How big can a dusky shark get?
Dusky shark
The dusky shark ("Carcharhinus obscurus") is a species of requiem shark, in the 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 a depth of 400 m (1,300 ft). Populations migrate seasonally towards the poles in the summer and towards the equator in the winter, traveling hundreds to thousands of kilometers. One of the largest members of its genus, the dusky shark reaches 4.2 m (14 ft) in length and 347 kg (765 lb) in weight. It has a slender, streamlined body and can be identified by its short round snout, long sickle-shaped pectoral fins, ridge between the first and second dorsal fins, and faintly marked fins.
Great white shark
While these measurements have not been confirmed, some great white sharks caught in modern times have been estimated to be more than long, but these claims have received some criticism. However, J. E. Randall believed that great white shark may have exceeded in length. A great white shark was captured near Kangaroo Island in Australia on 1 April 1987. This shark was estimated to be more than long by Peter Resiley, and has been designated as KANGA. Another great white shark was caught in Malta by Alfredo Cutajar on 16 April 1987. This shark was also estimated to be around long by John Abela and has been designated as MALTA. However, Cappo drew criticism because he used shark size estimation methods proposed by J. E. Randall to suggest that the KANGA specimen was long. In a similar fashion, I. K. Fergusson also used shark size estimation methods proposed by J. E. Randall to suggest that the MALTA specimen was long. However, photographic evidence suggested that these specimens were larger than the size estimations yielded through Randall's methods. Thus, a team of scientists—H. F. Mollet, G. M. Cailliet, A. P. Klimley, D. A. Ebert, A. D. Testi, and L. J. V. Compagno—reviewed the cases of the KANGA and MALTA specimens in 1996 to resolve the dispute by conducting a comprehensive morphometric analysis of the remains of these sharks and re-examination of photographic evidence in an attempt to validate the original size estimations and their findings were consistent with them. The findings indicated that estimations by P. Resiley and J. Abela are reasonable and could not be ruled out. A particularly large female great white nicknamed "Deep Blue", estimated measuring at was filmed off Guadalupe during shooting for the 2014 episode of Shark Week "Jaws Strikes Back". Deep Blue would also later gain significant attention when she was filmed interacting with researcher Mauricio Hoyas Pallida in a viral video that Mauricio posted on Facebook on 11 June 2015. Deep Blue was later seen off Oahu in January, 2019 while scavenging a sperm whale carcass, whereupon she was filmed swimming beside divers including dive tourism operator and model Ocean Ramsey in open water. A particularly infamous great white shark, supposedly of record proportions, once patrolled the area that comprises False Bay, South Africa, was said to be well over during the early 1980s. This shark, known locally as the "Submarine", had a legendary reputation that was supposedly well founded. Though rumors have stated this shark was exaggerated in size or non-existent altogether, witness accounts by the then young Craig Anthony Ferreira, a notable shark expert in South Africa, and his father indicate an unusually large animal of considerable size and power (though it remains uncertain just how massive the shark was as it escaped capture each time it was hooked). Ferreira describes the four encounters with the giant shark he participated in with great detail in his book "Great White Sharks On Their Best Behavior".
Atlantic weasel shark
One of the smaller species of shark, the largest recorded adult Atlantic weasel shark measured only 138cm and weighed 11kg , which is believed to be their maximum size. Feeding primarily on cephalopods, including squid and octopuses, it display slow growth rates as well as late maturity in their lifespan . This shark is considered as a specialist feeder, preying on small bony fishes including soles and sardines in addition to cephalopods . Mating season for this species occurs from March to May, while offspring are released from May to June . These sharks are viviparous and give birth to live young which develop inside the parent’s body with a yolk-sac placenta . It gives birth to 1 to 4 pups per litter, averaging in 47cm in length . While males mature at 80cm in length, females may mature between 75cm and 90cm in length .
Longnose pygmy shark
The longnose pygmy shark ("Heteroscymnoides marleyi") is a rare species of squaliform shark in the family Dalatiidae and the only member its genus. It is known only from a handful of specimens collected from the cold oceanic waters of the Southern Hemisphere, between the surface and a depth of . Reaching in length, this diminutive shark is characterized by a slender, dark brown body with a very long, bulbous snout. In addition, it has two spineless dorsal fins of nearly equal size, with the origin of the first lying over the pectoral fin bases. The longnose pygmy shark does not appear substantially threatened by fisheries, and has been assessed as Least Concern by the International Union for Conservation of Nature (IUCN).
