucus.

Romantic Crabs

The ROV caught two golden crabs mating under a coral colony.

Tar Lily

As the ROV approached this site, the Okeanos team assumed they had discovered another ancient shipwreck. But they soon realized the structure was not manmade—instead, the extrusions appear to be the remains of an asphalt volcano.

Deep Discoverer

Here’s a view of NOAA’s ROV, named Deep Discoverer, as it explores Bryant Canyon. This shows just how pitch-black it is outside the LED beams.
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