SHARKS & RAYS OF BIMINI
BIGEYE SIXGILL SHARK
Description: Slender-bodied, deep water shark. As the common name implies, the bigeye sixgill has notably large eyes and six gills rather than the usual 5 found on many shark species. It exhibits a sharp contrast of countershading between dorsal and ventral sides of the body.
Distribution and Habitat: Occurs in tropical or warm temperate deep waters in small, patchy areas across the globe. Typically found on or near sea floor on continental or island shelves at depths between 90 to 621 meters.
Size: Max size is about 180 cm.
Reproduction: Viviparous. Litter size ranges between 13 to 26 pups. Females typically reach sexual maturity at 142-178 cm and males mature at 123 to 157 cm total length.
Diet: small to medium-sized bony fishes and crustaceans.
Status: Data deficient.
Human pressures: occasionally caught as bycatch in some fisheries. Not commercially important.
Description: Typical Carcharhinid-shaped body with a black tip on snout. Second dorsal fin tip and upper caudal fin tip also darkened. No interdorsal ridge, small pectoral fins. Second dorsal fin located directly above anal fin.
Distribution and Habitat: Occurs in the warm temperate and tropical waters of the Western Atlantic as far north as southern USA and as far south as southern Brazil. Found in coastal waters on continental and insular shelves. Habitat is typically sand, shell and coral substrates between depths of 18-64 meters.
Size: Max size is 137 cm total length. Size at birth is 31-50 cm total length.
Reproduction: Viviparous with a yolk-sac placenta, litters of 1 to 6 pups born every 1-2 years. Gestation period of 10 to 11 months. Females typically reach maturity at or 101-120 cm total length, males mature at 97-110 cm total length, around 2-4.5 years for both males and females.
Life span: Lives for about 12.5-15 years depending on region.
Diet: Small fishes.
Human pressures: Captured and retained as bycatch in longlines, gillnets, trawls, and hook and line causing a significant decline in population
Description: Grey-brown in color with white counter shading on ventral side. Prominent white band along flank. Black markings usually found on first and second dorsal, pectoral, pelvic, anal, and lower caudal fin tips, although some adults lack black markings. Other characteristics include small eyes, long gill slits, and a long, narrow pointed snout. No interdorsal ridge present.
Distribution and Habitat: Occurs in warm temperate, subtropical, and tropical waters typically around continental shelves, although it is occasionally found around oceanic islands. Blacktips typically inhabit coastal waters around estuaries, shallow muddy bays, saline mangrove swamps, island lagoons and coral reef drop-offs. While they are not found in freshwater, they are able to tolerate reduced salinity. Rarely found in water deeper than 30 meters.
Size: Maximum recorded size is 255 cm total length. Size at birth is typically 38-72 cm total length.
Reproduction: Viviparous with a yolk-sac placenta. Litter size of 1-11 pups, usually 4-7. Gestation period of 10-12 months during alternate years. The size at which males and females reach sexual maturity is dependent on location. Generally, females will mature around 150-156 cm total length (6-7 years), and males will reach maturity at 130-145 cm total length (4-5 years).
Life span: lives for about 9-10 years.
Diet: Boney fishes, cephalopods and crustaceans such as shrimp and crabs.
Status: Near threatened.
Human pressures: a targeted species by both recreational and commercial fisheries in the western North Atlantic for its meat and fins.
Description: Large, stout bodies with a broad head and small eyes. Greyish in color with a white underside. Dusky fin tips mostly prominent in juveniles. Large angular pectoral fins, triangular first dorsal fin, and a small second dorsal fin. No interdorsal ridge present.
Distribution and Habitat: Occurs in tropical and warm temperate waters with seasonal occurrences in cool temperate waters. Found in both salt and freshwaters. Inhabits coastal inshore waters on continental and occasionally insular shelves as well as estuaries and freshwaters such as rivers. Typically found in waters 0-30 meters deep but have been observed at depths of 150 meters.
Size: Maximum size of 340 cm total length. Size at birth is 56-81 cm total length.
Reproduction: Viviparous with a yolk-sac placenta. Litter size of 1-13 pups born in estuaries and rivers after a gestation period of 10-11 months. Males reach sexual maturity at 157-226 cm total length, and females mature at 180-230 cm total length.
Life span: maximum age is estimated to be around 27 years.
Diet: Very diverse diet consisting of bony fishes and other teleosts, smaller elasmobranchs, turtles, birds, dolphins, crustaceans and other animals that are small enough for a bull shark to eat.
