Galapagos Shark

Galapagos SharkThe galapagos shark (Carcharhinus galapagensis) is a large shark with a moderately long broadly rounded snout. Origin of the first dorsal fin over the mid lengths of inner margins of the pectoral fins. A low interdorsal ridge is present. Brownish-grey upper body, white ventral surface. The tips of most fins are dusky but not black. An inconspicuous white band on the flanks can be seen.

Contrary to the name, they can be found circumtropical but generally associated with oceanic islands. Western North Atlantic: Bermuda, Virgin Islands and some other Caribbean Islands. Central and Eastern Atlantic: Madeira, possibly of Portugal, Cape Verde, Ascension, St. Helena and Sao Thome Islands. Southwestern Indian Ocean: Madagascar. Western central Pacific: Middleton, Marshall Islands, Tuamoto Archipelago, Hawaiian Islands. E astern Pacific: Galapagos Islands, Cocos Islands, Malpelo Islands, also coasts of southern Baja California, Guatemala and Colombia.

This shark is quite abundant in waters around oceanic islands, found close inshore as well as occasionally reported offshore in waters over continental and insular shelves to depths of 591 feet (180 m). It has a preference for clear tropical waters with strong currents over coral or rocky bottom habitats. Although it is considered a coastal species, the Galapagos shark has been reported to cross open waters between islands. Juveniles are limited to waters shallower than 82 feet (25 m), which act as nursery grounds and help avoid cannibalism by their own parents. This shark often swims just above the bottom substrate, forming loose aggregations.

This shark feeds primarily on bottom-dwelling fishes as well as on squid and octopus. These fish include eels, flatheads, groupers, flatfish, and triggerfish. As Galapagos sharks reach large sizes, they also feed on other elasmobranchs. In the Galapagos Islands off the coast of Ecuador, it has been observed preying on sea lions and marine iguanas. The Galapagos shark displays threat gestures to warn competitors in the search for food.

Galapagos sharks are "viviparous", or livebearing, with embryos nourished by a yolksac-placenta during gestation. Mating and birth occurs early in the year within Hawaiian waters. Female individuals often have mating scars from males biting the gills, fins, and body. After gestation during which the embryos develop inside the mother, live birth results in a litter size of 4-16 pups. Each pup measures 24-31 inches (60-80 cm) in length. The pups stay in shallow water nursery areas to avoid predation and cannibalism from members of their own species, eventually moving out to deeper waters as they mature.


 
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