The Bignose shark is a species of requiem shark, in the family Carcharhinidae. It can be found worldwide in tropical and subtropical waters and is migratory. The Bignose shark frequents deep waters around the edges of the continental shelf. It is typically found at depths of 300–1,410 feet, moving closer to the surface at night. It hunts close to the sea floor and doesn’t pose a threat to humans.
Family: Carcharhinidae – Requiem sharks
Common Name– Knopp’s Shark
Status: IUCN Red List NO DATA
Average Size and Length: The Bignose shark has an average length of 8.9-9.2 feet.
Average Weight: The Bignose shark can weigh as much as 370 pounds.
Teeth and Jaw: The mouth of a Bignose shark is broadly curved without furrows at the corners.
The teeth in the upper jaw are broad, large and triangular with serrated edges (except for the first two series om each side of the symphysis (one or two small symphysial teeth). These teeth have concave lateral margins, they are straight to convex margins and both margins serrated. There are between 14 and 16 teeth on each side in the upper jaw, plus the symphysial teeth.
The lower teeth are much different. They are narrow with finely serrated margins, narrow serrated cusps, and one symphysial tooth. There are between 14 or 15 teeth in the lower jaw.
Head: The Bignose shark has a long snout, very broad and protruding nasal skin flaps. The Bignose shark has fairly large eyes that have nictitating membranes.
Denticles: The dermal denticles are closely spaced but non-overlapping. The skin can be seen between them. Each denticle is oval with three horizontal ridges leading to marginal teeth.
Demographic, Distribution, Habitat, Environment and Range:The Bignose shark can be found worldwide in tropical and subtropical water climates. It can be found worldwide, however spotty and migratory (migration habits are said to be seasonal, but not very well-documented). It is an offshore shark, typically staying just near the edges of the continental shelf. Adults can be found in deep waters ranging between 300 and 1,410 feet. At night it may move towards the surface or into shallower water, and juvenile Bignose sharks typically stay in shallower waters.
In the western Atlantic Ocean, the Bignose shark can be found from Florida all the way south to Venezuela. Some have witnessed it as north as Delaware. In the eastern Atlantic Ocean, it has been reported from Senegal to Ghana including the Mediterranean Sea. Some reports from the western Indian Ocean include the Red Sea, Mozambique, South Africa, Madagascar, and India. In the Pacific Ocean, the Bignose shark can be found off the coast of China in the west (all the way to Australia), Hawaii in the central, and Gulf of California, Mexico, Colombia, and Ecuador in the east.
The Bignose shark is common here off the coast of Florida and Bahamas, and is rare in Brazil and the Mediterranean.
Diet:The Bignose shark feeds mainly on bottom-dwelling bony fishes, such as: lizardfishes, croakers, mackerels, flatfishes, and batfishes, cartilaginous fishes, such as: dogfishes, catsharks, stingrays, and chimaeras, and cephalopods.
Larger sharks are predators of Bignose sharks, juveniles fall victim and are prey of Great White Sharks.
Aesthetic Identification: The Bignose shark has a greyish body without any markings. It is counter-shaded with a white belly. The Bignose shark does have black tips on the inner corners of the pectoral fins. It has been observed that when caught there is a green shine along the gills.
The Bignose shark appears to be large-built, yet slender. It has long, straight pectoral fins, and there is a ridge on its back between the two dorsal fins. The first dorsal fin has a bluntly pointed apex with an origin above or posterior to the axils of the pectoral fins. The anal fin originates slightly behind the origin of the second dorsal fin.
Biology and Reproduction: The Bignose shark is viviparous. Research suggests that birth is dependent upon location. August to September in the Mediterranean and from September to October in off the coast of Madagascar. Bignose shark litters are between 3 and 15 pups, with the typical litter size being 7. The pups are born between 28 and 35 inches long.
One litter of a Bignose shark could possibly be fathered by two or more males. Gestation is 10 months long on average.
Behavioral Traits, Sensing and Intelligence: Not much is known.
Bignose Shark Future and Conservation: The Bignose shark is not used commercially in United States, where it is listed as Prohibited Species under the 2007 Fishery Management Plan for Atlantic tunas, swordfish and sharks.
The Bignose shark is a bycatch of gillnet, bottom trawl, and deep-set pelagic longline fisheries (particularly those targeting tuna) in many parts of its range. It is regularly taken in the Caribbean and Cuban waters and used to produce liver oil, shagreen, and fishmeal. In Southeast Asia, the meat is consumed and the fins shipped to East Asia for shark fin soup.
Bignose Shark Recorded Attacks on Humans: The Bignose shark poses very little threat to humans.