Status: Near threatened.
Human pressures: Because the bull shark is euryhaline, its presence in both fresh- and saltwater means that it is subject to increased human-induced environmental changes across habitats. Bull sharks are caught in commercial and recreational fisheries primarily as a bycatch species although they are occasionally targeted and killed for their fins.
CARIBBEAN REEF SHARK
Description: large dark grey or grey-brown reef shark with white countershading on ventral side. Dusky edges on undersides of paired fins, anal and ventral caudal lobe. Short, blunt snout. Large pectoral fins, small first dorsal fin, and relatively large second dorsal fin located slightly ahead of the anal fin. Interdorsal ridge present.
Distribution and Habitat: Occurs in Atlantic tropical inshore waters, ranging from the southeastern coast of the United States (North Carolina) to Brazil. Commonly found on coral reefs on continental and insular shelves across a wide depth range, usually ranging at depths between 1-35 meters, but can be found at depths up to 378 meters.
Size: max size 295 cm total length. Size at birth is approximately 70cm total length.
Reproduction: Viviparous with a yolk-sac placenta. Litter size is between 3-6 pups. Gestation period is approximately 1 year on a biennial cycle. Males typically reach sexual maturity at 150-170 cm total length, and females mature around 180-190 cm total length.
Life span: estimated maximum age of 15 years.
Diet: mainly bony fish, crustaceans and cephalopods
IUCN Status: Endangered as of July 2019
Human pressures: Targeted and caught as bycatch in commercial and recreational fisheries that utilize longlines and gillnets causing population decline. Climate change impacting coral reefs are causing Caribbean reef sharks to lose their primary habitat for protection from fishing and foraging.
GREAT HAMMERHEAD SHARK
Description: Light grey or grey-brown in color with white ventral countershading. Very large cephalofoil (hammerhead) with a notch at the center of its head. Tall, large first dorsal fin, small second dorsal with long trailing edge.
Distribution and Habitat: Population distributed worldwide in tropical and warm temperate waters. Occurs in coastal-pelagic and semi-oceanic waters. Found around continental shelves, island terraces, lagoons, and coral reefs both close to and far off shore. Depth can range from 0-300 meters.
Size: Maximum size reported at 610 cm total length, more commonly observed max size of around 400 cm total length. Size at birth is typically 50-70 cm total length.
Reproduction: Aplacental viviparity with litter sizes of 6-42 pups. Gestation period is 11 months on a biennial cycle. Males have been found to reach sexual maturity around 225-269 cm total length, and females mature around 210-300 cm total length.
Life span: Estimated at 44 years in the Northwest Atlantic.
Diet: Primarily feeds on batoids such as southern stingrays (Hypanus americanus) and spotted eagle rays (Aetobatus narinari), as well as bony fishes.
IUCN Status: Critically endangered.
Human pressures: Targeted and caught as bycatch globally in commercial and small-scale fisheries by many different gear types: longline, purse seine, gillnets, and trammel nets. Great hammerheads are usually retained for their fins unless prohibited. At-vessel and post-release mortality rate is high for this species regardless of method of capture.
Description: Pale yellow-brown coloration. Big, stocky and short-nosed. First and second dorsal fin of similar size. Flattened head and smooth cusped teeth.
Distribution and Habitat: Occurs in tropical, subtropical, and warm temperate waters of the western Atlantic from Virginia (United States) to Brazil, northeast Atlantic (west Africa) and east Pacific (Mexico to Ecuador). Adult lemon sharks are demersal and pelagic in shallow inshore waters around coral reefs and mangrove fringes. Juveniles are known to remain in nurseries along shallow beaches, seagrass flats, piers, docks and around mangroves for years for ease of foraging and protection against predation. Their home range increases with size and they tend to venture into deeper waters as they grow larger. Their depth range has been observed as 0-92 meters.
Size: max size of 340 cm total length. Size at birth between 60-65 cm total length.
Reproduction: Placentotrophic viviparous with litter sizes of 4-17 pups. Gestation period of 10-12 months on an annual cycle. Sexual maturity is reached around 224 cm total length (11.6 years) for males and 239 cm total length (12.7 years) for females.
Life span: Estimated maximum of 37 years.
Diet: Feeds on fishes, crustaceans and mollusks.
Status: near Threatened
Human pressure: Caught as both as a target and bycatch in commercial and artisanal fisheries on longline and gillnet gear types. Large size and slow life history make its population susceptible to fishing. Mangrove removal adds habitat destruction to the threats facing lemon sharks, as mangrove nurseries are a key habitat for juvenile lemon sharks.