Dusky shark
The known diet of the dusky shark encompasses pelagic fishes, including herring and anchovies, tuna and mackerel, billfish, jacks, needlefish and flyingfish, threadfins, hairtails, lancetfish, and lanternfish; demersal fishes, including mullets, porgies, grunts, and flatheads, eels, lizardfish, cusk eels, gurnards, and flatfish; reef fishes, including barracudas, goatfish, spadefish, groupers, scorpionfish, and porcupinefish; cartilaginous fishes, including dogfish, sawsharks, angel sharks, catsharks, thresher sharks, smoothhounds, smaller requiem sharks, sawfish, guitarfish, skates, stingrays, and butterfly rays; and invertebrates, including cephalopods, decapod crustaceans, barnacles, and sea stars. Very rarely, the largest dusky sharks may also consume sea turtles, marine mammals (mainly as carrion), and human refuse.
Grey reef shark
The coloration is grey above, sometimes with a bronze sheen, and white below. The entire rear margin of the caudal fin has a distinctive, broad, black band. There are dusky to black tips on the pectoral, pelvic, second dorsal, and anal fins. Individuals from the western Indian Ocean have a narrow, white margin at the tip of the first dorsal fin; this trait is usually absent from Pacific populations. Grey reef sharks that spend time in shallow water eventually darken in color, due to tanning. Most grey reef sharks are less than long. The maximum reported length is and the maximum reported weight is .
Dusky shark
Because of its slow reproductive rate, the dusky shark is very vulnerable to human-caused population depletion. This species is highly valued by commercial fisheries for its fins, used in shark fin soup, and for its meat, skin, and liver oil. It is also esteemed by recreational fishers. The International Union for Conservation of Nature (IUCN) has assessed this species as Near Threatened worldwide and Vulnerable off the eastern United States, where populations have dropped to 15–20% of 1970s levels. The dusky shark is regarded as potentially dangerous to humans due to its large size, but there are few attacks attributable to it.
Sawshark
The tropical sawshark ("Pristiophorus delicatus") a pale brown with a yellow hew, and an underbelly that is a pale yellow to white. This deep water dwelling fish is located off the Northeastern shore of Australia, in depths up to 176–405 m. It averages in size at about 95 cm. Other than its location and appearance little is known of the creature; it is hard to catch due to its ability to travel into the depths of the ocean.
Blackspot shark
The blackspot shark ("Carcharhinus sealei") is a small species of requiem shark in the family Carcharhinidae found in the tropical Indo-West Pacific Ocean between latitudes 24°N and 30°S, from the surface to a depth around . Its length is a little under one meter (yard) and it is not considered to be dangerous to humans. It feeds mainly on fish, crustaceans, and squid. This shark is also caught in small-scale fisheries for human consumption.
Smooth hammerhead
The second-largest hammerhead shark after the great hammerhead shark, the smooth hammerhead can measure up to long. It is an active predator that takes a wide variety of bony fishes and invertebrates, with larger individuals also feeding on sharks and rays. As in the rest of its family, this shark is viviparous and gives birth to litters of 20–40 pups. A relatively common shark, it is captured, intentionally or otherwise, by many commercial fisheries throughout its range; its fins are extremely valuable for use in shark fin soup. This shark is potentially dangerous and has likely been responsible for a few attacks on humans, though it is less likely to encounter swimmers than other large hammerhead species due to its temperate habitat.
Blurred lanternshark
The blurred lanternshark ("Etmopterus bigelowi") is a little-known species of dogfish shark in the family Etmopteridae, found around the world in benthic and pelagic habitats from a depth of to over down. This shark forms the "E. pusillus" species group with the smooth lanternshark, which are distinguished from other members of its family by having irregularly arranged, flat-topped dermal denticles that give them a "smooth" appearance. Both species are slender-bodied with long heads, two dorsal fins bearing spines, no anal fins, and light-emitting photophores. The blurred lanternshark is larger, reaching or more in length. This species feeds on small squid, fishes, and fish eggs, and is ovoviviparous. It has been assessed as of Least Concern by the International Union for Conservation of Nature, because of its wide distribution and lack of threat from fishing pressure.
