Fascinating Undersea Creatures Found on Expedition

Undersea Specialists are a unique and delightful mainstay of our expeditions and you'll find them on nearly every expedition aboard the National Geographic fleet. These aquatic adventurers plunge into both polar and tropical waters to capture stunning, and often surprising, images of the vibrant world beneath our ships. Here, they share some of their favorite recent finds, from a tiny reef octopus to a magnificent sunflower sea star with 24 arms. Get Inspired By Photos, Videos, Webinars, Stories, And Exclusive Offers. Sign Up

Spotted: Sea Spider

Location: Port Lockroy, Antarctica
Depth: 60 feet
Undersea Specialist: Shaylyn Potter. Follow her @save.our.plankto n

“Though commonly called sea spiders, these gorgeous benthic sea critters aren’t true spiders or even true arachnids. We often refer to them as Pycnogonids, which is their taxonomic class. On the left side of the organism (the head end!) you'll notice an appendage that looks different than the rest. This is the proboscis. The pycnogonid will jam its feeding tube proboscis into soft-bodied prey—like anemones and worms—to suck out nutritious juices. Another fun fact: some sea spider species have three moveable lips."

Spotted: Centolla Crab

Location: Karukinka National Park, Chilean Patagonia
Depth: Approximately 30 feet
Undersea Specialist: Adam Maire. Follow him @adammaire45.

"The southern king crab (Lithodes santolla) is known locally in Patagonia as the Centolla. Related to the king crabs found in high-end seafood restaurants in the United States, Centolla crabs are the focus of fisheries in South America for the same reason. Adults usually live in deep water, up to 700 meters, however, the juveniles are much easier to find since they spend their time hiding in the intertidal zone among kelp fronds and holdfasts, eating and growing until they can survive in the ocean depths. This particular Centolla was lurking in the kelp forest, curiously investigating my camera while looking for bits of dead clams for lunch."

Spotted: Moon Jellies

Location: Ushk Bay, Southeast Alaska
Depth: Just under the surface
Undersea Specialist: Tanish Peelgrane. Follow her @peelgranephotography

"In August of 2021, the National Geographic Venture was in Ushk Bay when we stumbled upon this enormous smack of thousands of moon jellies swimming just below the surface of the water. Besides having the coolest collective name, jellies have been around since long before the dinosaurs, they sometimes glow-in-the-dark, and one species even has the potential to be immortal. These smacktacular drifters are truly fascinating!"

Spotted: Antarctic Incirrate Octopus

Location: Neko Harbour, Antarctica
Depth: 41 feet
Undersea Specialist: Christine West. Follow her @christine_regent_west

“This tiny, bottom-dwelling predator is a reef octopus, the incirrate octopus Pareledone, which is found in Antarctica at depths of 10 feet to over 300 feet. This glacially fed area is characterized by large kelp and a bottom sediment of extremely fine glacial silt, a baby-powder-like substrate that is easily disturbed and must be treaded upon lightly. At only two inches in diameter including arms, this octopus is incredibly unique, crawling across the sea floor to avoid detection rather than pushing itself through the water column which would create clouds of silt and alert predators to its presence. An outstanding find!”

Spotted: Sailors Choice Grunts

Location: The Out Islands of the Bahamas
Undersea Specialist: Shawn Lucas. Follow him @shawn_m_lucas

"Hovering over the shallow 15 foot reef of this stony mustard hill coral in the Bahamas, these Sailors Choice grunts were particularly curious of my camera and allowed me to get rather close. They are named for the 'grunting' sound they make which is produced by their flat teeth plates rubbing together and amplified by their air bladders. In some areas of the world, these fun fish are also known as sweetlips because, well just look at those kissers!"

Spotted: Reef Manta Ray

Location: Hanavave Bay, Fatu Hiva, Marquesas Islands, French Polynesia
Depth: Approximately 5 meters
Undersea Specialist: Maya Santangelo. Follow her @mayasantangelo.

It is very common to find manta rays feeding around the extremely nutrient-rich waters of the Marquesas Islands. Highly evolved with an exceptionally large brain and one of the most efficient filtration mechanisms known to science for feeding on plankton, manta rays display several different feeding strategies.

On this morning in Fatu Hiva, we found a group of several mantas feeding at the surface, cruising back and forth in straight lines with mouths wide open. As this male manta turned to keep feeding, it dived down closer to me and showed off its unique spot pattern on its ventral side (belly), which I photographed for identification. Through citizen science, our expeditions to the Marquesas have greatly contributed to what is known about the little-studied manta ray population in this region of the world (these were the first photo-ID records from Fatu Hiva!). With so many mantas feeding in the area, every time we get in the water is an opportunity to learn more."

Spotted: Sunflower Sea Star

Location: Klewnuggit Inlet, British Columbia, Canada
Depth: Approximately 40 feet
Undersea Specialist: Kim Nesbitt. Follow her @nesbittphotography

I'm always excited to see these sunflower stars (Pycnopodia helianthoides) on dives, but especially now. These amazing animals are the largest and fastest sea star on the planet, but they have been dealing with their own pandemic: Sea Star Wasting Disease. This disease has decimated the population and they are now considered critically endangered across their range. The last healthy population I've seen has been in Northern British Columbia and Southeast Alaska, and it's been wonderful to see such large individuals as well. I'm so happy to dive these waters where we still have a robust undersea environment and healthy ecosystems to photograph."

Spotted: Lion's Mane Jellies

Location: Ketchikan, Alaska
Depth: Surface
Undersea Specialist: Patrick Webster. Follow him @underwaterpat.

"Lion’s mane jellies (Cyanea ferruginea) are the gelatinous pride of the North Pacific. Some of the ocean’s most impressive jellyfishes, members of this genus can grow to be nearly three feet across in diameter with stinging tentacles extending over 100 feet—that’s longer than most blue whales! Associated with fjords and often washing into Southeast Alaska's harbors as juveniles, make sure you take some time to peek overboard for a chance at seeing one of the ocean’s most impressive predators, just like these two photographed with a submerged phone from the Ketchikan docks."

Spotted: Caribbean Reef Shark

Location: The Out Islands of The Bahamas
Depth: 10 feet
Undersea Specialist: Rachel Crane. Follow her @rachelonthereef.

"Sharks all have their own personalities, quirks, and feelings and should be treated with respect, not fear. They are beautiful but fragile apex predators that are critical to the health and survival of our oceans. This elegant female Caribbean reef shark was platonically patrolling a patch reef on one of our snorkel excursions in the Bahama's remote Out Islands."