Sandbar shark (C. plumbeus): The sandbar shark has a snout that is shorter than the width of its mouth and a large first dorsal fin originating over the axis of the pectoral fin (the Caribbean reef shark’s first dorsal fin is further from the head than the sandbar shark). Unlike the Caribbean reef shark, the sandbar shark has widely spaced non-overlapping dermal denticles that lack defined teeth on their free edges.
This species is taken by commercial and artisanal longline and gillnet fisheries throughout its range. It is valued for meat, leather, liver oil and fishmeal. The Caribbean reef shark is the most common shark landed in Colombia (accounting for 39% of the longline catch by occurrence), where it is utilized for its fins, oil and jaws (sold for ornamental purposes). In Belize, this species is mainly caught as bycatch on hook-and-line intended for groupers and snappers; the fins are sold to the lucrative Asian market and the meat sold in Belize, Mexico, and Guatemala to make "panades", a tortilla-like confection. A dedicated shark fishery operated in Belize from the mid-1900s to the early 1990s, until catches of all species saw dramatic declines. The flesh of this species may contain high levels of methylmercury and other heavy metals.
Like many sharks, the Caribbean reef shark mainly eats bony fishes. The shark uses six keen senses to locate its prey: olfactory, visual, tactile (including water vibration sensitivity through a lateralis canal system), auditory, gustatory, and electric reception. The Caribbean reef shark is especially adapted to detecting low frequency sounds (indicative of a struggling fish nearby).
Blacktip reef sharks are viviparous with a yolk-sac placenta, with a gestation period about 10 months and litter size of 2-4 pups. Size at birth ranges from 33-52 cm. Males mature at about eight years of age and 95-105 cm in length; females mature at about 9 years old and a length of 93-110 cm. Courtship features the one or more males following closely behind a female. Reproductive behavior includes distinct pairing with embrace where the male grasps the female’s pectoral fin between his teeth and mates belly to belly. There is one breeding season in the central and western Pacific, but two seasons in the Indian Ocean. Females rest for 8-14 month between pregnancies to rebuild their energy stores. Blacktip reef sharks are preyed upon by other sharks and large groupers. The is a socially complex species that performs a variety of group behaviors.
Adults begin to reproduce once they attain a size of 2 to 3 meters (female) or 1.5 to 1.7 meters (male). They reproduce once per year but childbirth is biennial since the females get pregnant every other year. The reproduction method is Viviparous which means the pups develop inside of the mother. There is evidence that the reproduction method is aggressive and violent since many female Caribbean Reef Sharks have been found with deep wounds on their sides during mating season. These wounds are caused by bites and heal in time leaving large and highly visible scars.
Although there are no active reef shark fisheries in the US Pacific, the reef sharks' disappearance could be caused by recreational fishing or illegal shark finning, which, combined, kill 26 million to 73 million sharks each year. Another possible explanation is that the reef sharks are starving. Their food sources, including coral reef fishes, are decreasing in number because of habitat destruction and human exploitation, and could be taking the sharks with them.
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