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Blue shark - Prionace glauca

Widespread throughout the world’s temperate and tropical waters, the blue shark is a pelagic species that is usually encountered in the open ocean but can be spotted inshore where the continental shelf is narrow. It can be found from the surface (in cooler waters) to a depth of approximately 1148 ft (in more tropical areas) and is highly migratory; its movements seem to be based on reproduction and prey distribution. The blue shark’s diet consists mostly of cephalopods, crustaceans and bony fishes, but it is also known to consume sea birds and cetaceans (possibly as carrion). Its colouration - deep blue on the dorsal side and bright white underneath - is camouflage in the open ocean and referred to as countershading. It is viviparous, with females delivering an average of 35 pups per litter (although the maximum recorded litter size was 135 pups) after a 9-12 month gestation. The skin of the female is three times thicker than that of the male, as the blue shark’s courtship involves extensive biting from the latter. Adults can reach about 12.5 ft in length at their maximum. Though the blue shark is not a species targeted by commercial fisheries, it is frequently caught as bycatch: It is estimated that 10-20 million blue sharks are killed annually. It is also sought after by sport fishermen, and is currently classed as Near Threatened by the IUCN.

Lemon shark - Negaprion brevirostris

Found along the tropical and subtropical parts of the Atlantic and Pacific coasts of both North and South America as well as Africa’s Ivory Coast, the lemon shark’s name is derived from its coloration, which can appear a pale yellow. It is perfectly camouflaged for swimming over the sandy sea floor while hunting for bony fish and crustaceans, although it is also known to feed on sea birds, rays, and smaller sharks. Fully grown adults reach approximately 8-10ft in length. It is viviparous, with females giving birth to a litter numbering between 4-17 pups every other year after a 10-12 month gestation; the pups stay in and around the shallow “nursery grounds” in which they were born for several years before venturing further. The lemon shark is targeted by commercial and recreational fishermen and is particularly sought after for its fins, which fetch a high price in the shark fin trade. It is currently listed as Near Threatened by the IUCN.

Chain catshark (Chain dogfish) - Scyliorhinus retifer

Found in the western Atlantic from Massachusetts to Nicaragua, the chain catshark is common throughout its range but rarely encountered due to its usual depth, which is around 120-750 feet in the north and deeper than 1,500 feet in the south. Like most species in the Scyliorhinidae family it is a small species, with adult females growing no larger than 1.7 ft long. During the day it can be observed resting on the rocky bottom, often close to man-made objects such as cables. It is a bottom feeder with a diet consisting of squid, bony fish, polychaete worms, and crustaceans. In 2005 Dr. Mikhail Matz, a professor of marine biology at the University of Florida, was the first to identify and document the chain catshark’s previously unknown fluorescent properties; it is still unclear what purpose this serves.

Spinner shark - Carcharhinus brevipinna

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A remarkable hunting technique of this active, fast-swimming shark gives it its common name: it will speed upward through a school of fish with its mouth open while spinning on its axis, emerging completely from the water.Although the maximum known size is known to be 10 feet, the average adult attains a length of just over 6 feet. Found in subtropical and warm temperate waters around the world except the eastern Pacific, the spinner shark forms schools, and the northwest Atlantic population migrates inshore during the summer months to feed and reproduce. Because of confusion with the blacktip shark, there is some uncertainty in the distribution data for this species. Throughout its range, particularly in the southeastern United States, the spinner shark is considered Near Threatened by the IUCN due to its popularity among recreational and commercial fisheries; it is prized for its fins, liver oil, flesh, and skin.

Swellshark - Cephaloscyllium ventriosum

Native to coastal waters in the Eastern Pacific from central California to Chile, the swellshark is a nocturnal species that rests among the rocky reef during the day and hunts fish, crustaceans and molluscs at night. Adults reach an average length of about 3ft and are oviparous, with the female depositing only two egg sacks at a time among a rocky, algal-covered habitat. When threatened, it bends its body and grabs its caudal fin in its mouth before swallowing a large amount of water to double its size, making it difficult for a potential predator to bite or remove it from a crevice. It is also able to do this same behaviour with air if brought to the surface, and will let out a dog-like bark when expelling the swallowed water or air.