lion's mane jellyfish

:	Animalia
:	Cnidaria
:	Scyphozoa
:	Semaeostomeae
:	Cyaneidae
:	*Cyanea*
:	*capillata*

Binomial name

Cyanea capillata

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 and Pacific Ocean, seldom found farther south than Washington state. Similar species (which may be one and the same—see below) are known from the North and Irish Seas and from the coast of Australia. 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. The taxonomy of Cyanea species is not agreed upon: there is suggestion that all species within the genus should be treated as one.

Physical description

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 (19.7 inches) in diameter. Tentacles of larger specimens may trail as long as 30.5 metres (100 feet) or more. These extremely sticky tentacles are grouped into eight clusters—each containing ca. 150 tentacles—and are 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.

Ecology

A coldwater species, this jellyfish cannot cope with warmer waters: it is rarely seen farther south than Washington state. 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, and Moon Jellies.

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.