OET’s Top 10 WOW Moments of 2025
Take a look back at some of the biggest “WOW” moments of 2025 for Ocean Exploration Trust (OET) and the Corps of Exploration as we explored the sea and tested new technology across the Pacific Ocean.
Honorable Mention: ROV Hercules Upgrade: New Kraft Manipulator Arm
Although remotely operated vehicle (ROV) Hercules was first deployed more than 20 years old, each year upgrades of equipment keep the vehicle advancing new technology and functioning at the highest level for exploration. In the 2025 offseason, after decades of seafloor service, the ROV engineering team replaced Hercules' right arm with a new model, Kraft Predator manipulator. With seven-function control, over 79 inches of reach, and a lift capacity of 500 pounds, this arm sets the team up for science operations for many seasons ahead.
10. (Not) Dumbo Octopus Wows Team With Tentacles
Our Corps of Exploration came across this cephalopod while exploring the abyssal plain in the waters of the Cook Islands, over 5,000 meters (16,400 feet) deep. Watch until the end and you’ll be treated to a gorgeous look at the underside of this octopus, including the rows of suckers on its eight tentacles. Each tentacle is connected by a web of skin, allowing for the graceful pulsing umbrella movement we were lucky enough to catch on camera of ROV Little Hercules. While originally IDed as a dumbo octopus, we now believe this individual octopus to be in the Cirroteuthidae family (probably Cirrothauma).
9. Large Chimaera on Never-Before-Surveyed Seamount
While exploring Ļōjabōn-Bar Seamount in the waters of the Marshall Islands during the NA174 expedition, we were excited at the sight of this absolutely stunning (and rather large) chimaera. This cartilaginous fish from the Order Chimaeriformes are related to sharks and commonly called a ghost shark, rat fish, spook fish, or rabbit fish. Most chimaera live in the deep sea and this one was caught on video by ROV Hercules at 1,615 meters. What a treat to see on the first ever dive on Ļōjabōn-Bar Seamount, which lies roughly 85 nm north of Bikini Atoll!
8. Beautiful CO2 Bubbles From Underwater Volcano
While diving on the summit ridge of Ahyi Seamount, our ROVs were enveloped by a massive curtain of carbon dioxide (CO2) bubbles emanating from the volcanic seafloor. Ahyi Seamount has erupted five times since 2000, which led the team to return to explore the area for changes. Before the dive, the team onboard E/V Nautilus remapped this shallow submarine volcano within Mariana Trench Marine National Monument. Onboard scientists helped analyze the water column data and identified a massive, distinct bubble plume on the summit ridge formed by recent volcanic activity.
7. R(eel)y Photogenic Moray Pair on Ahyi Seamount
Despite looking like Disney's Flotsam and Jetsam, these two eels showcase the wide color variability of the species Gymnothorax genus of moray eels. These Gymnothorax berndti and Gymnothorax elegant were filmed by ROV Hercules during NA171 while exploring the summit of Ahyi Seamount, between Maug and Uracus in the Northern Mariana Islands. Living together as "roommates" as the team jokes, is not uncommon for morays, which are known to even hunt cooperatively on the reef with groupers.
6. Gorgeous Glass Squid in the Solomon Islands
While exploring the deep sea around the Solomon Islands during NA173, we caught sight of this gorgeous glass squid (family Cranchiidae) with ROV Hercules. Glass squid (aka cockatoo squid), have tiny pigment sacs (called chromatophores) that help them change colors (and even appear transparent) in the ocean. While this individual as spotted at 880 meters, some glass squid have been observed as deep as 2,000 meters. They have internal cavities that they’ll fill with ammonium chloride (which is lighter than seawater) to maintain buoyancy, conserve energy, and survive in the deep sea.
5. Shallow Water Biodiversity in the Marianas
During the NA171 expedition, ROV Hercules went somewhere it doesn’t normally go: the shallow ocean! In this case, shallow is a relative term, but for our deep-diving ROV, exploring depths of only up to 500 meters is certainly rare. While exploring Ahyi and West Mariana Seamounts, we saw some amazing views of the biodiversity that call these shallow submarine volcanoes home, including a variety of requiem sharks, trumpet fish, sea stars, and more.
4. Black Smokers of Hafa Adai Vent Field
During the NA171 expedition, ROV Hercules explored the Hafa Adai Vent Field in the Mariana back-arc: the first visit to this extraordinary site since its discovery in 2016. Co-Lead Scientist Bill Chadwick explains how different the site looks from the last time he saw it, a visual example of the region’s ongoing hydrothermal and volcanic activity. Hot vent fluids from these chimneys include metals leeched from seafloor rocks, giving it the distinctive black color and earning the name “black smokers.” This extreme habitat with temperatures that have measured up to 350°C can surprisingly support a variety of species, such as squat lobsters (Munidopsis sp.), anemones (Marianactis bythios), and shrimp (Rimicaris sp.).
3. IJN Destroyer Teruzuki Discovered
For the first time, a team of scientists and explorers aboard OET’s E/V Nautilus during the NA173 expedition located the World War II Imperial Japanese Navy destroyer Teruzuki (照月). Using ROVs Hercules and Atalanta, we explored the wreck after University of New Hampshire’s USV DriX’s targeted mapping identified a site consistent with the sinking location of the destroyer. Lying on the seabed at over 800 meters in the Solomon Islands, this is the first time anyone has laid eyes on Teruzuki since it was sunk in WWII’s naval battles off Guadalcanal.
2. Rare Bigfin Squid in the Cook Islands
During our NA176 expedition exploring the waters of the Cook Islands, we encountered this bigfin squid (genus Magnapinna) over 5,100 meters deep. These cephalopods are rarely ever seen by humans (with fewer than two dozen recorded sightings and no physical collections), since they are the only squid known to live as deep as the hadal zone. The squid’s distinctive morphology includes extra-long tentacles and arms with microscopic suckers, and “elbows” likely used to catch and eat planktonic crustaceans. Moments like this —meeting rare ocean life —remind us all how much we have to learn about the deep ocean.
1. Severed Bow of USS New Orleans Discovered in Iron Bottom Sound
During NA173, our team of scientists and explorers aboard E/V Nautilus located and imaged the bow blown off the World War II heavy cruiser USS New Orleans for the first time. Using ROVs to investigate a target found during seafloor mapping operations by University of New Hampshire’s uncrewed surface vessel DriX, the team found the bow resting at ~675 meters deep in the Solomon Islands’ Iron Bottom Sound and reilluminated this improbable story. Over eighty years after losing its bow in battle the team imaged the site with onboard archaeologists and experts from all former combatant nations contributing via livestreaming telepresence. Together, this team spotted details in the ship’s structure, painting, and anchor to positively identify the wreckage as New Orleans.
