Bigeye six gill shark
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Bigeye six gill shark ( Hexanchus nakamurai ) |
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| Hexanchus nakamurai | ||||||||||||
| Teng , 1962 |
The bigeye six-gill shark ( Hexanchus nakamurai ) belongs to the order of the Hexanchiformes .
Appearance
The up to 1.80 meter long sharks have a gray back and a light belly. It is named after the large, green fluorescent eyes and the six gill slits, which all lie in front of the attachment of the pectoral fin and get smaller and smaller from front to back. The big-eyed six-gill shark shares this characteristic with the snub-nosed six-gill shark from the same genus, which, however, is much larger and has significantly smaller eyes. The small dorsal fin sits far back. The anal fin is smaller than the dorsal fin. All fins have light-colored edges. The muzzle is pointed. The teeth of the upper jaw are small and pointed. In the lower jaw, the teeth are comb-shaped and, after a point, have additional small peaks. They are much larger than those of the upper jaw.
distribution
The bigeye six-gill shark is widespread, but since it is rarely caught, its exact range is uncertain. In the western Pacific, catches have been reported in Japan, Taiwan, the Philippines, New Caledonia and eastern Australia. A population is also known off Madagascar and Kenya. It was found in the eastern Atlantic near Gibraltar, possibly also on the coast of Ivory Coast and Nigeria. It is also said to occur in the Mediterranean. The six gill sharks found in the tropical, western Atlantic have been considered an independent species again, Hexanchus vitulus , since February 2018 .
The big-eyed six-gill shark lives mostly at depths of 90 to 600 meters.
Way of life
The sharks live close to the ground, especially at greater depths, but in the tropics also on the surface of the sea. They likely feed on bony fish and crustaceans .
Bigeye gill sharks are ovoviviparous . They get up to 13 juveniles per litter, which are 40 centimeters long at birth. Males are sexually mature with 1.25 to 1.6 meters, females with 1.45 to 1.8 meters.
The sharks are considered harmless.
literature
- Leonard JV Compagno : Sharks of the world An annotated and illustrated catalog of shark species known to date Part 1 - Hexanchiformes to Lamniformes . FAO SPECIES CATALOG Complete PDF H. vitulus = H. nakamurai
Individual evidence
- ↑ Daly-Engel, TS, Baremore, IE, Grubbs, RD, Gulak, SJB, Graham, RT & Enzenauer, MP (2018): Resurrection of the sixgill shark Hexanchus vitulus Springer & Waller, 1969 (Hexanchiformes, Hexanchidae), with comments on its distribution in the northwest Atlantic Ocean. Marine Biodiversity, February 2018.
Web links
- www.hai.ch Broad-nosed seven-gill shark ( Hexanchus nakamurai )
- Bigeye Shark on Fishbase.org (English)
- Hexanchus nakamurai inthe IUCN 2013 Red List of Threatened Species . Posted by: Ebert, DA, Serena, F. & Mancusi, C., 2009. Retrieved September 20, 2013.