Description: A giant ray with a broad head and large head fins protruding forward. Predominantly black dorsal side, occasionally with white patches between head and wings. Ventral side predominantly white with grey blotches which can be used for individual identification.
Distribution and Habitat: Population of giant mantas is found around the globe in tropical and temperate waters. Occurs in neritic and oceanic pelagic zones, particularly where upwelling occurs such as coast lines, oceanic islands and seamounts. Presents patterns of diel habitat use, feeding at depths up to 1000 meters at night and moving into the shallows (up to 0 meters) during the day.
Size: Maximum recorded size at 700 cm disc width. Size at birth of 122-200 cm disc width.
Reproduction: Aplacental viviparous. Litter size consists of one pup after a gestation period of 12-13 months. Female reproductive periodicity is unknown, but assumed to occur every 4-5 years. Females reach sexual maturity around 380-500 cm disc width, and males mature around 350-400 cm disc width.
Life Span: Estimated to be about 45 years based on the life span of the reef manta ray (Mobula alfredi).
Diet: Zooplankton and krill.
Status: Endangered as of November 2019.
Human Pressures: Both targeted and caught as bycatch in commercial and artisanal fisheries. Diel movements and the highly migratory nature of giant manta rays makes them highly susceptible to being caught in fishing gear such as purse seines, longlines, gillnets and driftnets. When caught as bycatch, they are typically retained due to high market value.
Description: Gray-brown coloration and white underbelly with a long, pointed snout. Front of the small first dorsal fin that begins over its small pectoral fins. Both dorsal fins are small with long trailing edges. Distinguished by its large eyes. Interdorsal ridge present.
Distribution and Habitat: Found in the western Atlantic from Delaware (US) to Argentina. Found rarely in the eastern Atlantic along the west coast of Africa. Occurs in mostly deepwater pelagic and oceanic regions near outer continental shelves from depths of 0 m to 600 m.
Size: Maximum length of 276 cm total length. Size at birth ranges from 60-72 cm total length.
Reproduction: Placental viviparity with a yolk-sac placenta. Litter size of 4-15 pups with an average of 11 pups. Males reach sexual maturity around 185-190 cm total length; females mature at 200-205 cm total length.
Lifespan: 25 years.
Diet: Small, active bony fishes, squid and shrimp.
IUCN Status: Endangered as of June 2019.
Human Pressures: Caught as bycatch primarily on pelagic longlines set by commercial fisheries. While the night shark is not a targeted species, bycatch is often retained due to their valuable fins. At their southern range, they are subject to fishing pressure from unmanaged artisanal fisheries. Catch from longlines and gillnets result in high mortality upon capture, with as large as 76% mortality from pelagic longlines.
Description: Adults are yellow- to grey- brown in color. Mouth area includes long barbels and nasal grooves, located in front of dorsolateral eyes. Tiny spiracles located behind eyes. Broadly rounded dorsal fins, first dorsal located close to second dorsal fin. Caudal fin consists of only dorsal lobe and makes up 25% of total body length. Small gill slits, 5th almost over laps 4th.
Distribution and Habitat: Widely distributed in tropical and subtropical waters of the Atlantic ocean. In the western Atlantic it ranges from North Carolina (USA) to southern Brazil, including the Gulf of Mexico and Caribbean sea. Occurs in the eastern Atlantic from Morocco to Angola. Found on Rocky and coral reefs, channels between mangrove keys and sand flats on continental and insular shelves. Found at depths of 0-130 meters.
Size: Maximum size recorded at 308 cm total length. Size at birth around 30 cm total length.
Reproduction: Viviparous form of reproduction. Litter size is around 20-30 pups after a gestation period of 5-6 months. Broods are born biennially in late-spring to summer. Males reach sexual maturity at 210 cm total length; Females mature between 230 and 240 cm total length.
Life span: 35 years.
Diet: bottom dwelling fish and some benthic invertebrates such as lobster or queen conch. Their specialized mouth equipped with powerful suction and crushing plate is used to invertebrates them from their shells.
Status: Vulnerable as of July 2019.
Human pressures: Targeted or caught as bycatch in commercial, artisanal and recreational fisheries on longlines, gillnets, trawls, and beach seines. Vulnerable to overexploitation in unmanaged fisheries. Human impacts causing habitat degradation on coral reefs, seagrass beds, or mangrove removal also poses threats to the Atlantic nurse shark population.
