Root mouth jellyfish
| Root mouth jellyfish | ||||||||||||
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Root mouth jellyfish ( Rhizostoma octopus ) |
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| Rhizostoma octopus | ||||||||||||
| Mayer , 1910 |
The root-mouth jellyfish ( Rhizostoma octopus ), also called cauliflower jellyfish , is a species of jellyfish from the genus Rhizostoma in the family of Rhizostomatidae .
features
The entire body of the root mouth jellyfish is of a fairly firm consistency. The umbrella can reach an average diameter of 50 cm, in rare cases up to 90 cm, making it one of the largest jellyfish. At the top of the otherwise white to cream-colored umbrella, it is tinted bluish, the 96 lobes along the edge of the umbrella are dark blue to purple in color. There are nettle cells on the umbrella , but they are slightly toxic, so that they can hardly irritate the human skin when touched; In individual cases, however, contact can be very unpleasant. As the epithet octopus suggests, the root-mouth jellyfish has eight tentacles on its body , but they are missing on the umbrella. The tentacles, which are as long as the umbrella diameter, have grown together up to the feather-like tether. The feather bands are curled like cauliflower , hence the name cauliflower jellyfish . The female sex cells are yellow to brown to red, the male blue.
The root-mouth jellyfish can swim very quickly.
Occurrence
The root mouth jellyfish is pelagic . While they reside in deeper waters in winter, they can be found closer to the Atlantic coasts and in the English Channel in summer , as they reproduce in shallower seas. Since they develop very large sex bells, they are often washed up on the beach and perish there.
They often reach the North Sea with the current . They are also found less often in the Mediterranean.
nutrition
The root mouth jellyfish feed on plankton . With the ruffled feather bands on the tentacles, they filter it from the stream of water that is pressed out of the umbrella as it moves.
Reproduction
After fertilization in summer to early autumn, the root-mouth jellyfish migrate back to deeper ocean waters. In spring they tie off umbrellas from which young jellyfish develop. These swim around in plankton-rich water and grow quickly. They overwinter on the seabed.
Others
The clear jellyfish shrimp ( Hyperia galba ), which feeds on the carcass , is often found among the root-mouth jellyfish that wash up in summer .
Importance to humans
The Rhizostoma pulmo is occasionally caught by fishermen in Turkey in the eastern Mediterranean. The estimated annual yield is around 100 tons on average.
See also
literature
- Max Egon Thiel: Investigations into the origin, occurrence, growth and reproduction of Rhizostoma octopus L. Ag. in the Elbe estuary. 1966.
Individual evidence
- ↑ Glibber for Gourmets in: Frankfurter Allgemeine Sonntagszeitung of July 31, 2011, page 49
