Swell shark
| Swell shark | ||||||||||||
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Swell shark ( Cephaloscyllium ventriosum ) |
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| Scientific name | ||||||||||||
| Cephaloscyllium ventriosum | ||||||||||||
| ( Garman , 1880) |
The swellshark ( Cephaloscyllium ventriosum ) is a kind from the family of dogfish (Scyliorhinidae) mounted on the American Pacific coast from central California ( Monterey Bay occurs) to central Chile.
features
The swell shark can reach a body length of one meter. Seen from above and below, its snout is very short and rounded. The front nostrils are wide, roughly triangular and overlap the mouth at the back. The mouth is large and has small, pointed teeth that are suitable for holding onto large prey. There are no labial furrows . The second dorsal fin is smaller than the first. The clasps are short and thick. The color of the swell shark is variable and characterized by dark brown, saddle-like spots, numerous dark and light spots on a yellowish-brown basic color. The underside is spotted. The swell shark can inflate its stomach with water (or trapped with air) so that the whole torso swells (English name).
Like many cat sharks, the swell shark also exhibits biofluorescence excited by incident light similar to bioluminescence . There are recent film recordings that show biofluorescence (spread over the whole body). Detectable only with special light.
Way of life
The swell shark lives in temperate and subtropical marine regions on the continental shelf, mostly at depths of 5 to 37 meters, up to a maximum depth of around 450 meters. It occurs mainly in rocky regions overgrown with algae or kelp . The nocturnal swell shark spends the day motionless in caves or crevices, often with several specimens, which can also lie on top of each other in the confines. At night it swims lazily and slowly across the sea floor in search of food. The swell shark feeds on live or dead fish, probably also on various crustaceans. Since it is unlikely to be able to actively hunt for moving prey, it is believed that it mainly catches diurnal bony fish, which sleep on the sea floor the night and are then restricted in their ability to react.
The swell shark is oviparous . The horny egg capsules are relatively large and greenish-yellow in color. Depending on the water temperature, the young sharks hatch after 7.5 to 19 months with a body length of 13 to 17 cm. A double row of teeth on the back helps the young sharks to leave the egg capsules.
Danger
The main threat to this species is accidental bycatch from commercial fishing.
literature
- Leonard JV Compagno : Sharks of the world. An annotated and illustrated catalog of shark species known to date. Part 2 - Carcharhiniformes. FAO Species Catalog. Volume 4. In: FAO Fish. Synop. Volume 125, No. 4/2, 1984, pp. 251-655, Rome: FAO.
- William N. Eschmeyer, Earl S. Herald, Howard Hamann: A field guide to Pacific Coast Fishes of North America. From the Gulf of Alaska to Baja California (Peterson Field Guides; 28). Houghton Mifflin, Boston (Mass.) 1983, ISBN 0-395-33188-9 .
Web links
- Cephaloscyllium ventriosum on Fishbase.org (English)
Individual evidence
- ↑ David F. Gruber, Ellis R. Loew, Dimitri D. Deheyn, Derya Akkaynak, Jean P. Gaffney, W. Leo Smith, Matthew P. Davis, Jennifer H. Stern, Vincent A. Pieribone, John S. Sparks: Biofluorescence in catsharks (Scyliorhinidae): Fundamental description and relevance for Elasmobranch visual ecology. In: Sci. Rep. Volume 6, 2016, p. 24751, doi : 10.1038 / srep24751 .
- ↑ TV report on ServusTV on May 25, 2016.
- ↑ Cephaloscyllium ventriosum in the IUCN Red List of Threatened Species 2013.2. Posted by: CV Garayzar, 2006. Retrieved May 20, 2014.