We have explored large parts of the world but the oceans, that cover most of our planet, are still widely unexplored in the depth. The ROV (remotely operated underwater vehicle) Doc Ricketts recorded its first encounter with a giant jellyfish not long ago, in November 2021. The Monterey Bay Aquarium Research Institute (MBARI) researchers spotted this ghostly yet beautiful creature 990 meters (3,200 feet) deep in the ocean near the coast of California.
Meet the giant phantom jelly: Stygiomedusa gigantea
MBARI’s remotely operated vehicle, Doc Ricketts, has logged thousands of dives, but they encountered this type of “giant phantom jelly” (Stygiomedusa gigantea) only nine times in total. The submersible’s lights revealed a giant phantom jelly with arms that can grow up to 10 meters (33 feet) in length. This colorful deep-sea denizen was only seen nine times before by MBARI researchers due to their shy nature. Still, they managed to record video footage that is fascinating to watch during a recent dive.

A recent article on the MBARI website presents the following figures as facts and estimates regarding this creature.
- Maximum size: more than 1 meter (3.3 feet) across and 10 meters (33 feet) long
- Depth: surface to 6,665 meters (21,900 feet)
- Habitat: midwater, most common in the midnight zone (bathypelagic zone)
- Range: worldwide, except for the Arctic Ocean
- Diet: presumably, plankton and small fishes
MBARI’s observations of Stygiomedusa gigantea have helped illuminate its ecological role in the ocean’s depths. The ROV Tiburon recorded a fish—the pelagic brotula (Thalassobathia pelagica) alongside this giant jelly during an expedition to explore new territory. Researchers watched as one animal visited the other peacefully. It darted inside for brief moments before coming back out again. The open waters offer little shelter, so many creatures find refuge among gelatinous animals abundant here.
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The cameras onboard MBARI’s ROVs allow researchers to make observations without having any interference with the creatures, and now it’s possible to get HD and 4K videos showing stunning details of these mystical and largely unresearched creatures that would otherwise go unnoticed. You can find the published video material from MBARI right beneath the article.
YouTube: An extraordinary deep-sea sighting – The giant phantom jelly
YouTube: Ghostly critters from the deep sea – Stygiomedusa gigantea
Photo credit: The material shown is owned by the Monterey Bay Aquarium Research Institute (MBARI).