November Elasmobranch of the Month: Atlantic Sharknose Shark
Author Linda Weiss
Atlantic sharpnose sharks are a small species, averaging 1 m (3.3 feet) in length when full grown and weighing an average of 7.25 kg (16 pounds). As their name suggests, their snouts are long and pointed. Their body shape is slender, coloration is brown to gray on the top and sides, becoming cream-colored to white on the underside. Small white spots are often present on their top and sides. The first dorsal fin is located behind the pectoral fins and is significantly larger than the second dorsal fin. There is no interdorsal ridge. Their caudal (tail) fin has two slender lobes, with the upper lobe being more than twice as long as the lower lobe. Pectoral fins are located immediately behind the gills. Juveniles’ dorsal and caudal fins are edged in black. The lower and upper jaws contain 24-25 rows of triangular shaped teeth with smooth edges.
Image Credit: Andy Murch Elasmodiver
Habitat and Distribution
This shark resides year-round in the Atlantic Ocean off the East Coast of Florida and South Carolina, as well as in the Gulf of Mexico. It is also located along Brazil’s coast in the western Atlantic. The Atlantic Sharpnose prefers subtropical waters and are commonly located in the surf zones of sandy beaches. They can also be found in bays, harbors, estuaries and the mouths of rivers. They have the ability to survive in lower salinity waters, though they are not known to enter freshwater. During summer months they are typically found at depths of 12 meters (42 feet) or less, moving to deeper depths in excess of 27 meters (90 feet) during winter months.
The Atlantic Sharpnose’s diet includes invertebrates such as crab, shrimp, mollusks and squid. They also prey on small and juvenile vertebrates such as flounder, jacks, toadfish, eels, wrasses and filefish.
This shark species mates during the late spring and in early summer. After mating, females migrate offshore, returning near shore after 10-11 months, to give birth. Litter sizes range between 4-7 pups, that are 28-38 centimeters (11-15 inches.) long. Reproduction occurs viviparously, where the young develop inside the female, receiving nourishment through a placental sac before being birthed alive.
The IUCN Red List of Threatened Species currently lists the Atlantic Sharpnose shark as Least Concern, with an unknown population trend.
This shark’s natural predators include any larger, carnivorous fish, including larger sharks. Both sport and commercial fisheries target the Atlantic Sharpnose for human consumption as well as to use it as bait to fish for larger shark species. Because their fins are small in size, they are not a primary target in the shark fin trade. They are also commonly caught as bycatch in the shrimp fishing industry.
Fisheries and Oceans Canada
Florida Fish and Wildlife Conservation Commission
Virginia Institute of Marine Science
The IUCN Red List of Threatened Species
Cortés, E. 2009. Rhizoprionodon terraenovae. The IUCN Red List of Threatened Species 2009: e.T39382A10225086. https://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T39382A10225086.en. Downloaded on 01 November 2020.