Corona hammerhead shark
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Corona hammerhead shark ( Sphyrna corona ) |
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| Sphyrna corona | ||||||||||||
| Springer , 1940 |
The corona hammerhead shark ( Sphyrna corona ) is the smallest shark within the family of hammerhead sharks (Sphyrnidae) with a maximum length of up to 92 centimeters . It lives along the subtropical and tropical coast of the eastern Pacific from Mexico to Peru .
features
The corona hammerhead is the smallest of the known species within the hammerheads with an average length between 60 and 70 centimeters and a maximum body length of up to 92 centimeters. The back is gray, the underside of the body white. The head or the cephalofoil is less widened than other hammerhead sharks and has a comparatively long snout. It reaches a maximum width of 2/5 of the total length of the shark. The front is arched with clear notches in the middle and at both ends. The mouth is small and strongly curved.
The first dorsal fin is slightly sickle-shaped and is arranged above the attachment of the pectoral fin, the rear edge of the anal fin is almost straight.
distribution
The corona hammerhead shark lives in the tropical waters of the Pacific Ocean from Mexico to Peru, mainly near the coast in the area of the continental shelf .
Way of life
Little data is available on the way of life of the corona hammerhead. Like other small hammerhead shark species, it probably feeds primarily on invertebrates and smaller bony fish.
Reproduction and development
Like all hammerhead sharks, this species is viviparous (ovoviviparous), whereby the unborn young sharks are fed via a yolk sac placenta . After the yolk supply has been used up by the young sharks , the yolk sac is transformed into a placenta, which functionally corresponds to that of a mammal and ensures nutrition via the maternal bloodstream in the course of further development.
As a rule, the female probably gets two young animals up to 23 centimeters in length. The corona hammerheads reach sexual maturity at a length of about 60 centimeters.
Danger
The International Union for Conservation of Nature (IUCN) classifies this shark as “Near Threatened” because it is potentially under intense fishing pressure and, due to its low reproductive rate, is very susceptible to population decline. When classifying, however, it is emphasized that the species can also be considered endangered due to its limited range and low reproduction rate, similar to the small-eyed hammerhead shark ( Sphyrna tudes ), but there are currently no data that show a decline in the population .
supporting documents
- ^ A b c Leonard Compagno, Marc Dando, Sarah Fowler: Sharks of the World. Princeton University Press, Princeton 2005; P. 323. ISBN 0-691-12072-2 .
- ↑ Sphyrna corona on Fishbase.org (English)
- ↑ a b Sphyrna corona in the endangered Red List species the IUCN 2010. Posted by: Mycock, SG (SSG South America Regional Workshop, June 2003), 2004. Accessed on 19 September, 2010.
literature
- Leonard J. V. Compagno : Sharks of the world. An annotated and illustrated catalog of shark species known to date. Part 2. Carcharhiniformes. FAO Species Catalog for Fishery Purposes. Volume 4, FAO Rome 1984; Pp. 545-554. 92-5-101383-7. ( Family Sphyrnidae Gill , 1872, species portrait )
- Leonard Compagno, Marc Dando, Sarah Fowler: Sharks of the World. Princeton University Press , Princeton 2005; P. 323. ISBN 0-691-12072-2 .
Web links
- Sphyrna corona on Fishbase.org (English)
- Sphyrna corona at the Shark Foundation