Argentine angel shark
| Argentine angel shark | ||||||||||||
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| Scientific name | ||||||||||||
| Squatina argentina | ||||||||||||
| ( Marini , 1930) |
The Argentine angel shark ( Squatina argentina ) is a ground-dwelling shark that is found on the Atlantic coast of southern South America.
Appearance and characteristics
The Argentine angel shark can reach a maximum body length of about 140 centimeters (longer specimens up to 170 centimeters are named, but doubtful). 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. Argentine angel sharks have two dorsal fins and no anal fin . The back is purple-brown with numerous dark spots, which are usually laid out in rings around a larger dark spot; bright spots are missing. The dorsal fins are slightly lighter than the back. On the snout area there are enlarged thorns running over the mouth.
The eyes are on the top of the head, the mouth is terminal, the outer nostrils are provided with short barbels . The injection holes are large, the number of lateral gill openings is five. The nasal flaps are slightly fingered or have smooth edges.
distribution
The distribution area of the Argentine angel shark is in the coastal area of the southern Atlantic from the Rio Grande do Sul in Brazil via Uruguay to northern Patagonia in Argentina .
It lives in the outer peripheral area of the continental shelf mainly at depths between 50 and 320 meters, mostly below 120 meters.
Way of life
Little data is available on the way of life of the Argentine angel shark. Like other angel sharks, it probably feeds mainly on small bony fish, cephalopods 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 womb before the young are born alive. The females of this species give birth to seven to eleven young animals.
The animals reach sexual maturity with a body length of about 120 centimeters.
Danger
The International Union for Conservation of Nature (IUCN) classifies this shark as endangered (“Endangered”) after it was not classified until 2006 due to insufficient data (“Data deficient”). The classification was made on the basis of the comparatively low reproduction rate and the risk of overfishing that comes from the use of ground and trawl nets in the range of the species. Angel sharks are heavily fished in southern Brazil in particular, and a sharp decline has been recorded here in particular: The peak of angel shark fishing (also affects the Guggenheim angel shark ( S. guggenheim ) and the spotted angel shark ( S. punctata )) was between 1986 and 1989 and 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 .
supporting documents
- ↑ a b 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