Biodiversity & Conservation

Lion's mane jellyfish - Cyanea capillata

Cyanea capillata

Image Tim Nicholson - Cyanea capillata at the Isle of Man. Image width ca 1.2 m in foreground.
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Distribution map

Cyanea capillata recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

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Cyanea capillata is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Cnidaria Sea anemones, corals, sea firs & jellyfish
Authority (Linneaus, 1758)
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Found around the coasts of the British Isles, most commonly along the east coast of England and Scotland. Also common in the Irish Sea.
Habitat information icon Habitat information Cyanea capillata is pelagic species that can be found washed up on beaches.
Text page icon Description Cyanea capillata is one of the largest species of jellyfish and is commonly referred to as Lions mane jellyfish due to the highly distinguishable mass of long, thin, hair-like tentacles. Cyanea capillata has a saucer-shaped bell (the umbrella) with a uniform thickness until thinning dramatically around the edges. Usually yellowish brown or reddish in colour. It generally grows to 30-50 cm in diameter in British waters. However, they have been known to grow up to 200 cm. The margin of the bell bears hollow tentacles, arranged in eight groups with 70 to 150 or more tentacles in each. The mouth and oral arms stem from a projection on the underside of the umbrella (the manubrium). The oral arms are thick, frilled, folded and generally as long as the diameter of the umbrella.
Identifying features
  • Cyanea capillata has a diameter 30 cm or more.
  • Usually yellow brown or red in colour.
  • It is easily distinguished by a mass of long, hair-like tentacles.
  • There at least 65 tentacles in each of the eight groups of tentacles.
Additional information icon Additional information Young Cyanea capillata may be found as early as February in British waters, although the main period of abundance for larger individuals is June to September. This species does occasionally occur in large swarms, largely thought to be due to storms and tides that concentrate individuals together (Russell, 1970). They have a very severe sting that can produce blisters, irritation, and muscular cramp and may even affect respiratory and heart function. Cyanea capillata can still sting long after being stranded on the shore.

This review can be cited as follows:

Jessica Heard 2005. Cyanea capillata. Lion's mane jellyfish. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 18/06/2013]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3109>