Finetooth SharkCarcharhinus isodon
The finetooth shark has a small, slender body and a long, pointed nose and large eyes. It gets its name from its rows of small, fine, clear teeth in its wide mouth. This social shark forms schools to hunt small bony fish like menhanden and mullet, sometimes energetically chasing them into the beach surf.
Order - Carcharhiniformes
Family - Carcharhinidae
Genus - Carcharhinus
Species - isodon
English language common names include finetooth shark, eventooth shark, night shark, shark, and smoothtooth shark. Other common names from around the world include fijntandhaai (Dutch), galana dientefino (Spanish), requin à petites dents (French), tiburón de noche (Spanish), and tiburón dentiliso (Spanish).
Importance to HumansIn the western Atlantic, this shark may be incidental by-catch but is considered to have little overall economic importance to the commercial shark fishery. It is primarily caught with floating longlines in inshore waters. This shark is sometimes targeted by gillnet fisheries close to shore and may be of local economic importance. In the northern Gulf of Mexico, it is taken occasionally by rod and reel. This shark is marketed either fresh or dried-salted for human consumption.
Danger to Humans
Although this species in not implicated in any unprovoked shark attacks, caution should be used while in the water with the finetooth shark or handling a captured shark on the deck of a vessel.
The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species.
Geographical DistributionThe finetooth shark is distributed in the western Atlantic Ocean from North Carolina (U.S.) south to Cuba and southern Brazil, including the Gulf of Mexico. Although there have been reports of this shark in the eastern Atlantic Ocean, in particular in Senegal and Guinea-Bissau, these sightings have not been confirmed and may be a result of confusion with the spinner shark (Carcharhinus brevipinna).
Residing in waters close to shore to depths of 32.8 feet (10 m), this coastal species often forms large schools. Adults and juveniles are common in shallow coastal waters off South Carolina during the warm summer months and migrate south when surface water temperatures drop below 68°F (20°C). This population of finetooth sharks spend the winter months in the waters off the coast of Florida.
1. Snout pointed, shorter than the width of the mouth
2. Fins unmarked, the undersides of the pectoral fins are pure white
3. First dorsal fin originates behind the insertion point of pectoral fins along inner margin
The finetooth shark is small in size with a long pointed snout and fairly large eyes. The mouth is broadly rounded in the front with well-defined labial furrows around the corner of the mouth. The gill slits are very long, about half the length of the base of the first dorsal fin. The origin of the first dorsal fin is over or just slightly posterior to the insertions of the pectoral fins. The first dorsal fin is small with a short rear tip. The trailing edge of the first dorsal is falcate with a rounded apex. The second dorsal fin is moderately large with a short rear tip. The pectoral fins are small. Pelvic fins have narrowly rounded tips. The upper edge of the caudal fin is just about straight with a narrowly rounded tip. There is no interdorsal ridge on the finetooth shark.
Species appearing similar to the finetooth shark include the lemon shark (Negaprion brevirostris), blacktip shark (Carcharhinus limbatus), and spinner shark (Carcharhinus brevipinna). The lemon shark can be distinguished by its second dorsal fin that is almost as large as its first dorsal. The blacktip shark and spinner shark have black-tipped fins while the finetooth shark lacks any distinguishing markings on the fins.
This shark is dark bluish-grey or bronze above, paling to grayish then to a white underside. There is an inconspicuous white band along the flank. There are no distinguishing marks on the fins.
This shark is named for its very small, clear, fine teeth. The upper teeth are narrow and weakly serrated or smooth with erect to slightly oblique cusps. The lower teeth are erect with smooth cusps and transverse roots.
Dermal denticles of the finetooth shark are small and overlapping. Each denticle is a bit broader than long with blades containing three ridges, each with three short teeth with the median tooth longest.
Size, Age, and Growth
Maximum reported size of the finetooth shark is 6.2 feet (1.9 m) TL. Average lengths for male individuals is 5.2 feet (1.6 m) while females average about 5.4 feet (1.7 m). Males reach maturity at about 3.9 feet (1.2 m) in length and females mature at about 4.6 feet (1.4 m).
The finetooth shark feeds on small bony fishes, including mullet, Spanish mackerel, spot, and Atlantic menhaden. This shark also preys on marine invertebrates including cephalopods and crustaceans.
Finetooth sharks may fall prey to larger sharks including the dusky shark.
The finetooth shark was originally named Carcharias isodon by Valenciennes in 1839. However, the name combination was changed to Carcharhinus isodon later that same year (Valenciennes, 1839). The genus name Carcharhinus is derived from the Greek "karcharos" = sharpen and "rhinos" = nose. The species name isodon means "equal tooth" for the same number of teeth located in the upper and lower jaws. A synonym referring to this species in previous scientific literature is Aprionodon punctatus Gill 1861.
Prepared by: Cathleen Bester