The Digital Fish Library

Distribution:
Tropical to warm temperate waters of the Atlantic, Indian and Pacific oceans, some species enter freshwater.

Habitat:
Continental and insular shelves and slopes, often over coral reefs; also oceanic.

Remarks:
Sharks in the Carcharhinid family span a range of sizes, the smallest of which are less than 100 cm TL and the largest of which can reach 7.4 m. They are the most abundant shark species in tropical waters in terms of biomass and biodiversity, and consequently are of great importance to tropical fisheries.

All species in this family give birth to live young except for the largest species, the Tiger Shark, which is ovoviviparous (eggs are retained and hatched within the mother).

Diagnostic characteristics of carcharinid sharks include undulated dorsal fin margins, a precaudal pit, and five gill openings (the fifth located behind the origin of the pectoral fin). They lack barbels and nasoral grooves and often lack spiracles as well. Their eyes may be circular or oval, with internal eyelids that are capable of blinking. The teeth are usually bladelike with a single cusp. The intestine has a scroll valve, but lacks the spiral valve.

Requiem sharks are strong swimmers and may occur singly or in small or even larger groups. When approached by divers, several species give aggressive or defensive warning displays. Sharks in this family are responsible for half of all reported attacks on humans.

This family contains 12 genera and at least 50 species. It is unclear based on morphological and molecular data whether the hammerhead sharks should be included in this family.

References:
Allen & Robertson 1994; Compagno 1984 in: FAO; Nelson 2006