Author: (Poey, 1868)
Field Marks:
A large grey shark with a long pointed snout, large eyes, oblique-cusped upper antero- lateral teeth with smooth or weakly serrated cusps and strong cusplets, lower teeth with erect to semierect cusps but no cusplets, usually 15/15 rows of anterolateral teeth, an interdorsal ridge, moderate-sized pectoral fins, a small first dorsal with a moderately long rear tip and a low second dorsal with a long rear tip, and no conspicuous markings on fins.
Diagnostic Features:
A fairly slender species (up to about 2.8 m). Snout very long and moderately pointed; internarial width 1.7 to 1.9 times in preoral length; eyes circular and moderately large, their length 1.8 to 2.7% of total length; upper labial furrows short and inconspicuous; hyomandibular line of pores just behind mouth corners not conspicuously enlarged; gill slits short the third 2.5% of total length and less than a third of first dorsal base; usually 15/15 rows of anteroposterior teeth in each jaw half; upper teeth with narrow, smooth or irregularly serrated, oblique cusps, and crown feet with strong distal cusplets (young) or coarse proximal and distal serrrations or weak cusplets (adults); lower teeth with erect, smooth cusps and transverse roots. Interdorsal ridge present. First dorsal fin small and triangular, with a pointed or narrowly rounded apex and posterior margin curving posteroventrally from fin apex; origin of first dorsal fin over pectoral free rear tips; inner margin of first dorsal moderately long, half of dorsal base or slightly less; second dorsal fin small and low, its height 1.7 to 2.1% of total length, its inner margin long and about 1.9 to 2.2 times its height; origin of second dorsal over or slightly posterior to anal origin; pectoral fins moderate-sized, slightly falcate, with narrowly to fairly broadly rounded apices; length of anterior margins about 17 to 18% of total length in individuals of all sizes; 184 to 192 total vertebral centra, 101 to 104 precaudal centra. Fins without conspicuous markings, sometimes small black spots scattered on body. An inconspicuous white band on flank.
Geographical Distribution:
Western Atlantic: Delaware to Florida, Bahamas, Cuba, ? Guayana; southern Brazil, Argentina. Eastern Atlantic: Senegal to Ivory Coast, Ghana to Cameroon, Zaire, Angola. ? Eastern Pacific: Panama.
Habitat and Biology:
A common deepwater coastal and semioceanic carcharhinid, occurring on or along the outer continental and insular shelves of the tropical and warmtemperate Atlantic. Prefers waters 50 to 100 m deep, but with considerable numbers reaching the surface and extending down to 200 m, and some occurring down to at least 600 m. The night shark is apparently a schooling species, uncommonly caught singly but often in groups; and caught at night or dawn rather than the day which indicates that it makes vertical migrations. Shows a seasonal variation in numbers off Cuba apparently as a result of geographic migrations. Recorded temperatures where it was caught off West Africa at depth of 90 to 285 m, 11 to 16°C; salinity 36°/oo; oxygen 1.81 ml/l (Poll, 1950).
Viviparous, with a yolk-sac placenta; number of young 4 to 12 per litter.
The night shark feeds mainly on small active bony fishes, including flyingfish, scombrids, butterfishes, sea basses and squid. It is apparently a relatively quick, active shark, but is not known to be dangerous to people.
Size:
Maximum 280 cm, adult females recorded at 178 to 179 cm, size at birth about 60 cm.
A length-weight curve for sharks caught off Cuba is:
WT = 0.2998 x 10 6TL3 738(Guitart Manday, 1975).
Interest to Fisheries:
This species is primarily fished off Cuba but is also caught in the eastern Atlantic, with longlines but occasionally also pelagic trawls, and utilized for fishmeal and oil.
Type material:
Holotype: ?. Type Locality: Cuba.