The Blacknose shark is a species of requiem shark, belonging to the family Carcharhinidae and is common in the tropical and subtropical waters of the western Atlantic Ocean. The Blacknose shark generally inhabits coastal seagrass, sand, or rubble habitats. Fully grown Blacknose sharks do prefer deeper water than juveniles. It gets its name from the black notch on the top of its snout. The Balcknose shark is not known to attack humans, though it has been documented performing a threat display towards divers.
Family: Carcharhinidae – Requiem sharks
Genus: Carcharhinus
Species: acronotus
Phylum– Chordata
Class– Chondrichthyles
Subclass– Elasmobranchii
Common Name– Ground Sharks
Family– Carcharhinidae
Common Name– Requiem Sharks
Genus– Carcharhinus
Species– acronotus
Status: IUCN Red List Near Threatened
Average Size and Length: Full-grown Blacknose sharks are typically 4.1 feet, with a maximum recorded length of 4.6 feet.
Average Weight: The average weight of an adult Blacknose shark is 23 pounds.
Teeth and Jaw: 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 somehwat narrow and triangular with oblique cusps along with harsher serrations along the bases than the tips. The lower jaw of the Blacknose shark also has cusped serrated teeth with broad bases. There is one symphysial tooth in the upper jaw and one or two usually in the lower jaw of a Blacknose shark.
Head: The large, rounded snout has a dusky blotch at the tip (juvinelles have a distinctive black spot just under the tip), earning its name. The Blacknose shark has very large eyes.
Denticles: The Blacknose shark’s dermal denticles are closely spaced and they are overlapping each other. Each denticle has three longitudinal ridges and three posterior marginal teeth in embryos and young individuals while growing sharks and adults have denticles with 5 or 7 longitudinal ridges and 3-5 posterior marginal teeth.
Demographic, Distribution, Habitat, Environment and Range: The Blacknose shark is common in tropical and sub-tropical waters of the western Atlantic Ocean; southern USA to South Brazil. Here in Jupiter, there are a common species to see. They hug the shore of Florida that turns into the Gulf hugging Texas all the way through Central America. The Blacknose shark is an in-shore species, generally inhabits coastal seagrass, brackish water, sand, or rubble habitats, with adults preferring deeper water than juveniles.
Diet: The Blacknose shark feeds on small fishes including pinfish, croakers, porgies, anchovies, spiny boxfishes, and porcupine fish. It is also known to enjoy octopus.
The Blacknose is a smaller shark and is a known to be a favorite food of the Dusky shark.
Aesthetic Identification: The Blacknose shark is small and slender. The Blacknose shark is gray to greenish gray with black or dusky tips on the second dorsal fin and dorsal caudal lobe. The first dorsal fin originates over or behind the free tips of the pectoral fins. The margin of the anal fin is deeply notched. The interdorsal ridge is absent in the Blacknose shark and the caudal peduncle lacks a keel.
Biology and Reproduction: There is segregation by size and sex of Blacknose sharks.
The maximum age of a Blacknose shark is 11.5 years for a female and 9.5 years for a male in the Gulf of Mexico. (Carlson et al. 2007)
Male Blacknose sharks reach maturity at 3-3.5 feet, while females reach maturity at lengths between 3.3-3.5 feet. Both sexes mature at about 2 years of age.
The Blacknose shark is vitellogenesis. They mate in late May/early June and have a 10-11-month gestation period. Currently, Blacknose sharks appear to exhibit 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 annually; however, female Blacknose sharks in the Atlantic appear to reproduce biennially.
Blacknose sharks have between 3-6 pups, but the usual number is 4. At birth, the young measure 17-20″ in length. Bulls Bay, South Carolina (U.S.) is one known nursery area for this species.
Behavioral Traits, Sensing and Intelligence: The Blacknose shark is known to form large schools and sometimes associates with schools of mullet and anchovies.
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.
Speed: The Balcknose shark is a speedy swimmer.
Blacknose Shark Future and Conservation: Blacknose sharks are of minor commercial fishery importance, however it is fished as a gamefish, for the decent fight it gives when caught on light tackle. Here in Florida (especially in Palm Beach and Martin County), this is a typical shark fallen victim to land-based shark fishing. As we continue to fight to ban land-based shark fishing to protect the sharks, but also to protect the local people and tourists who like to swim at our beaches, we do our best to educate the community on the conservation of this species.
When it is harvested, this shark is often dried prior to being marketed for human consumption.
Blacknose Shark Recorded Attacks on Humans: This shark poses little threat to humans and has never been reported in a shark attack case.