Biodiversity of Ruby Seamount in the Marianas

Geology wasn’t the only thing that wowed our NA180 Corps of Exploration as they dove ROVs Little Hercules and Atalanta on Ruby Seamount, only 50 km northwest of Saipan. While diving on this active submarine volcano, which last erupted in September 2023, we witnessed a wealth of wildlife, including schools of small pink bait fish and a spectacularly spotted octopus.

Spot a Chaunax anglerfish around 339 meters deep, waiting to ambush its next meal, and neon-colored yellowspot groppo fish (Grammatonotus xanthostigma), which would look at home on a coral reef. Keep watching, and you’ll also see a benthic ctenophore with an uncanny resemblance to a rabbit, followed by a hydromedusa moving through the water column via jet propulsion. What a line-up of diversity live from the deep-sea!

Ocean Exploration Trust's Deep-Sea Habitats in the Mariana Islands I & II (NA179 & NA180) expeditions are primarily supported by NOAA Ocean Exploration via the Ocean Exploration Cooperative Institute, with additional support from the Bureau of Ocean Energy Management for AUV Sentry’s participation.