Rare Giant Phantom Jellyfish Spotted Off Argentina Coast

Scientists exploring the deep sea off Argentina have captured rare footage of one of the world’s most elusive ocean creatures — the giant phantom jellyfish.

The sighting was made during a research expedition exploring Argentina’s continental shelf. Underwater robot pilots filmed the jellyfish at around 250 metres below the surface. The discovery surprised even experienced marine researchers, as this species is rarely seen alive in the wild.

What is the giant phantom jellyfish?

The giant phantom jellyfish is scientifically known as Stygiomedusa gigantea. It is one of the largest jellyfish species ever recorded.

Its bell can grow up to 1 metre wide, while its four ribbon-like arms can stretch up to 10 metres long. Unlike many jellyfish, it does not have stinging tentacles. Instead, it uses its long arms to trap prey such as plankton and small fish.

During the sighting, researchers also noticed juvenile fish swimming around the jellyfish’s bell, appearing calm and unaffected.

Why the sighting is rare

The species was first collected in the late 1800s and was officially named in 1910. However, despite its large size, it remains extremely rare.

Scientists say that since 1910, there have been only 126 recorded sightings worldwide, including jellyfish caught accidentally in fishing nets. That averages to just about one sighting per year globally.

The main reason is that this jellyfish usually lives in deep water, mostly between 1,000 and 3,000 metres. It has also been observed at depths of more than 6 kilometres. In the Southern Ocean, it has sometimes been seen at shallower depths, which may explain why it was filmed at 250 metres.

What scientists still don’t know

Because sightings are so uncommon, scientists still know very little about the giant phantom jellyfish. Its full distribution is not completely confirmed, and key details about its behaviour, reproduction and environmental preferences remain unclear.

Researchers say every new sighting is important because it offers a rare chance to study the species in its natural habitat.

More discoveries during the expedition

The jellyfish sighting happened during an Argentinian-led expedition aboard the Schmidt Ocean Institute’s research vessel R/V Falkor. The team travelled along Argentina’s coastline, from Buenos Aires to waters near Tierra del Fuego.

The expedition also documented major deep-sea discoveries, including the largest known Bathelia candida coral reef in the global ocean, as well as several other reef systems.

Scientists also reported 28 suspected new species, including worms, corals, sea urchins, sea snails and sea anemones.

A reminder of deep-sea mysteries

Marine scientists say the Argentine deep sea remains largely unexplored. The rare footage of the giant phantom jellyfish highlights how many ocean species and ecosystems still remain unknown.

As deep-sea exploration technology improves, researchers hope more sightings will help them understand the life that exists far below the ocean’s surface.