Up to 15cms in diameter, the Blue Jellyfish or Cyanea lamarkii is a common visitor to our coasts from May to October. It feeds on plankton primarily but will eat anything that sticks to its long train of stinging tentacles, including other jellyfish. To a human, the sting is less severe than a nettle sting and does not last long but this may depend on an individual's sensitivity. Belying its name, the Blue Jellyfish is sometimes pure white!
Like other jellyfish, this is an annual animal that starts out life in late Winter as a tiny animal about the size of a finger nail but as it drifts feeding in the plankton, it develops rapidly. At its peak its tentacles are probably 1m long. Once the plankton supply diminishes in late Autumn and the seas become very rough, the Blue Jellyfish dies.
North Sea - St. Abbs Marine Reserve.