''Cyanea nozakii'' or ''Cyanea nozaki'' (misspelling), commonly known as the ghost jellyfish, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...

found in the northern Pacific Ocean near the coasts of China and Japan. Along with other species of large jellyfish, it is showing a greater tendency to appear in large numbers and cause blooms.

Description

The medusa stage of ''Cyanea nozakii'' has a distinctive flat-topped bell which can grow to a diameter of . The bell is usually cream or pale yellow in colour with a dark centre and a translucent rim. It has eight large marginal lobes and eight bundles of thread-like marginal

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s. There may be a hundred or more tentacles in each bundle which are either translucent or a reddish colour, and can extend for . Under the centre of the bell is the

manubrium The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sha ...

, the mouth being surrounded by a tangled mass of rusty-brown or orange oral tentacles.

Distribution

''Cyanea nozakii'' is found around the coasts of China and Japan. Since the beginning of this century, ''Cyanea nozakii'' has become more common, with mass aggregations occurring. In 2004 this happened in Liaodong Bay in Northeast China and it was noticed that commercial catches of the edible jellyfish ''

Rhopilema esculentum ''Rhopilema esculentum'', the flame jellyfish, is a species of jellyfish native to the warm temperate waters of the Pacific Ocean. It is a popular seafood in southeastern Asia. In the 1980s, research was undertaken in China into its aquaculture ...

'' were adversely affected. In 2011, a bloom of large jellyfish appeared off the coast of

Qingdao Qingdao (, also spelled Tsingtao; , Mandarin: ) is a major city in eastern Shandong Province. The city's name in Chinese characters literally means " azure island". Located on China's Yellow Sea coast, it is a major nodal city of the One Belt ...

, in what a Japanese scientist had said would be a "non-jellyfish year". These jellyfish largely consisted of '' Nemopilema nomurai'', ''

Aurelia aurita ''Aurelia aurita'' (also called the common jellyfish, moon jellyfish, moon jelly or saucer jelly) is a species of the genus ''Aurelia''. All species in the genus are very similar, and it is difficult to identify ''Aurelia'' medusae without geneti ...

'' and ''Cyanea nozakii'', and the Institute of Oceanology, Chinese Academy of Sciences is undertaking research into how such blooms develop and their social and ecological effects. Reporting in 2014, the study found that the blooms were likely to be an indicator of worsening ecosystem health. They are linked to variations in sea temperature, increased pollution of coastal waters, overfishing by China, bottom trawling, and the depletion of oxygen levels due to algal blooms. These factors are favouring the survival of the polyp stage of the jellyfish life cycle and thus contributing to greater numbers of the jellyfish medusae.

Ecology

A number of species of juvenile fish associate with this jellyfish, making use of the protection provided by its stinging tentacles. The

razorbelly scad The razorbelly scad (''Alepes kleinii'') (also known as the banded scad, golden scad and goggle-eye scad) is a small species of tropical marine fish in the jack family, Carangidae. The species inhabits coastal waters in the Indo-Pacific, from Pak ...

(''Alepes kleinii'') and

Malabar trevally The Malabar trevally (''Carangoides malabaricus''), also known as the Malabar jack, Malabar kingfish or nakedshield kingfish, is a species of large :wiktionary:inshore, inshore ocean, marine fish of the jack Family (biology), family, Carangidae. ...

(''Carangoides malabaricus'') are two such fish; large numbers of tiny fish congregate around and among the fine tentacles. Each fish either avoids touching the tentacles or is relatively unaffected by their mild sting, and if the jellyfish is netted, the little fishes stay with it and may get more heavily stung, and consequently die. As they get larger, the fish leave the jellyfish and live independently. Another organism that lives in association with the jellyfish is the stalked barnacle ''

Alepas pacifica ''Alepas pacifica'' is a species of goose barnacle in the family Heteralepadidae. It is a pelagic species and is an obligate associate of various species of jellyfish. It mainly occurs in the Pacific Ocean. Description ''Alepas pacifica'' is a ...

'' which hangs from the margin of the bell. It is translucent and a similar whitish colour to the jellyfish which makes it inconspicuous. It is a permanent resident, always associating with the jellyfish, and makes use of the rich food supply in the surface waters in which the jellyfish floats.

Research

A collagen peptide, shown to have immune-enhancing activity, has been extracted from ''Cyanea nozakii''. A

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A p ...

for this product has been applied for.

References

{{Taxonbar, from=Q2060326 Cyaneidae Animals described in 1891 Cnidarians of the Pacific Ocean