Aipysurus duboisii
Aipysurus duboisii, also known as the Dubois' sea snake or reef shallows sea snake, is a species of venomous sea snake. Its geographic range includes Papua New Guinea, New Caledonia and the northern, eastern and western coastal areas of Australia, that is the Coral Sea, Arafura Sea, Timor Sea and Indian Ocean. They live at depths up to 80 meters (262 feet) in coral reef flats, sandy and silty sediments which contain seaweed, invertebrates and corals or sponges that can serve as shelter. These snakes feed on moray eels and various fish that live on the seafloor, up to 110 cm (3.6 feet) in size. They are viviparous, giving birth to live young rather than laying eggs. They have medium aggressiveness, i.e., will bite if provoked, but not spontaneously. The fangs are 1.8 mm long, which are relatively short for a snake, and the venom yield is 0.43 mg. "Aipysurus duboisii" is a crepuscular species, meaning that they are most active at dawn and dusk.
Dusky shark
The dusky shark is a generalist that takes a wide variety of prey from all levels of the water column, though it favors hunting near the bottom. A large individual can consume over a tenth of its body weight at a single sitting. The bite force exerted by a long dusky shark has been measured at over the area at the tip of a tooth. This is the highest figure thus far measured from any shark, though it also reflects the concentration of force at the tooth tip. Dense aggregations of young sharks, forming in response to feeding opportunities, have been documented in the Indian Ocean.
Graceful shark
The pectoral fins are falcate (sickle-shaped) and taper to pointed tips; their leading margins measure about a fifth as long as the total length in sharks over long. The first dorsal fin is high and broad, with a pointed apex and a concave trailing margin; its origin lies roughly over the insertion (the rear of the fin base) of the pectoral fins. The second dorsal fin is relatively large and located about opposite the anal fin, which is about of equal size. There is no ridge between the dorsal fins. The caudal fin has a well-developed lower lobe and a ventral notch near the tip of the upper lobe. This species is bronze above and white below, which extends onto the flanks as a pale stripe. The pectoral fins, dorsal fins, lower caudal fin lobe, and sometimes the pelvic fins usually have black tips, while the upper caudal fin lobe darkens towards the trailing edge and the anal fin may be completely light. The fin markings tend to fade with age. The maximum known length is .
Blue shark
Blue sharks are light-bodied with long pectoral fins. Like many other sharks, blue sharks are countershaded: the top of the body is deep blue, lighter on the sides, and the underside is white. The male blue shark commonly grows to at maturity, whereas the larger females commonly grow to at maturity. Large specimens can grow to long. Occasionally, an outsized blue shark is reported, with one widely printed claim of a length of , but no shark even approaching this size has been scientifically documented. The blue shark is fairly elongated and slender in build and typically weighs from in males and from in large females. Occasionally, a female in excess of will weigh over . The heaviest reported weight for the species was . The blue shark is also ectothermic and it has a unique sense of smell.
Dusky shark
The dusky shark is nomadic and strongly migratory, undertaking recorded movements of up to ; adults generally move longer distances than juveniles. Sharks along both coasts of North America shift northward with warmer summer temperatures, and retreat back towards the equator in winter. Off South Africa, young males and females over long disperse southward and northward respectively (with some overlap) from the nursery area off KwaZulu-Natal; they join the adults several years later by a yet-unidentified route. In addition, juveniles spend spring and summer in the surf zone and fall and winter in offshore waters, and as they approach in length begin to conduct a north-south migration between KwaZulu-Natal in the winter and the Western Cape in summer. Still-larger sharks, over long, migrate as far as southern Mozambique. Off Western Australia, adult and juvenile dusky sharks migrate towards the coast in summer and fall, though not to the inshore nurseries occupied by newborns.
Bignose shark
The long and wide pectoral fins have pointed tips and nearly straight margins. The first dorsal fin originates roughly over the rear of the pectoral fin bases; it is fairly tall and falcate (sickle-shaped), with a blunt apex and a long free rear tip. The second dorsal fin is relatively large with a short free rear tip, and is positioned slightly ahead of the anal fin. A high midline ridge is present between the dorsal fins. The caudal peduncle has a crescent-shaped notch at the origin of the upper caudal fin margin. The caudal fin has a large lower lobe and a strong ventral notch near the tip of the upper lobe. The dermal denticles are closely spaced but non-overlapping, such as that the skin shows between them; each is oval with three horizontal ridges leading to marginal teeth. The coloration is gray to bronze above, with a faint pale stripe on the flank, and white below; sometimes there is a green sheen along the gills. The tips of the fins (except for the pelvic fins) are darker; this is most obvious in young sharks. Males and females grow to at least and long respectively; this species possibly reaches in length. The maximum weight on record is .
