image by chris gotschalk
Basking sharks are social animals and form sex-segregated schools, usually in small numbers (three or four), but reportedly up to 100 individuals. Their social behaviour is thought to follow visual cues. Although the basking shark’s eyes are small, they are fully developed. They may visually inspect boats, possibly mistaking them for conspecifics. Females are thought to seek shallow water to give birth.
image by peter halasz
Goblin sharks feed on a variety of organisms that live in deep waters. Among some of their known prey are deep-sea squid, crabs, and deep-sea fish. Very little is known about the species’ life history and reproductive habits, as encounters with them have been relatively rare. As seemingly rare as they are however, there seems to be no real threat to their populations and so they are not classified as endangered species by the IUCN.
image by opencage
The appearance of the megamouth is distinctive, but little else is known about it. It has a brownish-black colour on top, is white underneath, and has an asymmetrical tail with a long upper lobe, similar to that of the thresher shark. The interior of its gill slits are lined with finger-like gill rakers that capture its food. A relatively poor swimmer, the megamouth has a soft, flabby body and lacks keels.
Whitetip Reef Shark
image by richard ling
Whitetip reef sharks are rarely aggressive towards humans, though they may investigate swimmers closely. However, spear fishers are at risk of being bitten by one attempting to steal their catch. This species is caught for food, though ciguatera poisoning resulting from its consumption has been reported. The IUCN has assessed the whitetip reef shark as Near Threatened, noting its numbers are dwindling due to increasing levels of unregulated fishing activity across its range. The slow reproductive rate and limited habitat preferences of this species renders its populations vulnerable to overfishing.
image by sigmund
Zebra sharks are nocturnal and spend most of the day resting motionless on the sea floor. At night, they actively hunt for molluscs, crustaceans, small bony fishes, and possibly sea snakes inside holes and crevices in the reef. Though solitary for most of the year, they form large seasonal aggregations. The zebra shark is oviparous: females produce several dozen large egg capsules, which they anchor to underwater structures via adhesive tendrils. Innocuous to humans and hardy in captivity, zebra sharks are popular subjects of ecotourism dives and public aquaria. The World Conservation Union has assessed this species as Vulnerable worldwide, as it is taken by commercial fisheries across most of its range (except off Australia) for meat, fins, and liver oil. There is evidence that its numbers are dwindling.
image by david
The blind shark has a stocky body and a wide, somewhat flattened head with a blunt snout. The small, oval eyes are situated high on the head and have strong ridges underneath; the oval spiracles are positioned behind and below and have obvious raised rims. The nostrils are placed almost at the tip of the snout and have long, tapering barbels in front and well-developed skin flaps and grooves around the incurrent openings. A pair of obvious grooves connect the nostrils to the small, almost transverse mouth. There are 32–34 upper tooth rows and 21–29 lower tooth rows; each tooth has an upright, awl-shaped central cusp and a pair of lateral cusplets. The five pairs of gill slits are small, with the fifth pair close to the fourth.
image by chad
Horn sharks are harmless unless harassed, and are readily maintained in captivity. They are not targeted by either commercial or recreational fisheries, though small numbers are caught as bycatch. In Mexico this species is used for food and fishmeal, and in California its spines are made into jewelry. The International Union for Conservation of Nature (IUCN) does not yet have enough information to determine the horn shark’s conservation status. It faces few threats off the coast of the United States.
Spined Pygmy Shark
image by noaa
Usually inhabiting nutrient-rich waters over upper continental and insular slopes, the spined pygmy shark feeds on small bony fishes and squid. Like its prey it is a diel vertical migrator, spending the day at close to 500 m (1,600 ft) deep and moving towards a depth of 200 m at night. Reproduction is presumably aplacental viviparous, with female giving birth to litters of 4 pups. This diminutive shark has no economic value. The International Union for Conservation of Nature (IUCN) has assessed this species as of Least Concern, as it faces little threat from commercial fisheries and has a wide distribution.
image by asobi
The kitefin shark has a moderately elongated body with a very short, rounded snout. The eyes and spiracles are large. The lips are thick with pleats or fringes, though are not modified to be suctorial. There are 16–21 tooth rows in the upper jaw and 17–20 tooth rows in the lower jaw. The upper teeth are small and spike-shaped, curving slightly towards the corners of the mouth. The lower teeth are very large, knife-shaped, and serrated, with their bases interlocking to form a continuous cutting surface.
image by own
The frilled shark is one of two extant species of shark in the family Chlamydoselachidae, with a wide but patchy distribution in the Atlantic and Pacific Oceans. This uncommon species is found over the outer continental shelf and upper continental slope, generally near the bottom though there is evidence of substantial upward movements. It reaches a length of 2 m (6.6 ft) and has a dark brown, eel-like body with the dorsal, pelvic, and anal fins placed far back. Its common name comes from the frilly or fringed appearance of the gill slits, of which there are six pairs with the first pair meeting across the throat.
Smooth Hammerhead Shark
image by discovery
The smooth hammerhead is an active-swimming predator that feeds on bony fishes, rays, sharks , cephalopods, and to a lesser extent crustaceans such as shrimp, crabs, and barnacles. Off South Africa, smooth hammerheads feed on squid such as Loligo vulgaris and small schooling fish such as pilchard over the deep coral reefs at the edge of the continental shelf, with individuals over 2 m (6.6 ft) long taking increasing numbers of smaller sharks and rays. Off Australia, squid are the most important prey, followed by bony fish.
Bigeye thresher Shark
image by piro
The eyes of the bigeye thresher can measure up to 10 cm across in adults. Each eye is taller than wide, with a bulbous upper portion. The orbits extend onto the dorsal surface of the head, allowing the eyes to orient upwards.The snout is moderately long and bulbous, and there are no labial furrows at the corners of the mouth. The teeth are moderately large with a single, narrow cusp. There are large and small dermal denticles, with the smaller ones more numerous and interspersed amongst the larger ones. The smaller denticles taper to a point.