Blacktip reef sharks are regularly caught by inshore fisheries and are vulnerable to depletion because of their small litter sizes and long gestation periods. Traumatogenic. May become aggressive to spear fishers and are reported to bite people wading in shallow water. Generally marketed fresh (as fillet), may be dried, salted, smoked or frozen. Fins are valued for shark-fin soup; a market that is decimating shark populations worldwide. They are also sought for their liver as source of oil.
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.
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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.
Caribbean reef sharks are sometimes seen resting motionless on the sea floor or inside caves; it is the first active shark species in which such a behavior was reported. In 1975, Eugenie Clark investigated the famed "sleeping sharks" inside the caves at Isla Mujeres off the Yucatan Peninsula, and determined that the sharks were not actually asleep as their eyes would follow divers. Clark speculated that freshwater upwellings inside the caves might loosen parasites on the sharks and produce an enjoyable "narcotic" effect. If threatened, Caribbean reef sharks sometimes perform a threat display, in which they swim in a short, jerky fashion with frequent changes in direction and repeated, brief (1–1.2 second duration) drops of the pectoral fins. This display is less pronounced than the better-known display of the grey reef shark (C. amblyrhynchos).
One useful definition distinguishes reefs from mounds as follows: Both are considered to be varieties of organosedimentary buildups – sedimentary features, built by the interaction of organisms and their environment, that have synoptic relief and whose biotic composition differs from that found on and beneath the surrounding sea floor. Reefs are held up by a macroscopic skeletal framework. Coral reefs are an excellent example of this kind. Corals and calcareous algae grow on top of one another and form a three-dimensional framework that is modified in various ways by other organisms and inorganic processes. By contrast, mounds lack a macroscopic skeletal framework (see stromatolite). Mounds are built by microorganisms or by organisms that don't grow a skeletal framework. A microbial mound might be built exclusively or primarily by cyanobacteria. Excellent examples of biostromes formed by cyanobacteria occur in the Great Salt Lake in Utah, and in Shark Bay on the coast of Western Australia.