About Jellyfish
Jellyfish (also jellies or sea jellies) are free-swimming members of the phylum Cnidaria. Jellyfish have several different morphologies that represent several different cnidarian classes including the Scyphozoa (over 200 species), Staurozoa (about 50 species), Cubozoa (about 20 species), and Hydrozoa (about 1000-1500 species that make jellyfish and many more that do not). The jellyfish in these groups are also called, respectively, scyphomedusae, stauromedusae, cubomedusae, and hydromedusae; medusa is another word for jellyfish, and as such is used to refer specifically to the adult stage of the life cycle.
Jellyfish are found in every ocean, from the surface to the deep sea. Some hydrozoan jellyfish, or hydromedusae, are also found in fresh water; freshwater species are less than an inch (25 mm) in diameter, are colorless and do not sting. Many of the best-known jellyfish, such as Aurelia, are scyphomedusae. These are the large, often colorful, jellyfish that are common in coastal zones worldwide.
In its broadest sense, the term jellyfish also generally refers to members of the phylum Ctenophora. Although not closely related to cnidarian jellyfish, ctenophores are also free-swimming planktonic carnivores, are generally transparent or translucent, and exist in shallow to deep portions of all the world's oceans.
Jellyfish are amongst the most spectacular marine species in the world. They can be found in all the seas and oceans of the world at every level of the water, from the surface to the very depths.
Different species thrive under different climactic conditions, and jellyfish are known to exist in the coldest waters of the Arctic Oceans to the warm temperate waters that surround Australia. Very few species are able to survive across different climactic conditions, and most species can only be found in specific locations under specific conditions.
Jellyfish are found in every ocean, from the surface to the deep sea. Some hydrozoan jellyfish, or hydromedusae, are also found in fresh water; freshwater species are less than an inch (25 mm) in diameter, are colorless and do not sting. Many of the best-known jellyfish, such as Aurelia, are scyphomedusae. These are the large, often colorful, jellyfish that are common in coastal zones worldwide.
In its broadest sense, the term jellyfish also generally refers to members of the phylum Ctenophora. Although not closely related to cnidarian jellyfish, ctenophores are also free-swimming planktonic carnivores, are generally transparent or translucent, and exist in shallow to deep portions of all the world's oceans.
Jellyfish are amongst the most spectacular marine species in the world. They can be found in all the seas and oceans of the world at every level of the water, from the surface to the very depths.
Different species thrive under different climactic conditions, and jellyfish are known to exist in the coldest waters of the Arctic Oceans to the warm temperate waters that surround Australia. Very few species are able to survive across different climactic conditions, and most species can only be found in specific locations under specific conditions.
