Caribbean reef shark
Encyclopedia
The Caribbean reef shark (Carcharhinus perezi, often misspelled perezii) is a species
of requiem shark
, family
Carcharhinidae. It is found in the tropical waters of the western Atlantic Ocean
from Florida
to Brazil
, and is the most commonly encountered reef shark in the Caribbean Sea
. With a robust, streamlined body typical of the requiem sharks, this species is difficult to tell apart from other large members of its family such as the dusky shark
(C. obscurus) and the silky shark
(C. falciformis). Distinguishing characteristics include dusky-colored fins without prominent markings, a short free rear tip on the second dorsal fin
, and tooth shape and number.
Measuring up to 3 m (10 ft) long, the Caribbean reef shark is one of the largest apex predator
s in the reef ecosystem
, feeding on a variety of fishes and cephalopod
s. They have been documented resting motionless on the sea bottom or inside caves, unusual behavior for an active-swimming shark. If threatened, it may perform a threat display
in which it frequently changes direction and dips its pectoral fins. Like other requiem sharks, it is viviparous with females giving birth to 4–6 young every other year. Caribbean reef sharks are of some importance to fisheries as a source of meat, leather
, liver oil
, and fishmeal, but recently they have become more valuable as an ecotourist
attraction. In the Bahamas and elsewhere, bait is used to attract them to groups of divers in controversial "shark feedings". This species is responsible for a small number of attacks
on humans.
in 1876, in the scientific journal
Anales de la Sociedad Española de Historia Natural. The type specimens were six individuals caught off the coast of Cuba
. The genus
Platypodon was synonymized
with Carcharhinus by later authors.
Based on morphological
similarities, Jack Garrick in 1982 grouped this species with the bignose shark
(C. altimus) and the sandbar shark
(C. plumbeus), while Leonard Compagno
in 1988 placed it as the sister species of the grey reef shark (C. amblyrhynchos). A phylogenetic analysis based on allozyme
data, published by Gavin Naylor in 1992, indicated that the Caribbean reef shark is the sister taxon
to a clade
formed by the Galapagos shark
(C. galapagensis), dusky shark
(C. obscurus), oceanic whitetip shark
(C. longimanus), and the blue shark
(Prionace glauca). However, more work is required to fully resolve the interrelationships within Carcharhinus.
, from North Carolina
in the north to Brazil
in the south, including Bermuda
, the northern Gulf of Mexico
, and the Caribbean Sea
. However, it is extremely rare north of the Florida Keys
. It prefers shallow waters on or around coral reef
s, and is commonly found near the drop-offs at the reefs' outer edges. This shark is most common in water shallower than 30 m (98.4 ft), but has been known to dive to 378 m (1240 feet).
A heavy-bodied shark with a "typical" streamlined shape, the Caribbean reef shark is difficult to distinguish from other large requiem shark species. It usually measures 2–2.5 m (6.5–8 ft) long; the maximum recorded length is 3 m (10 ft) and the maximum reported weight is 70 kg (154 lbs). The coloration is dark gray or gray-brown above and white or white-yellow below, with an inconspicuous white band on the flanks. The fins are not prominently marked, and the undersides of the paired fins, the anal fin, and the lower lobe of the caudal fin are dusky.
The snout is rather short, broad, and rounded, without prominent flaps of skin beside the nostrils. The eyes are large and circular, with nictitating membrane
s (protective third eyelids). There are 11–13 tooth rows in either half of both jaws. The teeth have broad bases, serrated edges, and narrow cusps; the front 2–4 teeth on each side are erect and the others increasingly oblique. The five pairs of gill slit
s are moderately long, with the third gill slit over the origin of the pectoral fins. The first dorsal fin
is high and falcate (sickle-shaped). There is a low interdorsal ridge running behind it to the second dorsal fin, which is relatively large with a short free rear tip. The origin of the first dorsal fin lies over or slightly forward of the free rear tips of the pectoral fins, and that of the second dorsal fin lies over or slightly forward of the anal fin. The pectoral fins are long and narrow, tapering to a point. The dermal denticles are closely spaced and overlapping, each with five (sometimes seven in large individuals) horizontal low ridges leading to marginal teeth.
