Atlantic Sharpnose Shark

View all available Atlantic Sharpnose Shark Pictures in the Shark Picture Database

Common Names: Atlantic sharpnose shark, sand shark, mud shark.

Latin Name: Rhizoprionodon terraenovae

Family: Carcharhinidae

Identification: Long pointed snout. Slender body is grey/brown above usually with scattered white spots. First dorsal starts just behind trailing edge of pectoral fin. Second dorsal very low with long free rear tip. Pectoral fins have conspicuous thin white posterior margin. Trailing edge of caudal fin and second dorsal sometimes slightly dusky.

Size: At birth 29-37cm. Males mature at 65-80cm. Females mature at 85-90.

Habitat: Intertidal to 280m. Mostly over sandy or muddy bottoms. females migrate inshore during the summer months to give birth. Males in the northern Gulf of Mexico enter extremely shallow turbid water over the summer. It is unclear exactly why they choose this environment because the salinity and available dissolved oxygen in these areas is very low leading to a sparse food supply. Dr Eric Hoffmeyer has demonstrated that during this time the mail Atlantic sharpnose sharks live off the oil reserves stored in their livers. By the end of the summer the liver shrinks considerably.

Distribution: Western Atlantic Ocean from New England to the Yucatan in Mexico and possibly further south. As it is difficult to positively identify the Atlantic sharpnose shark from the Caribbean sharpnose shark (R.porosus) which has a more southerly range, the southern boundary of R.terraenovae is debatable.

Abundance: An abundant species in US waters. No directed fishery. IUCN red list: least concern. Atlantic sharpnose sharks may actually be profiting from the plight of other larger shark species that are no longer there to prey on them.

Behavior: Little known

Reproduction: Viviparous with yolk sac placenta. Litter size 1 to 7. Size of litter corresponds to relative size of the mother. Gestation listed as 10-11 months.

Observations: I noticed that all of the released Atlantic sharpnose sharks that I saw underwater swam away with their mouths agape. As this is not particularly efficient in a hydrodynamic sense this may be a reaction to the stress of capture and a way to temporarily increase oxygen intake - the equivalent of breathing hard.

Photographs: Mississippi Barrier Islands. These rare images of free swimming Atlantic sharpnose sharks could not have been taken without the help of Dr Eric Hoffmeyer and the staff at the Gulf Coast Research Laboratory in Ocean Springs, MS. Many thanks to Eric and everyone that helped make this happen!

Similar species: The Caribbean sharpnose shark R.porosus is virtually identical to R.terraenovae. Positive identification can only be made through vertebral counts and DNA analysis. These two sharks may ultimately prove to be the same species.

Reaction to divers: Due to their small size, timidity and preference for turbid inshore water, it is very unusual for scuba divers to encounter Atlantic sharpnose sharks in the wild.

Diving logistics: See reaction to divers above. Elasmodiver would be very interested in hearing about any natural encounters.

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ATLANTIC SHARPNOSE SHARK