Sea Pen Forest in Papahānaumokuākea
While diving over 450 meters (1,476 feet) deep on the slopes of Nīhoa within Papahānaumokuākea National Marine Sanctuary, our ROVs flew above a stunning forest of sea pens living anchored into soft sediment on the seafloor. Sea pens are colonial soft corals belonging to the order Pennatulacea. These marine invertebrates may not look like the pens we use today but were named for their plumy resemblance to historic quill-based writing implements. Did you know that scientists have found that these animals glow in the dark?
A “forest” of such density reminds us of how important National Marine Sanctuaries are in preserving undisturbed habitats for deep-sea populations. Other animals observed along with the sea pens include pink mushroom corals, a genus Chrionema ray-finned fish, and the famous Hawaiian gold coral (Kulamanamana haumeaae) zooanthid. Keep watching and you’ll spot squat lobsters, carrier crabs, and fish and corals of all different colors!
Ocean Exploration Trust's NA182 Exploration of the Hawaiian Islands was funded by NOAA Ocean Exploration via the NOAA Ocean Exploration Cooperative Institute.
Deep-Sea Habitats of the Hawaiian Archipelago
Our final OECI-sponsored expedition of 2026 brings E/V Nautilus back to the Hawaiian Islands. While nearshore waters surrounding the islands have been relatively well surveyed, many offshore areas remain completely unexplored, hindering efforts to effectively manage the resources of this unique region.