Despite its abundance in certain areas, the Caribbean reef shark is one of the least-studied large requiem sharks. They are believed to play a major role in shaping Caribbean reef communities. These sharks are more active at night, with no evidence of seasonal changes in activity or migration
. Juveniles tend to remain in a localized area throughout the year, while adults range over a wider area.
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).
Juvenile Caribbean reef sharks are preyed upon by larger sharks such as the tiger shark
(Galeocerdo cuvier) and the bull shark
(C. leucas). Few parasites are known for this species; one is a dark variegated leech
often seen trailing from its first dorsal fin. Off northern Brazil, juveniles seek out cleaning stations occupied by yellownose gobies (Elacatinus randalli), which clean the sharks of parasites while they lie still on the bottom. Horse-eye jack
s (Caranx latus) and bar jack
s (Carangoides ruber) routinely school
around Caribbean reef sharks.
The Caribbean reef shark feeds on a wide variety of reef-dwelling bony fishes and cephalopods, as well as some elasmobranchs such as eagle ray
s (Aetobatus narinari) and yellow stingray
s (Urobatis jamaicensis). It is attracted to low-frequency sound
s, which are indicative of struggling fish. In one observation of a 2 m (6.6 ft) long male Caribbean reef shark hunting a yellowtail snapper
(Lutjanus crysurus), the shark languidly circled and made several seemingly "half-hearted" turns towards its prey, before suddenly accelerating and swinging its head sideways to capture the snapper at the corner of its jaws. Young sharks feed on small fishes, shrimps, and crabs. Caribbean reef sharks are capable of everting their stomach
s, which likely serves to cleanse indigestible particles, parasites, and mucus from the stomach lining.
s exhaust their supply of yolk, the yolk sac
develops into a placenta
l connection through which they receive nourishment from their mother. Mating is apparently an aggressive affair, as females are often found with biting scars and wounds on their sides. At the Fernando de Noronha Archipelago and Atol das Rocas off Brazil, parturition takes place at the end of the dry season
from February to April, while at other locations in the Southern Hemisphere, females give birth during the Amazon
summer in November and December. The average litter size is four to six, with a gestation period
of one year. Females become pregnant every other year. The newborns measure no more than 74 cm (29 in) long; males mature sexually at 1.5–1.7 m (60–66 in) long and females at 2–3 m (79–116 in).
lists 27 attacks attributable to this species, 4 of them unprovoked, and none fatal.
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 grouper
s and snapper
s; 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.
; its population has declined off Belize and Cuba from overfishing
and exploitation continues in other regions. They are also threatened by the degradation and destruction of their coral reef habitat. Commercial fishing for this species is prohibited in United States
waters. They are protected in the Bahamas due to their significance to ecotourism, as well as in a number of Marine Protected Area
s (MPAs) off Brazil and elsewhere. However, enforcement against illegal fishing is lacking in some of these reserves, and many areas in which this species is abundant are not yet protected.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of requiem shark
Requiem shark
Requiem sharks are a family, Carcharhinidae, of sharks in the order Carcharhiniformes, containing migratory, live-bearing sharks of warm seas such as the tiger shark, the blue shark, the bull shark, and the milk shark.The name may be related to the French word for shark, "requin", itself of...
, family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Carcharhinidae. It is found in the tropical waters of the western Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
from Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
to Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, and is the most commonly encountered reef shark in the Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
. With a robust, streamlined body typical of the requiem sharks, this species is difficult to tell apart from other large members of its family such as the dusky shark
Dusky shark
The dusky shark is a species of requiem shark, family Carcharhinidae, occurring in tropical and warm-temperate continental seas worldwide. A generalist apex predator, the dusky shark can be found from the coast to the outer continental shelf and adjacent pelagic waters, and has been recorded from...
(C. obscurus) and the silky shark
Silky shark
The silky shark is a species of requiem shark, family Carcharhinidae, named for the smooth texture of its skin. It is one of the most abundant sharks in the pelagic zone, and can be found around the world in tropical waters. Highly mobile and migratory, this shark is most often found over the edge...
