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Carcharhinus acronotus

(blacknose shark)

Overview

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Family : Requiem sharks ; Found on continental and insular shelves, mainly over sandy, shell , and coral bottoms . Feeds on small fishes , including pinfish (Sparidae) and porcupine fish. Preyed on by larger sharks . Viviparous (with a yolk-sac placenta ), with 3 to 6 young per litter . Performs a 'hunch' display, with back arched, caudal lowered and head raised, as a possible threat display when confronted by divers . Utilized dried salted for human consumption .

Near Threatened

Threat status

Interesting Facts

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Common Names

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Click on the language to view common names.

Common Names in Czech:

Žralok tmavonosý, Žralok tmavonosý

Common Names in Danish:

Sortn, Sortnæset haj

Common Names in Dutch:

Zwartsnuithaai

Common Names in English:

blacknose shark

Common Names in Finnish:

Sarda

Common Names in French:

Requin nez noir

Common Names in Japanese:

Hanagurozame

Common Names in Mandarin Chinese:

黑吻真鯊, 黑吻真鲨

Common Names in Portuguese:

Ca, Cação, Cação-lombo-preto, Corta-garoupa, Lombo-preto

Common Names in Russian:

акула черноносая

Common Names in Spanish:

Caz, Cazón, Cazon amarillo, Sarda, Tibur, tiburón cangüay, tiburón limón, Tiburón amarillo, tiburón cangüay, Tiburón hocico negro, Tiburón limón, Tiburón tollo, Tollo

Description

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Physical Description

Species Carcharhinus acronotus

Distinctive Features: Blacknose sharks are relatively small and slender with a somewhat long rounded snout and large eyes. This shark gets its common name from the characteristic black or dusky spot under the tip of the snout. The origin of the first dorsal fin is located over the free margins of the pectoral fins; the origin of the second dorsal fin is over or slightly anterior of anal fin origin . The margin of the anal fin is deeply notched . The interdorsal ridge (ridge between dorsal fins) is absent in this species and the caudal peduncle lacks a keel.

Coloration : The blacknose shark is gray to greenish gray with black or dusky tips on the second dorsal fin and dorsal caudal lobe . There is a black or dusky spot under the tip of the snout which is more distinct in younger individuals, hence the common name "blacknose shark". This spot makes this shark easy to distinguish from other gray shark species that occur in the same region.

Dentition: 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 moderately narrow and triangular with oblique cusps along with coarser 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.

Denticles : Dermal denticles of the blacknose shark are closely spaced and overlapping. Each denticle has three longitudinal ridges and three posterior marginal teeth in embryos and young individuals while subadults and adults have denticles with 5 or 7 longitudinal ridges and 3-5 posterior marginal teeth.

Size, Age, and Growth: The average length of a full-grown blacknose shark is approximately 4.1 feet (125 cm TL ), reaching a maximum size of 4.6 feet (140cm TL). Depending on geographic location, maximum age is 10-16 years for females and 4.5-9 years for males. This shark commonly weighs about 22 pounds (10 kg ) at maturity. A relatively fast growing species, males reach maturity at 3-3.5 feet (95-105 cm), while females reach maturity at lengths between 3.3-3.5 feet (100 and 105 cm). Both sexes mature at about 2 years of age.

Habitat

This shark is found in coastal tropical and warm temperate waters of the western Atlantic Ocean. As an inshore species, the blacknose shark resides in waters of continental shelves over sandy and coral bottoms . There is segregation by size and sex in this species. Juveniles are typically found in shallow water while adults are located at greater depths (over 30 feet (9 m )). This shark is known to form large schools and sometimes associates with schools of mullet and anchovies .

Typically found in water with a depth of 0 to -457 meters (0 to -1,499 feet).[1]

Ecology: A common coastal tropical and warm-temperate shark of the continental and insular shelves, mainly over sandy, shell and coral bottom , depths of 18?64 m (Compagno et al. 2005).