Whitespot ghost shark
According to the International Union for Conservation of Nature (IUCN), of the two specimens that were caught and examined, one, a female, had a body length of and a total length of , and the other, a male, had a body length of and a total length of . The male examined was an adult, while the female was not fully grown yet. The chimaera has a single white spot above its pectoral fin about 4–6% the size of its body, after which it is named; aside from this, the chimaera is brown in color. With a tint of blue, its paired fins are darker in the center and lighter on the outside. It is lighter in color in the area behind its pectoral fin and its second dorsal fin. Its width gradually reduces from its body to its narrow tail.
Blind shark
The range of the blind shark is restricted to the eastern coast of Australia, from Mooloolaba in southern Queensland to Jervis Bay in New South Wales; past reports from off Western Australia and Northern Territory appear to be misidentifications of the brownbanded bamboo shark. The blind shark is a bottom-dwelling species that generally inhabits the continental shelf from the intertidal zone, including tidal pools barely deep enough to cover its body, to a depth of , though it has been recorded as deep as . Preferred habitats are rocky areas and adjacent seagrass beds; juveniles are common in high-energy surge zones. In Nelson Bay, this shark has been observed lying in the open atop sponges.
Dusky bushbaby
The dusky bushbaby is a medium-sized galago with a head-and-body length of approximately and a tail of . It weighs around . The face is distinctively marked with a broad pale streak extending from the snout to the fore-head. The large eyes have amber-coloured irises and are surrounded by brownish-black eye rings, outside which is a ridge, particularly obvious on the fore-head. The cheeks are pale grey and the long ears are either black or tipped with black. The upper parts of the body and limbs are dark brown, with a yellowish tinge on the shoulder. The sides of the neck, throat, underparts and underside of the limbs are pale grey. The tail is evenly furred throughout its length and not, or only slightly, bushy, dark grey or greyish-brown, darker towards the tip. The tail is often kept loosely coiled when the animal is at rest, and sometimes when it is in motion. The nails have slightly raised ridges on the upper surfaces and sharp, projecting points. The eye shine of this bushbaby is orange.
Tawny nurse shark
It is found widely along coastlines in the Indo-Pacific, preferring reefs, sandy flats, and seagrass beds from very shallow water to a depth of . With a cylindrical body and a broad, flattened head, the tawny nurse shark is quite similar in appearance to the nurse shark ("Ginglymostoma cirratum") of the Atlantic and East Pacific, from which it can be distinguished by its pointed-tipped dorsal fins and narrow, sickle-shaped pectoral fins. The maximum recorded length of the tawny nurse shark is .
Cookiecutter shark
Like other dogfish sharks, the cookiecutter shark is aplacental viviparous, with the developing embryos being sustained by yolk until birth. Females have two functional uteri and give birth to litters of six to 12 pups. A case has been recorded of a female carrying 9 embryos long; though they were close to the birth size, they still had well-developed yolk sacs, suggesting a slow rate of yolk absorption and a long gestation period. The embryos had developed brown pigmentation, but not the dark collar or differentiated dentition. Newborn cookiecutter sharks measure long. Males attain sexual maturity at a length of , and females at a length of .
Dusky shark
French naturalist Charles Alexandre Lesueur published the first scientific description of the dusky shark in an 1818 issue of "Journal of the Academy of Natural Sciences of Philadelphia". He placed it in the genus "Squalus" and gave it the specific epithet "obscurus" (Latin for "dark" or "dim"), referring to its coloration. Subsequent authors have recognized this species as belonging to the genus "Carcharhinus". Lesueur did not designate a type specimen, though he was presumably working from a shark caught in North American waters.
Dusky shark
As an apex predator positioned at the highest level of the trophic web, the dusky shark is generally less abundant than other sharks that share its range. However, high concentrations of individuals, especially juveniles, can be found at particular locations. Adults are often found following ships far from land, such as in the Agulhas Current. A tracking study off the mouth of the Cape Fear River in North Carolina reported an average swimming speed of . The dusky shark is one of the hosts of the sharksucker ("Echeneis naucrates"). Known parasites of this species include the tapeworms "Anthobothrium laciniatum", "Dasyrhynchus pacificus", "Platybothrium kirstenae", "Floriceps saccatus", "Tentacularia coryphaenae", and "Triloculatum triloculatum," the monogeneans "Dermophthirius carcharhini" and "Loimos salpinggoides", the leech "Stibarobdella macrothela", the copepods "Alebion" sp., "Pandarus cranchii", "P. sinuatus", and "P. smithii", the praniza larvae of gnathiid isopods, and the sea lamprey ("Petromyzon marinus").
