The ghostly giant is an extremely rare sight and we now have some great images to help us learn about it.
Out in the darkness of the midnight ocean, a Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) spots a billowing curtain of crimson. As the submersible zooms in for a closer look, its lights reveal the outline of a giant jellyfish (Stygiomedusa gigantea).
Known in English as the “giant ghost jelly,” each sighting of this mysterious animal is a celebration for ocean researchers. It was first collected in 1899, but since then scientists have only encountered this animal about 100 times, although we are talking about a large animal that seems to have a worldwide distribution. So why the few sightings? Well, accessing the deep-sea habitat of these animals has been quite a challenge.
This is where MBARI’s remotely operated devices come into the picture. Such vehicles have gone a long way in learning about life in the deep sea and MBARI’s ROV Doc Ricketts has now further increased our knowledge by providing the incredible footage below. The ROV spotted this giant ghost jellyfish in November 2021, at a depth of 3,200 feet (990 meters) in Monterey Bay. This deep-sea inhabitant has a bell that is more than one meter (3.3 ft) wide and trails four ribbon-like oral (or mouth) arms that can grow more than 10 meters (33 ft) long.
Even today, we know very little about the giant ghost jelly. Historically, scientists relied on trawls to study animals in the deep sea, and while these nets can be effective for studying hardy animals like squid, crustaceans, or fish, jellyfish turn into a gelatinous substance in them. The cameras on MBARI’s ROVs, on the other hand, have allowed researchers to study these animals intact in their natural environment. High-definition images of the giant ghost jellyfish capture amazing details about the animal’s appearance and behavior that scientists would not have been able to see with a trawl-caught specimen.
MBARI’s observations of the giant ghost jellyfish have helped illuminate the animal’s ecological role in the deep ocean. During an expedition to the Gulf of California, for example, another MBARI ROV, Tiburon, recorded a fish, the pelagic brotula (Thalassobathia pelagica), alongside a giant ghost jellyfish. The researchers watched as the brotula hovered over its host’s rattlesnake and swam in and out of the jellyfish’s massive oral arms. As the open depths of the midnight zone offer little shelter, many creatures find refuge in the gelatinous animals that abound in this environment.
Here are some more amazing photos and facts about MBARI’s Giant Ghost Jelly:
The giant ghost jellyfish (Stygiomedusa gigantea) has an unusual appearance and remarkable size, and it also exhibits a unique life history. Most jellyfish alternate between a swimming stage (called a medusa) and an attached stage (called a polyp or hydroid). But female giant jellyfish raise their young in pouches under that wide bell and give birth to their young live. Image: © 2007 MBARI
Encountering the giant ghost jellyfish is a rare treat, even for MBARI researchers. In more than 34 years of deep-sea research, they have only observed this species nine times. This individual was seen with the ROV Doc Ricketts at a depth of 990 meters (3,200 feet) in Monterey Bay. Image: © 2021 MBARI
The giant ghost jellyfish has a reddish coloration, similar to many other deep-sea animals. Since red light cannot penetrate to the depths of the ocean, animals that are red appear black and camouflaged in the dark. Scientists aren’t sure which animals might prey on the giant ghost jellyfish, but its crimson color and sheer size likely help deter most predators. Image: © 2018 MBARI
The giant ghost jellyfish was first collected in 1899. Since then, scientists have only encountered this animal about 100 times. It appears to have a worldwide distribution and has been recorded from all ocean basins except the Arctic. The challenges of accessing its deep-sea habitat contribute to the relative scarcity of sightings of such a large and widely distributed species. MBARI’s Tiburon ROV observed this individual in the outer reaches of Monterey Canyon at a depth of approximately 1,100 meters (3,600 feet). Image: © 2007 MBARI
MBARI’s Shark ROV recorded this giant ghost jellyfish as it floated in currents just above the deep sea floor during an expedition to the Channel Islands off the coast of southern California. Image: © 2005 MBARI
The giant ghost jelly has no tentacles. Instead, it uses four blanket-like oral (or buccal) arms lined with stinging cells to stun prey. We don’t know what the giant ghost jellyfish eats, but scientists suspect that it feeds on plankton and perhaps small fish. Image: © 2007 MBARI
Most observations of the giant ghost jellyfish have been in deep water. MBARI has recorded this species at depths of 750 to 2,200 meters (2,500 to 7,200 ft) in Monterey Bay, the Juan de Fuca Ridge, and the Gulf of California. In the cold waters around Antarctica, the species has been seen in shallow water. Image: © 2021 MBARI