(C. falciformis). Distinguishing characteristics include dusky-colored fins without prominent markings, a short free rear tip on the second dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
, and tooth shape and number.
Measuring up to 3 m (10 ft) long, the Caribbean reef shark is one of the largest apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
s in the reef ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
, feeding on a variety of fishes and cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s. They have been documented resting motionless on the sea bottom or inside caves, unusual behavior for an active-swimming shark. If threatened, it may perform a threat display
Shark threat display
Shark threat display, a type of agonistic display, is a behaviour observed in some sharks when they feel threatened or protective. It consists of a contorting of the body into a series of "ritualized" postures coupled with an exaggerated swimming style...
in which it frequently changes direction and dips its pectoral fins. Like other requiem sharks, it is viviparous with females giving birth to 4–6 young every other year. Caribbean reef sharks are of some importance to fisheries as a source of meat, leather
Leather
Leather is a durable and flexible material created via the tanning of putrescible animal rawhide and skin, primarily cattlehide. It can be produced through different manufacturing processes, ranging from cottage industry to heavy industry.-Forms:...
, liver oil
Shark liver oil
Shark liver oil is obtained from sharks that are caught for food purposes and are living in cold, deep oceans. The liver oil from sharks has been used by fishermen for centuries as a folk remedy for general health...
, and fishmeal, but recently they have become more valuable as an ecotourist
Ecotourism
Ecotourism is a form of tourism visiting fragile, pristine, and usually protected areas, intended as a low impact and often small scale alternative to standard commercial tourism...
attraction. In the Bahamas and elsewhere, bait is used to attract them to groups of divers in controversial "shark feedings". This species is responsible for a small number of attacks
Shark attack
A shark attack is an attack on a human by a shark. Every year around 60 shark attacks are reported worldwide, although death is quite unusual. Despite the relative rarity of shark attacks, the fear of sharks is a common phenomenon, having been fueled by the occasional instances of serial attacks,...
on humans.
Taxonomy and phylogeny
The Caribbean reef shark was originally described as Platypodon perezi by Felipe PoeyFelipe Poey
-Biography:Poey was born in Havana, the son of French and Spanish parents. He spent several years of his life in Pau then studied law in Madrid. He became a lawyer in Spain but was forced to leave due to his liberal ideas, returning to Cuba in 1823. He began to concentrate on the study of the...
in 1876, in the scientific journal
Scientific journal
In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. There are thousands of scientific journals in publication, and many more have been published at various points in the past...
Anales de la Sociedad Española de Historia Natural. The type specimens were six individuals caught off the coast of Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
. The genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Platypodon was synonymized
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
with Carcharhinus by later authors.
Based on morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
similarities, Jack Garrick in 1982 grouped this species with the bignose shark
Bignose shark
The bignose shark is a species of requiem shark, family Carcharhinidae. Distributed worldwide in tropical and subtropical waters, this migratory shark frequents deep waters around the edges of the continental shelf. It is typically found at depths of , though at night it may move towards the...
(C. altimus) and the sandbar shark
Sandbar shark
The sandbar shark, Carcharhinus plumbeus, is a species of requiem shark, family Carcharhinidae, native to the Atlantic Ocean and the Indo-Pacific. It is distinguishable by its very high first dorsal fin and inter-dorsal ridge....
(C. plumbeus), while Leonard Compagno
Leonard Compagno
Leonard Joseph Victor Compagno is an international authority on shark taxonomy and the author of many scientific papers and books on the subject, best known of which is his 1984 catalogue of shark species produced for the Food and Agriculture Organization of the United Nations.-Career:*Ph.D,...
in 1988 placed it as the sister species of the grey reef shark (C. amblyrhynchos). A phylogenetic analysis based on allozyme
Allozyme
Variant forms of an enzyme that are coded by different alleles at the same locus are called allozymes. These are opposed to isozymes, which are enzymes that perform the same function, but which are coded by genes located at different loci....
data, published by Gavin Naylor in 1992, indicated that the Caribbean reef shark is the sister taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
to a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
formed by the Galapagos shark
Galapagos shark
The Galapagos shark is a species of requiem shark, family Carcharhinidae, found worldwide. This species favors clear reef environments around oceanic islands, where it is often the most abundant shark species...