Dusky shark
Stocks off the eastern United States are severely overfished; a 2006 stock assessment survey by the U.S. National Marine Fisheries Service (NMFS) showed that its population had dropped to 15–20% of 1970s levels. In 1997, the dusky shark was identified as a Species of Concern by the NMFS, meaning that it warranted conservation concern but there was insufficient information for listing on the U.S. Endangered Species Act (ESA). Commercial and recreational retention of dusky sharks was prohibited in 1998, but this has been of limited effectiveness due to high bycatch mortality on multi-species gear. In addition, some 2,000 dusky sharks were caught by recreational fishers in 2003 despite the ban. In 2005, North Carolina implemented a time/area closure to reduce the impact of recreational fishing. To aid conservation efforts, molecular techniques using polymerase chain reaction (PCR) have been developed that can identify whether marketed shark parts (e.g. fins) are from prohibited species like the dusky shark, versus similar allowed species such as the sandbar shark.
Apparent death
Some sharks can be induced into tonic immobility by inverting them and restraining them by hand, e.g. dogfish sharks, lemon sharks, whitetip reef sharks. For tiger sharks (measuring 3–4 metres in length), tonic immobility can be induced by humans placing their hands lightly on the sides of the animal's snout in the area surrounding the eyes. During tonic immobility in sharks, the dorsal fins straighten, and both breathing and muscle contractions become more steady and relaxed. This state persists for an average of 15 minutes before recovery and the resumption of active behaviour. Scientists have exploited this response to study shark behaviour; chemical shark repellent has been studied to test its effectiveness and to more accurately estimate dose sizes, concentrations and time to recovery. Tonic immobility can also be used as a form of mild anesthesia during experimental manipulations of sharks.
Dusky shark
One of the largest members of its genus, the dusky shark commonly reaches a length of and a weight of ; the maximum recorded length and weight are and respectively. Females grow larger than males. This shark has a slender, streamlined body with a broadly rounded snout no longer than the width of the mouth. The nostrils are preceded by barely developed flaps of skin. The medium-sized, circular eyes are equipped with nictitating membranes (protective third eyelids). The mouth has very short, subtle furrows at the corners and contains 13-15 (typically 14) tooth rows on either side of both jaws. The upper teeth are distinctively broad, triangular, and slightly oblique with strong, coarse serrations, while the lower teeth are narrower and upright, with finer serrations. The five pairs of gill slits are fairly long.
Draughtsboard shark
Most draughtsboard sharks measure no more than long, though rarely an individual may reach ; a recorded maximum size of was probably based on the broadnose sevengill shark ("Notorynchus cepedianus") or some other species. Females grow larger than males. This shark has a stocky, spindle-shaped body that tapers to a relatively thin caudal peduncle. The head is short, broad, and somewhat flattened, with a broadly rounded snout. The nostrils have a triangular flap of skin in front, that do not reach the mouth. The oval eyes have rudimentary nictitating eyelids and are placed somewhat on top of the head; they have thick ridges above and below, and are followed by spiracles. The mouth is very large and curved, without furrows at the corners and with the upper teeth exposed when closed.
Dusky toadlet
The dusky toadlet reaches 30mm in length. It can be dark brown or grey brown with lighter brown variegations or uniform dark brown on the dorsal surface, which is slightly rough and warty. There is normally a pale triangle shape on the head, starting from the eyes. There is a pale yellow patch in the armpit. It has moderate sized parotoid glands. The ventral surface is white with a fair amount of dark blue/black speckling. There is an orange patch in the thighs. The flanks of this species is normally bluish in colour, giving it a dusky appearance. This species is very similar to the smooth toadlet, ("Uperoleia laevigata") and differences between the two are discussed on that page.
Hexanchus
The sixgill sharks are a genus, Hexanchus, of deepwater sharks in the family Hexanchidae. These sharks are characterized by a broad, pointed head, six pairs of gill slits, comb-like, yellow lower teeth, and a long tail. The largest species can grow up to 8 m long and weigh over 600 kg (1320 lb). They are continental shelf-dwelling and abyssal plain scavengers with a keen sense of smell and are among the first to arrive at carrion, together with hagfish and rattails. They show a characteristic rolling motion of the head when feeding. They have been found at depths to . Though only two extant species (the bluntnose sixgill shark and the bigeyed sixgill shark) were originally known, a third, the Atlantic sixgill shark, was found to exist.
