Lion's mane jellyfish

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{{Taxobox | color = pink | name = Lion's mane jellyfish | image = lion's mane.jpg | image_width = 200px | image_caption = A lion's mane jelly capturing a ctenophore | regnum = Animalia | phylum = Cnidaria | classis = Scyphozoa | ordo = Semaeostomeae | familia = Cyaneidae | genus = Cyanea | species = C. capillata | binomial = Cyanea capillata | binomial_authority = (Linnaeus, 1758) }}

The lion's mane jellyfish (Cyanea capillata) is the largest known species of jellyfish. Its range is confined to cold, boreal waters of the Arctic, northern Atlantic and northern Pacific Oceans, seldom found farther south than 42°N latitude. Similar jellyfish (which may be the same species) are known from the seas off Australia and New Zealand.

1 Ecology
2 Behaviour and reproduction
3 See also
4 References
5 External links

The taxonomy of Cyanea species is not fully agreed; some zoologists have suggested that all species within the genus should be treated as one. Two distinct taxa however occur together in at least the eastern North Atlantic, with the blue jellyfish (Cyanea lamarckii Péron & Lesueur, 1810) differing in blue (not red) colour and smaller size (10-20 cm diameter, rarely 35 cm). Populations in the western Pacific around Japan are sometimes distinguished as Cyanea nozakii Kisinouye, 1891, or as a race, Cyanea capillata nozakii.

A common species, the lion's mane jellyfish is well known to divers for its painful, potentially fatal stings; they are highly toxic and cause severe burns.

Image:Cyanea kils.jpg Although capable of attaining a bell diameter of 2.5 metres (8 feet), these jellyfish are highly variable in size; those found in lower latitudes are much smaller than their far northern counterparts with bells about 50 centimetres (20 inches) in diameter. The tentacles of larger specimens may trail as long as 30 metres (100 feet) or more. These extremely sticky tentacles are grouped into eight clusters, each cluster containing 65-150 tentacles, arranged in a series of rows.

The bell is divided into eight lobes, giving it the appearance of an eight-pointed star. An ostensibly tangled arrangement of colourful arms emanates from the centre of the bell, much shorter than the silvery, thin tentacles which emanate from the bell's margin.

Size also dictates coloration: larger specimens are a vivid crimson to dark purple while smaller specimens grade to a lighter orange or tan. These jellyfish are understandably named for their showy, trailing tentacles redolent of a lion's mane.

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Ecology

A coldwater species, this jellyfish cannot cope with warmer waters. The jellyfish are pelagic for most of their lives but tend to settle in shallow, sheltered bays towards the end of their one-year lifespan. In the open ocean, lion's mane jellyfish act as floating oases for certain species, such as shrimp, medusafish, butterfish, harvestfish and juvenile prowfish, providing both a reliable source of food and protection from predators.

Predators of the lion's mane jellyfish include seabirds, larger fish, other jellyfish species and sea turtles. The jellies themselves feed mostly on zooplankton, small fish, ctenophores, and moon jellies.

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Behaviour and reproduction

Lion's mane jellyfish remain mostly very near the surface at no more than 20 metres depth, their slow pulsations weakly driving them forwards; they depend on ocean currents whereby the jellies travel great distances. The jellyfish are most often spotted during the late summer and fall, when they have grown to a large size and the currents begin to sweep them closer to shore.

These jellyfish are capable of both sexual reproduction in the medusa stage and asexual reproduction in the polyp stage.

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