Crown jellyfish
| Crown jellyfish | ||||||||||||
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Crowned jellyfish ( Periphylla periphylla ) |
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| Scientific name | ||||||||||||
| Periphylla periphylla | ||||||||||||
| Peron & Lesueur , 1809 |
The crown jellyfish ( Periphylla periphylla ) is a bright, red-colored deep-sea jellyfish. It belongs to the tribe of the cnidarians (Cnidaria).
Propagation cycle
P. peripyhlla is an exception that occurs very rarely in the cnidarians. The medusa does not have a polyp stage and has a "holopelagic" life cycle. The medusa releases fertilized eggs into the open water and these develop directly into the medusa, whereby the development of the medusa is based solely on the high yolk supply of the egg. The stage of the Ephyra larva that is released into the open water cannot be observed in P. periphylla .
Way of life
The jellyfish is found at depths of up to 7,000 meters and is perfectly adapted to its dark environment. By using bioluminescence , it glows from within. The light signals are used by the jellyfish to communicate with one another. A weight of up to a ton weighs on every square centimeter of the animals that live in the deep sea. At night the crown jellyfish leaves the deep sea and swims towards its food, the plankton. She returns from the surface to the deep sea with a full stomach. Other deep-sea inhabitants feed on the excretions of the crown jellyfish. The bright red crowned jellyfish can reach a body size of up to 30 centimeters. It consists of 90% water, the rest are tissue and gelatinous mass that give the animals their shape. Tiny sensory bulbs sit between their wing lobes. They allow the crown jellyfish to distinguish between light and dark. It occurs in the fjords of Norway and in the Mediterranean .
Current ecological problems
The crown jellyfish has been spreading increasingly in many fjords in Norway since the 1970s. The crown jellyfish has also spread not far from Bergen, in the Lurefjord . It is increasingly becoming a food competitor for fish and is therefore also a threat to the fishing industry. By displacing almost all other sea creatures, this jellyfish should actually have robbed itself of its own food base, but the medusa swarms continue to live. The cause is currently being investigated by marine biologists working with Ulf Bamsted. The aim is to find a possible explanation for the newer mass developments. The ecology and population dynamics are examined by Norwegian and American working groups. The ontogeny , especially the development of pigmentation, the lighting, the food intake and sensory abilities is explored in a Hamburg working group.
literature
- G. Jarms, H. Tiemann, U. Baamstedt: Development and Biology of Periphylla periphylla (Peron & Lesueur, 1809) (Scyphozoa, Coronatae) in a Norwegian Fjord. In: Marine Biology. Volume 141, No. 4, 2002, pp. 647-657.