Dusky parrot
The dusky parrot is approximately long. It has a medium-wide gray eye-ring (often fades to white in captivity), a splay of cream-white feathers on its upper neck, a pinkish-red tinge to the belly, and red undertail coverts. The remiges and tail are blue, with the latter red at the base. Overall, the dusky parrot is a dark brownish-gray (tending towards black in poor light) bird.
Pondicherry shark
The skin is covered by overlapping dermal denticles; each denticle has three horizontal ridges leading to three (rarely five) marginal teeth. This species is gray above and white below, with an obvious pale stripe on the flanks. The pectoral fins, second dorsal fin, and lower caudal fin lobe are prominently tipped in black, while the first dorsal fin and dorsal caudal fin lobe are narrowly edged in black. The maximum size reached by the Pondicherry shark is uncertain due to a lack of large specimens, but is probably not much greater than .
Sardine run
Swells dropped to 1–1.5 m on 28 June 2011, allowing more netting of sardines. Sardines were netted at Amanzimtoti; on the main beach and at Chain Rocks. A 22-year-old American marine biology student (research diver) named Paulo Edward Stanchi was attacked by a large dusky shark while diving at Aliwal Shoal Marine Protected Area. The group of divers had encountered a pocket of sardines when a 3 m long dusky shark bit Mr Stanchi on his left leg and hands. Mr Stanchi managed to free himself from the shark, and was treated on the diving boat before being transported to Rocky Bay, where medics stabilised him. He was then airlifted to Nkosi Albert Luthuli Hospital, where he underwent surgery. Dusky sharks generally live offshore, but come closer to the shore during the sardine run. The annual sardine run allowed more dusky sharks in the Aliwal Shoal MPA than usual, but there was no reason for them to show any more interest in divers than usual. Mr Stanchi had been wearing split fins with black and grey stripes, and this may have looked like a small shoal of fish to the shark. Meanwhile, a woman in her 40s broke her leg in the frenzy at Amanzimtoti when the sardines were netted. The woman is believed to have been trying to get some of the sardines when she "stepped wrong" and fractured her leg. Paramedics stabilized her before transporting her to hospital.
Prickly shark
Nocturnally active, the prickly shark rests during the day in deeper offshore waters and performs a diel migration to shallower inshore waters at dusk. Individual sharks have a small home range and tend to remain within a given local area. This species consumes a variety of bony and cartilaginous fishes, and cephalopods. Since it moves slowly, it may use suction to capture prey. It is aplacental viviparous, with females producing sizable litters. The prickly shark is not known to be dangerous to humans and has minimal economic value. It is caught incidentally by commercial deepwater fisheries, which are expanding and may potentially threaten its population. Thus, the International Union for Conservation of Nature (IUCN) has assessed this species as Data Deficient.
Oxynotus
Rough sharks are small to medium in size, ranging from in adult body length, depending on species. Their bodies are compressed, giving them a triangular cross-section. They have two large dorsal fins, each with a sharp spine, and with the first fin placed far forward above the head. Even more so than their relatives, the dogfishes, they have rough and prickly skin. Unusually among sharks, they also possess a luminous organ.
Gummy shark
Gummy sharks are found to be mostly bottom dwellers in the waters around southern Australia, from Shark Bay in Western Australia to Port Stephens in New South Wales, from the surface down to a depth of 350 metres in moderate-temperature water. The reproduction of the single-sex school gummy sharks is ovoviviparous. Ovoviviparous organisms are those who produce young via egg and hatched inside of the parents' bodies. A common example of an ovoviviparous being is a seahorse. Females can have up to 57 pups per litter and are ready to do so by the age of five. The average number of pups per litter birthed by the female Mustelus antarcticus is 14 but can have up to 57. Male sharks are ready to reproduce by the age of four. Gestation takes approximately one year. The typical generation length for the gummy shark is 10 years and have an average life expectancy of 16 years. These sharks pose no known threat to beach goers or fisherman. This species is also of least concern in terms of endangerment according to the IUCN Red List is an extensive list of species and where they fall on the endangered scale from “Least concern” (LC) to “Extinct” (EX).