(C. galapagensis), dusky shark
Dusky shark
The dusky shark is a species of requiem shark, family Carcharhinidae, occurring in tropical and warm-temperate continental seas worldwide. A generalist apex predator, the dusky shark can be found from the coast to the outer continental shelf and adjacent pelagic waters, and has been recorded from...
(C. obscurus), oceanic whitetip shark
Oceanic whitetip shark
The oceanic whitetip shark, Carcharhinus longimanus, is a large pelagic shark inhabiting tropical and warm temperate seas. Its stocky body is most notable for its long, white-tipped, rounded fins....
(C. longimanus), and the blue shark
Blue shark
The blue shark is a species of requiem shark, family Carcharhinidae, that inhabits deep waters in the world's temperate and tropical oceans. Preferring cooler waters, blue sharks migrate long distances, for example from New England to South America. Although generally lethargic, they can move very...
(Prionace glauca). However, more work is required to fully resolve the interrelationships within Carcharhinus.
Distribution and habitat
The Caribbean reef shark occurs throughout the tropical western Atlantic OceanAtlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
, from North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
in the north to Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
in the south, including Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
, the northern Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
, and the Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
. However, it is extremely rare north of the Florida Keys
Florida Keys
The Florida Keys are a coral archipelago in southeast United States. They begin at the southeastern tip of the Florida peninsula, about south of Miami, and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry...
. It prefers shallow waters on or around coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
s, and is commonly found near the drop-offs at the reefs' outer edges. This shark is most common in water shallower than 30 m (98.4 ft), but has been known to dive to 378 m (1240 feet).
Description
The snout is rather short, broad, and rounded, without prominent flaps of skin beside the nostrils. The eyes are large and circular, with nictitating membrane
Nictitating membrane
The nictitating membrane is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten it while maintaining visibility. Some reptiles, birds, and sharks have a full nictitating membrane; in many mammals, there is a small...
s (protective third eyelids). There are 11–13 tooth rows in either half of both jaws. The teeth have broad bases, serrated edges, and narrow cusps; the front 2–4 teeth on each side are erect and the others increasingly oblique. The five pairs of gill slit
Gill slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of Cartilaginous fish such as sharks, rays, sawfish, and guitarfish. Most of these have five pairs, but a few species have 6 or 7 pairs...
s are moderately long, with the third gill slit over the origin of the pectoral fins. The first dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
is high and falcate (sickle-shaped). There is a low interdorsal ridge running behind it to the second dorsal fin, which is relatively large with a short free rear tip. The origin of the first dorsal fin lies over or slightly forward of the free rear tips of the pectoral fins, and that of the second dorsal fin lies over or slightly forward of the anal fin. The pectoral fins are long and narrow, tapering to a point. The dermal denticles are closely spaced and overlapping, each with five (sometimes seven in large individuals) horizontal low ridges leading to marginal teeth.
Biology and ecology
Fish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...
. Juveniles tend to remain in a localized area throughout the year, while adults range over a wider area.
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
Eugenie Clark
Eugenie Clark , popularly known as The Shark Lady, is an American ichthyologist known for her research on poisonous fish of the tropical seas and on the behaviour of sharks.-Academic life:...
investigated the famed "sleeping sharks" inside the caves at Isla Mujeres
Isla Mujeres
Isla Mujeres is one of the ten municipalities of the Mexican state of Quintana Roo. The municipality, located in the northeastern corner of the state is mostly on the mainland and has a municipal seat of the same name; Isla Mujeres...
off the Yucatan Peninsula
Yucatán Peninsula
The Yucatán Peninsula, in southeastern Mexico, separates the Caribbean Sea from the Gulf of Mexico, with the northern coastline on the Yucatán Channel...
, 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
Shark threat display
Shark threat display, a type of agonistic display, is a behaviour observed in some sharks when they feel threatened or protective. It consists of a contorting of the body into a series of "ritualized" postures coupled with an exaggerated swimming style...
, 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).
