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

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

jellyfish Jellyfish, also known as sea jellies or simply jellies, are the #Life cycle, medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animal ...

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 In Greek mythology, Medusa (; ), also called Gorgo () or the Gorgon, was one of the three Gorgons. Medusa is generally described as a woman with living snakes in place of hair; her appearance was so hideous that anyone who looked upon her wa ...

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 (: sternums or sterna) 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, human lung, lungs, and ma ...

, 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 Liaodong Bay is largest and longest of the three main bays of the Bohai Sea, the innermost gulf of the Yellow Sea. The other two bays are Laizhou Bay to the south and Bohai Bay to the southwest. Although named after the Liaodong Peninsula (wh ...

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, Mandarin: , (Qingdao Mandarin: t͡ɕʰiŋ˧˩ tɒ˥) is a prefecture-level city in the eastern Shandong Province of China. Located on China's Yellow Sea coast, Qingdao was long an important fortress. In 1897, the city was ceded to G ...

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

Nemopilema nomurai is a very large rhizostome jellyfish, in the same size class as the lion's mane jellyfish, the largest cnidarian in the world. It is edible but not considered high quality. It is the only species in the monotypic genus ''Nemopilema.'' Commonl ...

'', ''

Aurelia aurita ''Aurelia aurita'' (also called the common jellyfish, moon jellyfish, moon jelly or saucer jelly) is a species of the family (biology), family Ulmaridae. All species in the genus are very similar, and it is difficult to identify ''Aurelia (cnida ...

'' 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 (''Alepes kleinii'') and Malabar trevally (''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 sufficiency of disclosure, enabling discl ...

for this product has been applied for.

References

{{Taxonbar, from=Q2060326 Cyaneidae Animals described in 1891 Cnidarians of the Pacific Ocean Taxa named by Kamakichi Kishinouye