Description: Dark grey to grey-brown or nearly black dorsal side, pale flank band and white ventral side. Inconspicuous fin markings including dusky edges on ventral caudal lobe, second dorsal, pectoral, pelvic and anal fins. Large and slim body with a long, flat rounded snout and small jaws. Long narrow pectoral fins located in front of first dorsal fin. Narrow interdorsal ridge present.
Distribution and Habitat: Occurs worldwide in all tropical and some warm temperate waters. Ranges from Massachusetts (USA) to southern Brazil in the western Atlantic. The silky shark is an oceanic and coastal pelagic species frequently found along edges of continental and insular shelves. Most common in water less than 200 meters deep, although it can be found at depths of 500 meters in epipelagic zones.
Size: Maximum size varies among regions, but has recorded as 371 cm total length in the Atlantic. Size at birth is typically 65-81 cm total length.
Reproduction: Viviparous live birth after a gestation period of 9-12 months (varies depending on region). Litter size ranges from 2-18 pups, with an average of 5-7. In the Atlantic, males have been shown to reach sexual maturity between 215-225 cm total length, and females will reach maturity between 232-246 cm total length.
Life span: Varies by region, estimated at 22 years in the Atlantic.
Diet: As adults, silky sharks can be seen swimming with and feeding on schools of tuna. Their diet also includes other teleosts, cephalopods and pelagic crabs.
Status: Vulnerable as of September 2017.
Human pressures: Second most caught species of shark globally. Targeted or caught as bycatch in commercial and artisanal fisheries by longlines, purse seines and nets set in the water column. Often retained (regulations permitting) for fins and meat trade.
Description: Brown- to light sand-colored body. The most distinguishing feature of a smalltooth sawfish is its long blade-like rostrum with anywhere between 24-32 pairs of teeth on the sides. First dorsal and second dorsal fin of similar shape and size. First dorsal located above pelvic fins. No ventral lobe on caudal fin.
Distribution and Habitat: Distributed in tropical and subtropical waters of the western Atlantic and certain areas along the coast of the eastern Atlantic. Habitat range is expected to have decreased over time as the species population declined. Found in coastal and estuarine waters, usually around inshore mangrove and seagrass habitats. Occur at depths 0.1-88 meters; smaller individuals will spend more time at shallower depths and descend as they grow larger.
Size: Maximum recorded size is 760 cm total length, although a recent study in the Atlantic reported a maximum size of about 500 cm total length. Size at birth estimated at 64-81 cm total length.
Reproduction: Lecithotrophic viviparous. Litter size of 7-14 pups born biennially after a 12 month gestation period. Females have been observed to reach sexual maturity at 370 cm total length; males mature at 340 cm total length.
LIfe Span: Maximum age estimated at 30 years.
Diet: Bony fish, crustaceans and other marine invertebrates.
Status: Critically Endangered as of May 2012.
Human Pressures: Smalltooth sawfish currently face threats associated with bycatch from various fisheries. Although they are no longer a legally targeted species in the USA, their rostrum and large size make them highly susceptible to entanglement in fishing gear, primarily net-based gear. Habitat degradation of mangroves and seagrass beds compound the threats to their population decline.
Description: Light brown, grey or olive coloration on the dorsal side with a white ventral side with some dusky margins. Snout forms a small triangular protuberance on a rhomboidal shaped body (disc). Irregular row of short spines along the center of the dorsal side from around the disc center to tail. Large spiracles located directly behind eyes. Unlike some other stingray species, southern stingrays do not have very noticeable tubercles or thorns along their tail.
Distribution and Habitat: Found along the eastern coast of North America, Central America, and South America in both the Gulf of Mexico and the Caribbean Sea. Usually found on sandflats near seagrass beds and coral reefs between depths of 0-100 meters.
Size: Maximum size of 150 cm disc width (DW). Size at birth of 17-19 cm disc width.
Reproduction: Viviparous. Litter size of 2-10 pups after a gestation period of 5-8 months. Females reach sexual maturity at approximately 75 to 80 cm disc width while males reach maturity at 52 cm disc width.
Life span: Maximum recorded age of 17 years in the wild.
Diet: Crustaceans and teleosts.
IUCN Status: Near Threatened, Decreasing
Human Pressures: Caught as bycatch in commercial and artisanal fisheries by trammel nets, gillnets, beach seines and longlines. Interaction with tourism through food provisioning has caused behavioral shifts that interrupt diel behaviors, possibly exposing them to additional predatory risk. Habitat degradation of mangroves, seagrass beds and coral reefs pose a threat to this species.