Juvenile Caribbean reef sharks are preyed upon by larger sharks such as the tiger shark
Tiger shark
The tiger sharks, Galeocerdo cuvier, is a species of requiem shark and the only member of the genus Galeocerdo. Commonly known as sea tigers, tiger sharks are relatively large macropredators, capable of attaining a length of over . It is found in many tropical and temperate waters, and is...
(Galeocerdo cuvier) and the bull shark
Bull shark
The bull shark, Carcharhinus leucas, also known as Zambezi shark or unofficially known as Zambi in Africa and Nicaragua shark in Nicaragua, is a shark common worldwide in warm, shallow waters along coasts and in rivers...
(C. leucas). Few parasites are known for this species; one is a dark variegated leech
Leech
Leeches are segmented worms that belong to the phylum Annelida and comprise the subclass Hirudinea. Like other oligochaetes such as earthworms, leeches share a clitellum and are hermaphrodites. Nevertheless, they differ from other oligochaetes in significant ways...
often seen trailing from its first dorsal fin. Off northern Brazil, juveniles seek out cleaning stations occupied by yellownose gobies (Elacatinus randalli), which clean the sharks of parasites while they lie still on the bottom. Horse-eye jack
Horse-eye jack
The Horse-eye Jack, Caranx latus, is a gamefish and minor commercial fish in the family Carangidae. It is also known as the Big-eye jack, and is similar in appearance to the Crevalle jack, although the head of a Horse-eye jack is not as blunt...
s (Caranx latus) and bar jack
Bar jack
The bar jack, Carangoides ruber is a common species of inshore marine fish classified in the jack family, Carangidae...
s (Carangoides ruber) routinely school
Shoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...
around Caribbean reef sharks.
Feeding
Eagle ray
The eagle rays are a group of cartilaginous fishes in the family Myliobatidae, consisting mostly of large species living in the open ocean rather than on the sea bottom....
s (Aetobatus narinari) and yellow stingray
Yellow stingray
The yellow stingray is a species of stingray in the family Urotrygonidae, found in the tropical western Atlantic Ocean from North Carolina to Trinidad. This bottom-dwelling species inhabits sandy, muddy, or seagrass bottoms in shallow inshore waters, commonly near coral reefs...
s (Urobatis jamaicensis). It is attracted to low-frequency sound
Sound
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...
s, which are indicative of struggling fish. In one observation of a 2 m (6.6 ft) long male Caribbean reef shark hunting a yellowtail snapper
Yellowtail snapper
The yellowtail snapper, Ocyurus chrysurus, is an abundant species of snapper found along the North American coast of the Atlantic Ocean. Although they have been found as far north as Massachusetts, their normal range is along Florida down through the West Indies and Brazil.In certain reefs, most...
(Lutjanus crysurus), the shark languidly circled and made several seemingly "half-hearted" turns towards its prey, before suddenly accelerating and swinging its head sideways to capture the snapper at the corner of its jaws. Young sharks feed on small fishes, shrimps, and crabs. Caribbean reef sharks are capable of everting their stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
s, which likely serves to cleanse indigestible particles, parasites, and mucus from the stomach lining.
Life history
Reproduction is viviparous; once the developing embryoEmbryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s exhaust their supply of yolk, the yolk sac
Yolk sac
The yolk sac is a membranous sac attached to an embryo, providing early nourishment in the form of yolk in bony fishes, sharks, reptiles, birds, and primitive mammals...
develops into a placenta
Placenta
The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...
l connection through which they receive nourishment from their mother. Mating is apparently an aggressive affair, as females are often found with biting scars and wounds on their sides. At the Fernando de Noronha Archipelago and Atol das Rocas off Brazil, parturition takes place at the end of the dry season
Dry season
The dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year...
from February to April, while at other locations in the Southern Hemisphere, females give birth during the Amazon
Amazon Rainforest
The Amazon Rainforest , also known in English as Amazonia or the Amazon Jungle, is a moist broadleaf forest that covers most of the Amazon Basin of South America...
summer in November and December. The average litter size is four to six, with a gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
of one year. Females become pregnant every other year. The newborns measure no more than 74 cm (29 in) long; males mature sexually at 1.5–1.7 m (60–66 in) long and females at 2–3 m (79–116 in).
