Blacknose shark

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Blacknose shark
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Carcharhiniformes
Family: Carcharhinidae
Genus: Carcharhinus
Species: C. acronotus
Binomial name
Carcharhinus acronotus
Range of the Blacknose shark

The Blacknose shark (Carcharhinus acronotus) is a species of requiem shark, in the genus Carcharhinus. Found along the eastern coast of the Americas, this species is found mainly in coastal waters over beds of seagrass, sandy flats, and shell or coral rubble. The Blacknose shark is quite a small species of shark, with adults reaching a maximum length of 4.6 feet (1.4 metres). This shark gets it's name from the black spot on the tip of it's snout.

Description[change | change source]

The black spot on the tip of the Blacknose shark's snout is what gives the shark it's name

Blacknose sharks are quite small and slender with a long rounded snout and large eyes. This shark gets it's name from the black spot under the tip of the snout. The Blacknose shark has two dorsal fins. The first dorsal fin is located over the free margins of the pectoral fins, and the second dorsal fin is over or slightly infront of the anal fin. The margin of the anal fin is deeply notched. This species does not have an interdorsal ridge (ridge between dorsal fins), and the caudal peduncle doesn't have a keel. The Blacknose shark is grey to greenish grey with black tips on the second dorsal fin and dorsal caudal lobe. The black spot under the tip of the snout makes this shark easy to differ from other shark species which are found in the same region. The upper jaw of the Blacknose shark has 12-13 rows of teeth on each side with 11-12 rows on the lower jaw. Teeth on the upper jaw are quite narrow and triangular with slanting cusps along with rough serrations along the bases than the tips. The lower jaw also has cusped serrated teeth with broad bases. There is one symphysial tooth in the upper jaw and one or two in the lower jaw. The average length of a full-grown Blacknose shark is around 4.1 feet (1.2 metres), reaching a maximum size of 4.6 feet (1.4 metres). This shark usually weighs about 22 pounds (10 kg) at maturity. The Blacknose shark is quite a fast growing species, with both males and females reaching maturity at the lengths of about 1 metre. [1]

Habitat[change | change source]

The Blacknose shark is found in the continental and insular shelves off the eastern coast of the Americas, as far north as North Carolina and as far south as southern Brazil, including the Bahamas, the Gulf of Mexico, and the Caribbean Sea. They around found mainly in coastal waters over beds of seagrass, sandy flats, and shell or coral rubble.[2] This species is found in different areas depending on the size and gender. Usually, only young sharks are encountered in shallow water, as the adults like depths greater than 9 metres (30 feet) and is most common at 18-64 metres (59-210 feet). [1] Blacknose sharks found off the Atlantic coast of the southern United States migrate northward in the summer and southward in the winter; a similar migration occurs for the Blacknose sharks in the Gulf of Mexico.[3]

Reproduction[change | change source]

Blacknose sharks are viviparous [4], and mate in late May and early June and have a 10-11 month gestation period. Currently, Blacknose sharks seem to have two different reproductive cycles in the Northwestern Atlantic and Gulf of Mexico. Studies have shown that female Blacknose sharks in the Gulf of Mexico reproduce every year, while females in the Atlantic reproduce once every two years. One litter of Blacknose sharks can contain 3-6 pups, but the usual number is 4. At birth, the young measure 43-51 cm in length. Both genders mature at about 2 years of age. Bulls Bay, South Carolina, United States is one known nursery area for this species.[1]

Feeding[change | change source]

The Blacknose shark is a quick swimmer, feeding on small fish including pinfish, croakers, porgies, anchovies, spiny boxfish, and porcupine fish. It is also known to feed on octopus.[1]

Human interaction[change | change source]

Blacknose sharks are of small commerical fishery importance, however it is fished as a gamefish, for the decent fight it gives when caught on light tackle. When it is harvested, this shark is often dried before being marketed for human consumption. This shark poses little threat to humans and has never been reported in a shark attack case. However, when confronted by divers, the Blacknose shark has been reported to give a threat display in the form of a hunched back with head raised and caudal lowered. [1]

References[change | change source]

  1. 1.0 1.1 1.2 1.3 1.4 "FLMNH Ichthyology Department:Blacknose shark". flmnh.ufl.edu. http://www.flmnh.ufl.edu/fish/Gallery/Descript/BlacknoseShark/blacknoseshark.html. Retrieved 24 June 2013.
  2. Stafford-Deitsch, J. (2000). Sharks of Florida, the Bahamas, the Caribbean and the Gulf of Mexico. Trident Press. p. 68. ISBN 1-900724-45-6.
  3. Driggers, W.B. (III), Ingram G.W., (Jr.), Grace, M.A., Carlson, J.K., Ulrich, J.F., Sulikowski, J.A. and Quattro, J.M. (2007). Life history and population genetics of blacknose sharks, Carcharhinus acronotus, in the South Atlantic Bight and the northern Gulf of Mexico. Small Coastal Shark Data Workshop Document, SEDAR-13-DW-17.
  4. "Blacknose Shark Pictures-Facts Carcharhinus acronotus". seapics.com. http://seapics.com/feature-subject/sharks/blacknose-shark-pictures.html. Retrieved 24 June 2013.