Introduction
The genus Cephea are known as the crown jellyfish. They are “true jellyfish” in the family Cephidae. The genus has three known species, all marine, Cephea cephea, Cephea octostyla, and Cephea coerula. They can be identified by their three or more interrhopalar canals in each octant, an exumbrella with large, conspicuous warts on the center and mouth-arms with long narrow filaments. The Cephea Cephea, the most researched of the three is also known as the cauliflower jelly. This jelly has eight oral arms that are divided into a large, curly-looking surface area which resemble a cauliflower. While this species is known for its unique appearance and vibrant colors it’s also an delicacy consumed in Japan and China.
History
C. cephea was initially described in 1775 by Forskål while the first experimental insights into its life cycle didn’t occur until 1966 by Sugiura.
Description and Anatomy
The genus Cephea can be identified by its exumbrella with large, conspicuous warts on center of it. The exumbrella of a jellyfish is the top the umbrella in its free floating medusa form. It has 8 large branching oral arms with long, narrow filaments. It also has eight main radial canals corresponding with the rhopalia. Rhopalia ( singular rhopalia) are small sensory in jellyfish that lie in marginal indentations around the bell. These structures are used for sensing light(eyespot) or movement and direction in respect to gravity(statoliths). They have three or more interrhopalar canals(without rhopalia) in each octant. They do not appear to have a definite ring canal which is the the circular canal in the edge of the umbrella of a jellyfish that links the radial canals. They have a small and round subgenital ostia, without papillae. The subgenital cavities are not always divided into 4 completely separated chambers. The 8 rhopalia ocelli which are eyespots and lack a sensory pit on exumbrella. The subumbrella circular musculature is weak. They have a typical life span of 3 to 6 months and range in 50 to 60 cm in diameter, slightly larger than a foot. For the individual species Cephea Cephea, they can be characterized by their multiple wart-like projections on top of the central mound of their bell, which is surrounded by a moat. The thin frilled skirt around the crown is used for swimming and its eight oral arms divide into what resembles the flesh of a cauliflower which is where to name cauliflower jelly originated. Currently the Monterey Bay Aquarium in California has an exhibit of Cephea Cephea that they have successfully raised from polyps to adulthood. In studying the species at the aquarium, they have found the species to grow at an extremely fast rate—from just a few millimeters to the size of a dime in two to three weeks. They have also observed its array of about 30 “spikes” emanating from the broad, circular bell, its eight mouth-arms and more than 100 long, tapering, pointed appendages that spring from their pinkish-purple central stomach.
Classification
The genus Cephea belongs to the kingdom Animalia, Phylum Cnidaria, Class Scyphozoa, Subclass Discomedusae, Order Rhizostomeae, Suborder Kolpophoras, and Family Cepheidae. There have been four species of Cephea recognized by most researchers. One has not been taxonomically confirmed (C. octostyla) and another (C. conifera) is considered by some researchers to be a morphotype of C. cephea (WoRMS 2015).
Distribution and Habitat
The genus Cephea are located in the Indo-Pacific region, the Red sea, and West Africa off the Atlantic. They live in temperatures 24-28°C (75 – 82°F). Their diet is mainly zooplankton and brine shrimp. The Cephea cephea has specifically been known to occasionally drift inshore but in most cases is oceanic.
Reproduction
The genus reproduces frequently by the budding of the scyphistoma. The scyphistoma is the sessile polyp stage of a jellyfish. The strobilation of Cephea is monodisc, it produces only one medusa from each scyphistoma polyp. Strobilation is asexual reproduction (as in various coelenterates and tapeworms) by transverse division of the body into segments which develop into separate individuals, zooids, or proglottids. Scyphozoan medusae release planula larvae following the summer feeding period (May–August) and, although some medusae may overwinter, the medusa generally dies in the autumn (Russell, 1970).
Predators and Threats
There are records of sea turtles preying upon jellyfish within the genus Cephea.
They are also commonly and historically eaten as a delicacy or for medicinal purposes in China and Japan, along with multiple other species from its order. Cephea are targeted by the jellyfish fishing industry, especially during large blooms as well.
Jellyfish Blooms and Effects of Climate Change
Though climate change is known to be a threat to marine cnidarians such as the corals for example coral bleaching, for the jellies within that phylum it may be beneficial in increasing their population. The combination of climate change and overfishing has been linked to an increase in population or “blooms” of scyphozoans. Jellyfish blooms are known as a group of jellyfish that live together. Not all species participate in such living conditions and for the species that do, it tends to be seasonal and used as a tactic for survival. Recent studies have correlated fluctuations in jellyfish abundances and blooms with climatic changes (Holst 2012). A study conducted by Edwin Cruz-Rivera and Mohamed Abu El-Regal recorded a bloom of the Cephea cephea in the Red Sea in 2011. This phenomenon for this species was the second to be observed since the 1800s. In the article,the author mentions that for “large gelatinous zooplankton” blooms are increasing in frequency worldwide as a result of climate change. They also mention the negative effects the increase of blooms are creating. In addition to changing the structure and dynamics of open water food webs, blooming species can clog the intakes of cooling systems in power plants, obstruct fishing nets, and reduce stocks of commercially important fishes by feeding on eggs and larvae (Purcell et al. 2007; Dong et al. 2010).
Eating Jellyfish and Medicinal Purposes
The increase in jellyfish population like said previously does have some negative effects on the environment s Cephea cephea is an edible species that is harvested in Southeast Asia (Omori and Nakano 2001).
Works cited
http://www.exoticaquaculture.com/crown-jellyfish/
http://eol.org/pages/203419/details
https://www.montereybayaquarium.org/animal-guide/invertebrates/crown-jelly
http://www.marinespecies.org/aphia.php?p=taxdetails&id=213582
http://species-identification.org/species.php?species_group=zsao&menuentry=groepen&id=572&tab=refs
http://dryades.units.it/jelly/index.php?procedure=taxon_page&id=&num=117
https://biotaxa.org/cl/article/download/11.1.1551/11557
https://en.m.wikipedia.org/wiki/Rhopalium
http://thescyphozoan.ucmerced.edu/Biol/Anat/Rhopalia.html
https://www.britannica.com/science/scyphistoma
https://www.merriam-webster.com/dictionary/ring%20canal
https://www.merriam-webster.com/dictionary/strobilation
https://link-springer-com.aurarialibrary.idm.oclc.org/article/10.1007%2Fs10750-012-1043-y
https://link-springer-com.aurarialibrary.idm.oclc.org/article/10.1007%2Fs12526-015-0381-1