Animals

Alien-like giant phantom jellyfish spotted in frigid waters off Antarctica

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4w ago

Mar 31, 2024 / 5951 Views

A brownish giant phantom jellyfish swimming in the blue water. — A giant phantom jellyfish (*Stygiomedusa gigantea*) encountered off the Antarctic Peninsula during a Viking cruise. (Image credit: Antony Gilbert)

Rare sightings of giant phantom jellyfish — deep-sea creatures that look like UFO spaceships with thick ribbons streaming from their undersides — have been reported by cruise liner passengers who spotted the otherworldly animals off the coast of Antarctica, a new study finds.

The giant phantom jellyfish (Stygiomedusa gigantea), one of the deep sea's largest invertebrate predators, met the guests while they were riding in a submersible deployed by cruise line operator Viking in early 2022. Researchers estimated that the jellyfish were longer than 16 feet (5 meters), with one stretching to at least 33 feet (10 m) in length, according to a study published Jan. 30 in the journal Polar Research.

Study first author Daniel Moore first realized guests had encountered the giant phantom when he saw a picture of one on a guest's camera. "I instantly recognised it for what it was and, given the rarity of sightings, was flooded with excitement," Moore, one of Viking's chief scientists, told Live Science in an email.

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A second giant phantom jellyfish spotted by the Viking team. (Image credit: Mark Niesink)

Giant Phantom jellyfish live in every ocean except for the Arctic Ocean. However, because these cryptic creatures typically swim deep below the surface, they are scarcely seen by humans. The new study describes direct observations of three different jellyfish made during submersible dives off the Antarctic Peninsula.

"On every sighting the jellyfish appears to be swimming slowly, gently pulsing its bell for propulsion," Moore said. "They don't appear to have shown any inclination towards the lights of the submersible or reaction to our presence."

The jellyfish were spotted at depths of 260 feet (80 m), 285 feet (87 m) and 920 feet (280 m). Giant phantom jellyfish primarily occupy depths of below 3,280 feet (1,000 m), but they are encountered higher up in the Southern Ocean, or Antarctic Ocean. It's not yet known why they hang out in relatively shallow waters around Antarctica.