SPOTTED EAGLE RAY
Description: Diamond-shaped pectoral disc with a protruding, flattened snout. Deep blue or black pectoral side with white spots, rings and dashes distributed throughout. Ventral side is white with some grey patches. Pectoral wings extend nearly twice as wide as they are long, with angled lateral edges. Snout is shaped like a beak or a shovel. Small dorsal fin located at the base of the tail, slightly in front of stinging spines. Whip-like tail that can be up to three times as long as the width of the pectoral disc.
Distribution and Habitat: Found throughout the Atlantic ocean in tropical to warm temperate waters. On the western side of the Atlantic, whitespotted eagle rays range from North Carolina (USA) to Rio de Janeiro (Brazil). Benthopelagic species found over the continental shelf, often occurs in lagoons, estuaries, coral reefs and open water. Depth ranges from 0 m to 60 m.
Size: Maximum recorded size is 230 cm disc width. Size at birth of 18-36 cm disc width.
Reproduction: Matrotrophic viviparous. Litter size of 1-5 pups with a gestation period of 12 months. Males mature at a disc width of 127-129 cm, while females mature at a disc width of 134.9 cm.
Diet: Worms, bivalve and gastropod mollusks, cephalopods, crustaceans and fish.
IUCN Status: Endangered as July 2020.
Human Pressures: Caught as bycatch in commercial and artisanal fisheries on net-like fishing gear such as gillnets. Throughout their range, some areas have a lack of fisheries restrictions, resulting in higher catch rates due to overexploitation. They are a popular aquarium species so are at risk from aquarium trade. Additional threats include pollution, dredging, and habitat loss.
Description: Grey dorsal side with dark grey or black vertical stripes and spots; white ventral side for countershading. Markings fade as with increased size. Large body with a bluntly rounded snout and large, black eyes. Fourth and fifth gill slits located over pectoral fins. Prominent interdorsal ridge.
Distribution and Habitat: Occurs globally in tropical and warm temperate waters. Some populations have shown seasonal migration into cool temperate waters. In the western Atlantic, the species ranges from Massachusetts (USA) to Uruguay including the Gulf of Mexico and the Caribbean. A highly migratory species, tiger sharks can be found over continental and insular shelves on coral reefs, seagrass beds, sandflats and occasionally far into the pelagic zone. Occurs at depths from 0-1136 meters.
Size: Maximum recorded size of 740 cm total length, typically no larger than 500 cm total length. Size at birth is 51-90 cm total length.
Reproduction: Lecithotrophic viviparous with a 15-16 month gestation period.. Litter size is typically 26-33 pups (largest recorded litter size is 82 pups). Reproductive cycle has been observed to be triennial.
Lifespan: Estimated maximum age of 27-37 years.
Diet: Diet variability increases ontogenetically with size. Common prey includes teleosts, sea turtles, dolphins and smaller elasmobranchs.
IUCN Status: Near threatened as of August 2018.
Human pressures: Targeted and caught as bycatch in commercial, artisanal and recreational fisheries around the world, often on baited longlines or drumlines. Tiger sharks are occasionally targeted as part of the shark fin trade. In Australia, tiger sharks are targeted as part of the shark control program aimed at keeping large sharks from popular beaches.
Description: Reticulated dark green/ brownish spots against a pale background or lighter spots against a dark background. Round disc with no angular edges or dorsal fin. Venomous spine located before the well-developed caudal fin at the tip of its relatively thick tail.
Distribution and habitat: Found as far north in the western Atlantic as North Carolina (USA) and as far south as Guyana in South America including the Gulf of Mexico and the Caribbean sea. Found on continental and insular shelves in shallow water. Commonly found on habitats such as near coral reefs, sand or muddy flats, and seagrass beds. Depth range of 1-70 meters.
Size: Maximum size is 76 cm total length. Size at birth unknown.
Reproduction: Viviparous with biennial reproductive cycle. Litter size of 1-5 pups. Both males and females are believed to reach sexual maturity at 20 cm total length.
Diet: Polychaete worms, benthic crustaceans such as crabs, molluscs and some bony fish.
Life span: Maximum age estimated at 14 years.
Status: Least Concern as of Jun 2019.
Human pressures: Threatened by habitat loss such as coral reef and seagrass bed degradation and other climate change related issues.