Human interactions
Normally shy or indifferent to the presence of divers, the Caribbean reef shark has been known to become aggressive in the presence of food and grows sufficiently large to be considered potentially dangerous. As of 2008, the International Shark Attack FileInternational Shark Attack File
The International Shark Attack File is a global database of shark attacks. It began as an attempt to catalogue shark attacks on servicemen during World War II. The Office of Naval Research funded it from 1958 until 1968. During that time a panel of shark experts developed a standard system for...
lists 27 attacks attributable to this species, 4 of them unprovoked, and none fatal.
This species is taken by commercial
Commercial fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often pursue fish far into the ocean under adverse conditions...
and artisanal
Artisan fishing
Artisan fishing is a term used to describe small scale low-technology commercial or subsistence fishing practices. The term particularly applies to coastal or island ethnic groups using traditional techniques such as rod and tackle, arrows and harpoons, throw nets and drag nets, and traditional...
longline and gillnet
Gillnet
Gillnetting is a common fishing method used by commercial and artisanal fishermen of all the oceans and in some freshwater and estuary areas. The gillnet also is used by fisheries scientists to monitor fish populations. Because gillnets can be so effective their use is closely monitored and...
fisheries throughout its range. It is valued for meat, leather, liver oil
Shark liver oil
Shark liver oil is obtained from sharks that are caught for food purposes and are living in cold, deep oceans. The liver oil from sharks has been used by fishermen for centuries as a folk remedy for general health...
, and fishmeal. The Caribbean reef shark is the most common shark landed in Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
(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
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
on hook-and-line intended for grouper
Grouper
Groupers are fish of any of a number of genera in the subfamily Epinephelinae of the family Serranidae, in the order Perciformes.Not all serranids are called groupers; the family also includes the sea basses. The common name grouper is usually given to fish in one of two large genera: Epinephelus...
s and snapper
Lutjanidae
Snappers are a family of perciform fish, mainly marine but with some members inhabiting estuaries, feeding in freshwater. Some are important food fish. One of the best known is the red snapper....
s; the fins are sold to the lucrative Asian market and the meat sold in Belize, Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, and Guatemala
Guatemala
Guatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...
to make "panades", a tortilla
Tortilla
In Mexico and Central America, a tortilla is a type of thin, unleavened flat bread, made from finely ground maize...
-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
Methylmercury
Methylmercury is an organometallic cation with the formula . It is a bioaccumulative environmental toxicant.-Structure:...
and other heavy metals.
Shark feeding
A profitable ecotourism industry has arisen around this species involving organized "shark feeds", in which groups of reef sharks are attracted to divers using bait. Some US$6,000,000 is spent annually on shark viewing in the Bahamas, where at some sites a single living Caribbean reef shark has a value between US$13,000 and US$40,000 (compared to a one-time value of US$50–60 for a dead shark). This practice has drawn controversy, as opponents argue that the sharks may learn to associate humans with food, increasing the chances of a shark attack, and that the removal of reef fishes for bait may damage the local ecosystem. Conversely, proponents maintain that shark feeds contribute to conservation by incentivizing the protection of sharks and educating people about them. Thus far, there has been little evidence that shark feeds have increased the risk of attack in the surrounding area.Murch, A. Shark Feeding. Elasmodiver.com. Retrieved on February 14, 2009 Shark feeding has been outlawed off the coast of Florida, but continues at other locations in the Caribbean.Conservation
The International Union for Conservation of Nature (IUCN) has assessed the Caribbean reef shark as Near ThreatenedNear Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
; its population has declined off Belize and Cuba from overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
and exploitation continues in other regions. They are also threatened by the degradation and destruction of their coral reef habitat. Commercial fishing for this species is prohibited in United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
waters. They are protected in the Bahamas due to their significance to ecotourism, as well as in a number of Marine Protected Area
Marine Protected Area
Marine Protected Areas, like any protected area, are regions in which human activity has been placed under some restrictions in the interest of conserving the natural environment, it's surrounding waters and the occupant ecosystems, and any cultural or historical resources that may require...
s (MPAs) off Brazil and elsewhere. However, enforcement against illegal fishing is lacking in some of these reserves, and many areas in which this species is abundant are not yet protected.