Guggenheim angel shark
| Guggenheim angel shark | ||||||||||||
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| Systematics | ||||||||||||
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| Squatina guggenheim | ||||||||||||
| Marini , 1930 |
The Guggenheim angel shark ( Squatina guggenheim , Syn . : S. occulta ) is a ground-dwelling shark that occurs on the Atlantic coast of southern South America.
Appearance and characteristics
The Guggenheim angel shark can reach a maximum body length of about 130 cm. As with other angel sharks, the body is strongly flattened with very broad pectoral fins , which makes the animals look more like long rays in shape . However, the pectoral fins are clearly separated from the trunk, while in most rays they merge seamlessly into the body. They have two dorsal fins and no anal fin . The body has an evenly brown back color with numerous small yellow spots and larger black markings. There are also some eye spots on the pectoral fins . On the muzzle area, in the area of the eyes and the injection holes there are some slightly enlarged thorns that stand in groups; Back spikes are not available.
The eyes are on the top of the head, the mouth is terminal, the outer nostrils are provided with short barbels with a cylindrical base. The injection holes are large, the number of lateral gill openings is five. The nasal flaps are only slightly fingered or have smooth edges.
distribution
The distribution area of the Guggenheim angel shark is in the coastal area of the southern Atlantic from Brazil to Uruguay . It lives in the outer peripheral area of the continental shelf mainly at depths between 35 and 115 meters, mostly above 100 meters.
Way of life
Little data is available on the way of life of the Guggenheim angel shark. Like other angel sharks, it feeds mainly on small bony fish and crustaceans , which it prey on lying on the ground as a lurker . Like all angel sharks, it is ovoviviparous - the eggs are hatched in the mother before the young are born alive. The females of this species give birth to six to eight young animals in spring, the gestation period is eleven months.
The animals reach sexual maturity with a body length of about 110 centimeters.
Danger
The International Union for Conservation of Nature (IUCN) classifies this shark as endangered ("Endangered"). As with other species on the South American coast, the classification was based on the comparatively low reproduction rate and the risk of overfishing caused by the use of ground and trawl nets in the range of the species. Angel sharks are fished heavily in southern Brazil in particular, and a sharp decline has been recorded here in particular: The peak of angel shark fishing (also affects the Argentine angel shark ( Squatina argentina ) and the spotted angel shark ( S. punctata )) was between 1986 and 1989 and in In 1993 at around 2,000 tons per year before falling to 900 tons by 2003. In addition, the shark is a common bycatch species in commercial fisheries, which primarily aim to catch the anglerfish species Lophius gastrophysus . Research catches from 1986/87 and 2001/02 could show that the stocks of the Guggenheim angel shark have decreased by 85%. In addition, the sharks seem to get their young in special shallow water areas below 30 meters deep, where the fishing pressure is particularly high.
supporting documents
- ↑ a b Squatina guggenheim in the endangered Red List species the IUCN 2010. Posted by: Chiaramonte, G. & Vooren, CM, 2007. Retrieved on December 18 of 2010.
- ↑ Squatina argentina in the endangered Red List species the IUCN 2010. Posted by: Vooren, CM & Chiaramonte, GE, 2006. Retrieved on December 18 of 2010.
literature
- Leonard Compagno , Marc Dando, Sarah Fowler: Sharks of the World . Princeton University Press , Princeton and Oxford 2005, p. 138 ISBN 978-0-691-12072-0