Cliffside Corals in Marshall Islands Deep Sea

Journey with us into the depths of the National Marine Sanctuary of Bikar and Bokak in the Marshall Islands. In 2025, while exploring a little over 2,000 meters deep, we found a high-density community that certainly warrants highlighting. Watch as ROV Hercules travels past cliffsides covered in corals, sponges, and associates, and Corps of Exploration members inside the Nautilus control van observe this stunning deep-sea habitat. Spot crinoids and squat lobsters populating these coral colonies, alongside glass sponges, urchins, and more. You’ll even see the team work together to sample a Hemicorallium coral and investigate carnivorous sponges. For years after exploring, the learning continues as researchers will annotate the deep-sea video in an attempt to understand more about the biology and ecology of the region.

The Republic of the Marshall Islands is an atoll-based country of over 1,200 islands surrounded by 2.13 million square kilometers of ocean, the vast majority of which has never been mapped or surveyed. Despite data gaps, it’s known that the deep sea of Aolepān Aorōkin Ṃajeḷ hosts rich and diverse marine resources, including these amazing animals, over 300 unexplored seamounts, extensive deep-sea ridges, and escarpments. This expedition was developed in collaboration and consultation with the Marshall Islands Marine Resources Authority and other local stakeholders and funded by NOAA Ocean Exploration via the Ocean Exploration Cooperative Institute.