The species may possibly reach 200 cm total length (TL ) (Compagno et al. 2005). Depending on the area, size at maturity is between 84.8 and 100.5cm Fork Length (FL ) for females and 84.8?91.8 cm (FL) for males (Clark and von Schmidt 1965, Dodrill 1977, Schwartz 1984, Driggers et al. 2004, Sulikowski et al. 2007, Carlson et al. in press ), In US South Atlantic waters males are reported to reach maturity at 4.3 years and females at 4.5 years of age (Driggers et al. 2004). Whereas in the Gulf of Mexico, males reportedly mature at 5.4 years and females at 6.6 years of age (Carlson et al. 2007). Longevity is estimated as 19 years in US South Atlantic waters and 16.5 years in the Gulf of Mexico, for females (Driggers et al. 2004, Carlson et al. 1999, Sulikowski et al. 2007). Generation period is estimated at eight years (Siegfreid and Brooks 2007) Reproduction is viviparous with a yolk-sac placenta . The species has a biennial reproductive cycle in US South Atlantic waters, but an annual cycle is reported in the Gulf of Mexico and off northern Brazil (Driggers et al. 2004, Sulikowski et al. 2007, Hazin et al. 2002). Females give birth to 1?5 pups after a gestation period of 9?11 months (Driggers et al. 2004, Carlson et al. 1999, Sulikowski et al. 2007). Size at birth is 31?35 cm FL (Driggers et al. 2004). [2].

List of Habitats :

Biology

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Diet

The blacknose shark is a quick swimmer, feeding on small fishes including pinfish, croakers, porgies , anchovies , spiny boxfishes , and porcupine fish. It is also known to feed on octopus .

Reproduction

Vitellogenesis (development of yolk ) and gestation occur consecutively in the blacknose shark . This means that the ovaries ripen and develop yolk in the few months prior to mating. The blacknose shark mates in the fall and gives birth spring-summer, having a gestation period of about 8 months. The length of the periods of vitellogenesis and gestation together is about 10-11 months. It is not yet certain whether the entire reproductive cycle is annual or whether there is an extended resting period between pregnancies.

Litter size for the blacknose shark is 3-6, but the usual number is 4. At birth, the young measure 17-20" (43-51 cm) in length. Bulls Bay , South Carolina (U.S.) is one known nursery area for this species.

Behavior

Predators : Blacknose sharks may fall prey to larger sharks, including the dusky shark (Carcharhinus obscurus).

Taxonomy

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Synonyms

Carcharhinus acronotus • Prionodon curcuri Castelnau • Squalus acronotus • Squalus acronotus Poey • Squalus acronotus Poey, 1860

Notes

Name Status: Accepted Name .

First described: Poey, F. Memorias sobre la historia natural de la isla de Cuba, acompañadas de sumarios latinos y extractos en francés. Vol. II. Imprenta de Barcina, Habana, Cuba., 1860.

Last scrutiny: Data last modified by FishBase 28-Oct-2000

Similar Species

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Members of the genus Carcharhinus

ZipcodeZoo has pages for 36 species and subspecies in this genus:

C. acronotus (Blacknose Shark) · C. ahenea (Shortnose Blacktail Shark) · C. albimarginatus (Silvertip Shark) · C. altimus (Knopp´s Shark) · C. amblyrhynchoides (Graceful Shark) · C. amblyrhynchos (Shortnose Blacktail Shark) · C. amboinensis (Ambon Sharpnose Puffer) · C. azureus (Large Blacktip Shark) · C. borneensis (Borneo Mullet) · C. brachyurus (Black-Tipped Whaler) · C. brevipinna (Blacktipped Shark) · C. cautus (Sharks Bay Whaler Shark) · C. dussumieri (Whitecheek Shark) · C. falciformis (Sickle-Shaped Shark) · C. fitzroyensis (Creek Whaler Shark) · C. galapagensis (Galapagos Shark) · C. hemiodon (Pondicherry Shark) · C. isodon (Fintooth Shark) · C. leiodon (Smoothtooth Blacktip Shark) · C. leucas (Bull Shark) · C. limbatus (Blacktip Shark) · C. longimanus (Brown Milbert's Sand Bar Shark) · C. macloti (Hardnose Shark) · C. melanopterus (Black Fin Reef Shark) · C. obscurus (Dusky Shark) · C. perezi (Caribbean Reef Shark) · C. perezii (Caribbean Reef Shark) · C. plumbeus (Northern Whaler Shark) · C. porosus (Tiburon Peninsula Limia) · C. sealei (Black-Spot Shark) · C. signatus (Night Shark) · C. sorrah (West Australian Whaler Shark) · C. springeri (Reef Shark) · C. tilstoni (Australian Blacktip Shark) · C. velox (Whitenose Shark) · C. wheeleri (Blacktail Reef Shark)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal March 01, 2008:

Identifiers

Footnotes

  1. Mean = -58.000 meters (-190.289 feet), Standard Deviation = 141.170 based on 10 observations. Ocean depth information for each observation from British Oceanographic Data Centre. [back]
  2. Morgan, M., Carlson, J., Kyne, P.M. & Lessa, R. 2009. Carcharhinus acronotus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 31 January 2012. [back]
Last Revised: 7/15/2012