Blacktip Shark
Appearance: Shark with a long and pointed snout. Small eyes. Origin of the first dorsal fin usually over or slightly behind the insertion of the pectoral fins. Coloration: Grey, grey-brown or bluish grey upper body, white ventral surface. Black tips usually present on pectoral fins, second dorsal fin, and ventral caudal lobe, and sometimes on pelvic fins. The tip of the anal fin is usually plain (no black tip). A conspicuous white band on the flanks.
Distribution: Widespread in all tropical and subtropical waters over continental shelves. Western Atlantic: Massachusetts to southern Brazil. Bahamas, the Caribbean and Gulf of Mexico. This is 黑料天堂"s most common large coastal shark.
Biology: The blacktip shark is a common tropical and warm-temperate species of inshore and offshore pelagic waters. Commonly occurs in close inshore waters, off river mouths and estuaries, muddy bays, mangrove swamps, island lagoons and along drop-offs on coral reefs as well as far offshore. Rarely found in water deeper than 90'. A very active, fast-swimming species that often occurs in large schools at the surface. It leaps out of the water, and like the related spinner shark (Carcharhinus brevipinna) rotates around its axis before dropping back into the sea. This behavior is thought to be used by the shark while feeding on small schooling fishes. The shark launches itself vertically through the schools, spinning and snapping in all directions, and then breach the surface after the feeding run. Its social behavior makes it subject to feeding frenzies when a number of sharks compete for a highly concentrated food source.
Feeding: Primarily a fish-eater (sardines, herrings, anchovies) as well as small sharks such as sharpnose sharks (Rhizoprionodon), and a variety of young of larger shark species. Size: Average size about 5 ft.and 50 lbs, maximum 8 ft.
Reproduction: Viviparous, with yolksac-placenta. 1 to 10 pups per litter, commonly 4 to 7. Size at birth about 1.5 to 2 ft. Gestation period is 10 to 12 months. Males mature between 4.5 and 6 ft, females mature between 4 and 6 ft. Estimated life span about 12 years. Similar species: Several similar looking species look. Although the coloration (fin markings, white band) is fairly unique, additional diagnostic features might be necessary to distinguish among the species.
Population Status: Unknown if population sizes are decreasing, but it is a common fisheries species and decreases might be possible in the near future.
Danger to humans: Very few attacks on people have been attributed to this species, and it is likely that without a food stimulus or other special circumstances that this species is of little hazard to people.
