Lion's Mane Jellyfish

Pelagic near surface, in polar and temperate coastal waters.

Depth Range: Pelagic

This Scyphomedusa has a saucer-shaped bell up to 2 m in diameter at high latitudes; more southern specimens such as those near Rosario are usually closer to 50 cm. The bell has a thick center and a thinner margin. The margin is divided into 8 pairs of thick lobes. Has 8 clusters of up to 150 highly extensible tentacles arranged in several rows, arising from horseshoe shaped regions between the lobes. Has 8 rhopalia, each of which is situated between the two lobes of a pair. Oral arms highly folded, forming a blocky mass only about as long as the bell is wide. Color deep brick red to purplish, rose, violet, or even milky white. Yellowish-brown in small specimens, often more red in large individuals. The swimming medusa looks like an 8 pointed star at the end of its power stroke. The tentacles may trail down as far as 9 m in large specimens, 2 m in the 50 cm individuals found in our area.

How to Distinguish from Similar Species: Phacellophora camtschatica also has 16 large marginal lobes, but they are not in pairs and between these are 16 smaller lobes resembling fish tails on which the rhopalia are found. The tentacles are in 16 linear groups of up to 25 tentacles per group, hanging from the subumbrella. It is usually a lighter yellow color than is Cyanea capillata.

Biology/Natural History: Probably lives less than one year. This species can give a painful sting with blisters that lasts for several hours. It is the most likely jellyfish in our area to sting you, and may even trigger allergic shock. Feeds on small fish and crustaceans. Several symbionts may be found on the bell, including juvenile pollock and other fish, and decapod megalops larvae. The gonads of this species are 4 highly folded, ribbonlike structures that hang down under the bell and alternate with the 4 oral lobes. This is the world's largest jellyfish.

Geographical Range: Arctic and north boreal. In the Pacific it is common as far south as Washington, occasionally seen in Oregon, and probably not as far south as California. In the Atlantic it can be found as far south as Florida and Mexico.