| Synonyms
| | | | Hypoprion longirostris Poey, 1876 | | | Hypoprion bigelowi Cadenat, 1956 |
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| FAO Names | | En - Night shark, Fr - Requin de nuit, Sp - Tiburón de noche. |
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3Alpha Code: CCS Taxonomic Code: 1080201023 |
| Scientific Name with Original Description | | | Hypoprion signatus Poey, 1868. Repert. fis.-nat. Cuba, 2: 452, pl. 4, fig. 7-8. Holotype: ? Type Locality: Cuba. |
| Diagnostic Features
| | fieldmarks: A large gray shark with a long pointed snout, large eyes, oblique-cusped upper anterolateral 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.
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Large, fairly slender sharks (up to about 2.8 m) with snout very long and moderately pointed, internarial width 1.7 to 1.9 in preoral length. Eyes circular and moderately large, length 1.8-2.7%TL. Upper labial furrows short and inconspicuous. Hyomandibular line of pores just behind mouth corners not conspicuously enlarged.
Gill slits short, 3rd 2.5% TL 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 serrations or weak cusplets (adults); lower teeth with erect, smooth cusps and transverse roots.
Interdorsal ridge present. Pectoral fins moderate-sized, slightly falcate, with narrowly to fairly broadly rounded apices; length of anterior margins about 17-18%TL in individuals of all sizes. First dorsal fin small and triangular, with pointed or narrowly rounded apex and posterior margin curving posteroventrally from fin apex; origin of first dorsal fin over the pectoral free rear tips; inner margin of first dorsal moderately long, half dorsal base or slightly less. Second dorsal fin small and low, 1.7 to 2.1%TL, inner margin long and about 1.9-2.2 times times height; origin of second dorsal over or slightly posterior to anal origin.
184-192 total vertebral centra, 101-104 precaudal centra.
Fins without conspicuous markings, sometimes small black spots scattered on body. An inconspicuous white band on flank.
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| Geographical Distribution | |  | | Distribution Map |
| | 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 |  Launch the Aquatic Species Distribution map viewer |
| Habitat and Biology | | A common deepwater coastal and semioceanic carcharhinid, occurring on or along the outer continental and insular shelves and off the upper slopes of the tropical and warm-temperate 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 depths of 90 to 285 m are 11 to 16°C; salinity 36 ppt; 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. |
| Size | | | Maximum about 280 cm; adult females recorded at 178-179 cm; size at birth about 60 cm. A length-weight curve for fishes caught off Cuba is: WT = 0.2998 x 10-6 TL3.738 (Guitart Manday, 1975). |
| Interest to Fisheries | |
Global Capture production for
Carcharhinus signatus
(FAO Fishery Statistic) |  | 
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This species is primarily fished off Cuba but is also caught in the eastern Atlantic, with longlines but occasionally also pelagic trawls. No catch reported for this species to FAO for 1999.
and utilized for fishmeal and oil.
Castro et al. (in press) using various sources of scientific and anecdotal information arrive to the conclusion that night sharks have been nearly depleted from the southeastern coast of the United States and perhaps also the NW coast of Cuba. This species constituted 60-75% of the total shark catch of the Cuban shark fishery in the late 1930s when the average annual catch was of about 12,000 sharks (Martinez 1947; cited by Castro et al. in press). Guitart-Manday (1975) reported a rapid decrease in the mean weight per unit of effort of night sharks from 53.34 kg in 1971 to 21.11 kg in 1973 off the NW coast of Cuba. According to Berkeley and Campos (1988) night sharks represented 26.1 % of all sharks caught in swordfish fisheries off the East Coast of Florida in the early 1980s. Castro et al. (in press) report anecdotal accounts from commercial fishermen indicating that it was common to catch 50-80 night sharks in every set from Florida to the Carolinas in the late 1970s. These authors also report that sport fishermen landed large night sharks every day at the Miami docks in the 1970s. According to Castro et al. (in press) night sharks are now very rare in US waters. On the other hand, the occurrence of this species in the region is still evident in logbooks from the pelagic longlining fleet which show that the CPUE has varied with no trend for the period 1992-97 (Cramer 1998). In contrast to the above information and despite heavy shark fishing, night sharks continue to be commonly caught in the western Gulf of México by small-scale Mexican shark fishermen (Rodriguezet al. 1996, Bonfil 1997).
Conservation Status : The night shark has not been assessed for the IUCN Red List. The poor knowledge of the life history of night sharks prevents the estimation of its intrinsic rebound potential. However, its relatively limited range of distribution (it is known only from the NW Atlantic and the central equatorial Atlantic) and the apparent strong decline in its abundance due to unrestricted fishing in US and perhaps Cuban waters call for extreme caution in the exploitation of this species and urgent conservation action in US waters.
Additional information from IUCN database
Additional information from CITESdatabase | | | Related Fishing Techniques |
| Remarks | | Threat to humans: The night shark is not known to be dangerous to people.
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Bibliography Bigelow & Schroeder, (1948) Cadenat, (1956) Cadenat & Blache, (1981) Guitart, (1975) Poll, (1950) Raschi, Musick & Compagno, (1982) |
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