Nervous shark
| Nervous shark | ||||||||||||
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Nervous shark ( Carcharhinus cautus ) |
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| Scientific name | ||||||||||||
| Carcharhinus cautus | ||||||||||||
| ( Whitley , 1945) |
The nervous shark ( Carcharhinus cautus ) is a species of the genus Carcharhinus within the Requiem sharks (Carcharhinidae). The species is found in the waters around Australia , Papua New Guinea and the Solomon Islands . Its name is derived from the shark's fearfulness towards swimmers and divers.
Appearance and characteristics
The nervous shark is a medium-sized shark with a maximum body length of about 150 cm and average lengths between 100 and 130 cm. He has a gray-brown to bronze-colored body color, a clear white band on the flanks and a whitish belly region without pattern. The dorsal and pectoral fins as well as the caudal fin have a black border, which ends at the caudal fin and the pectoral fins to a black fin tip.
It has an anal fin and two dorsal fins . The first dorsal fin is high and sickle-shaped and lies slightly in front of or over the free ends of the pectoral fins. The second dorsal fin is also relatively high with a height of 3–4% of the body length of the animal. Like all species of the genus, the animals have five gill slits and no injection hole .
The nervous shark resembles other species of the genus Carcharhinus in habit , especially with the blacktip reef shark ( Carcharhinus melanopterus ). However, this also has noticeable black fin tips on the anal fins and the dorsal fin.
Way of life
The nervous shark is a shallow water species and predatorily feeds on various fish from the shore zones, and to a lesser extent it also hunts crustaceans and squid . The sharks are viviparous and form a yolk sac placenta ( placental viviparous ). After a gestation period of 8 to 9 months, the females have between one and 5 young animals with a length of about 35 to 40 cm in one litter.
distribution
The nervous shark is common in the eastern Indian Ocean and the South Pacific in tropical waters in the area between latitudes 5 ° S and 30 ° S around Australia ( Queensland , Western Australia ), Papua New Guinea and the Solomon Islands . It occurs mainly in shallow waters above the continental shelf and possibly also in deeper waters.
Importance to humans
The nervous shark is generally classified as harmless, as a rule it avoids encounters with swimmers and divers. It is caught and eaten in small numbers, an estimate of the total number of catches or the influence on the population does not exist.
literature
- Kuno Sch. Steuben : The sharks of the seven seas: species, way of life and sporting catch. Parey, Berlin 1989; Pages 85 and 98. ISBN 3-490-44314-4
Web links
- Species portrait on hai.ch
- Nervous Shark on Fishbase.org (English)
- Carcharhinus cautus inthe IUCN 2013 Red List of Threatened Species . Posted by: Bennett, MB & Kyne, PM (SSG Australia & Oceania Regional Workshop, March 2003), 2003. Retrieved December 4, 2013.