Mysterious Deep Sea Jellyfish Delights Scientists
This deep sea helmut jelly (Periphylla sp.), spotted during a dive southwest of Johnston Atoll In international waters near the Pacific Remote Islands Marine National Monument during the H1993 dive of the NA153 expedition, fascinated our Corps of Exploration. Whether you think it looks like a baby bottle cap, a UFO, or an acorn, you won’t be disappointed with this creepy-cool gelatinous cnidarian. Helmet jellies are 90% water and are capable of bioluminescence. While this specimen looks to be around 20cm in length, these deep sea critters can get up to 30cm long.
The ancient seamounts southwest of Johnston Atoll (beyond US national jurisdiction but close to the Pacific Remote Island Marine National Monument) remain mostly unexplored, and all data collected during this expedition will help address deep-water habitat scientific knowledge gaps, as a management plan is under development now for the region.
Deep Sea Biodiversity & Ancient Seamount Exploration near Johnston Atoll
In August 2023, we will return to the Central Pacific for 27 days of exploration within the Johnston Atoll Unit of the Pacific Remote Islands Marine National Monument (PRIMNM), starting and ending in Honolulu.