Caribbean roughshark
"Oxynotus caribbaeus" is a small shark found in the upper continental slope of Venezuela; it is easily distinguishable from other "Oxynotus" species. Adult males reach a maximum size of in length and the females are thought to grow even longer, although none has been examined. The Caribbean roughshark has a short, blunt snout and head. This chubby-looking shark looks nothing like the typical shark. It has two dorsal fins that help differentiate this shark from other "Oxynotus" species. Its first dorsal fin is inclined forward, is very long and thick, and triangular in shape. The second dorsal fin is similar to the first, although it is not as long. However, as some other "Oxynotus" species, the Caribbean roughshark does not have an anal fin. It has the typical shark coarse dermal denticles, but these are atypically large for the size of the shark. It contains small, circular spiracles at the dorsal base of its head. The supraorbital ridges are not expanded and do not form a knob in front of the spiracles. It has lanceolate upper teeth, containing 12 rows and lower bladelike teeth containing 12 rows.
Coral reef fish
Grey reef sharks are usually less than 1.9 metres (6.2 ft) long. Despite their moderate size, grey reef sharks actively expel most other shark species from favored habitats. In areas where this species co-exists with the blacktip reef shark, the latter species occupy the shallow flats while the grey reef sharks stay in deeper water. Many grey reef sharks have a home range on a specific area of the reef, to which they continually return. However, they are social rather than territorial. During the day, these sharks often form groups of 5–20 individuals near coral reef drop-offs, splitting up in the evening as the sharks begin to hunt. They are found over continental and insular shelves, preferring the leeward (away from the direction of the current) sides of coral reefs with clear water and rugged topography. They are frequently found near the drop-offs at the outer edges of the reef, and less commonly within lagoons. On occasion, this shark may venture several kilometers out into the open ocean.
Dusky moorhen
The dusky moorhen is a medium size bird, slightly smaller than the purple swamphen. The New Guinea birds are smaller, at in length, than the Australian race . Adult males generally weigh on average around 570 grams and adult females 493 grams. The adult dusky moorhen is mainly dark grey-black, with a browner tinge to the upper parts. It has a red frontal shield and yellow-tipped red bill like its Eurasian relative, but lacks the white flank line shown by common moorhen, and has orange-yellow rather than yellow legs. The Australian subspecies is larger and pager than both other subspecies.
Ouachita dusky salamander
The Ouachita dusky salamander grows to about in length including a finned tail. The upper side is greenish-brown or grey of a fairly uniform colour and the juveniles have a row of pale spots along each side. There are fourteen costal rib grooves on either side.
Spot-tail shark
The spot-tail shark is a spindle-shaped fish growing to about . It has a fairly long, pointed snout and moderately large eyes. The first dorsal fin is large and curved while the second dorsal fin is small and low. The back and sides are grey and the belly white, and there is a long white streak on the flank. This species can be distinguished from other requiem sharks found in tropical waters by the distinctive black tips to the second dorsal fin, the pectoral fins and the lower lobe of the caudal fin. There is a ridge over the spine extending from the first to the second dorsal fin and a pit just in front of the upper lobe of the caudal fin. The upper teeth are serrated, oblique and triangular. The Australian blacktip shark ("Carcharhinus tilstoni"), which occupies a similar range, has similar black tips to the fins but additionally has a black tip to its first dorsal fin. It lacks the ridge between the two dorsal fins and its upper teeth are also different, being slender, upright and pointed.
Whitecheek shark
The whitecheek shark grows to a length of about . It has a slender body and long head with a rounded snout. The eyes are oval and both jaws have multiple rows of backward-pointing, serrated teeth. The pectoral fins are long, narrow, and curved and have narrow, pointed tips. The first dorsal fin is triangular, uncurved, and moderate-sized, and the second dorsal fin is much smaller than the first and bears a large black patch at its apex. The whitecheek shark's dorsal (upper) surface is grey or brownish-grey while its ventral (under) surface is pale.
Dusky shark
In the northwestern Atlantic, around 60% of the dusky shark's diet consists of bony fishes, from over ten families with bluefish ("Pomatomus saltatrix") and summer flounder ("Paralichthys dentatus") being especially important. Cartilaginous fishes, mainly skates and their egg cases, are the second-most important dietary component, while the lady crab ("Ovalipes ocellatus") is also a relatively significant food source. In South African and Australian waters, bony fishes are again the most important prey type. Newborn and juvenile sharks subsist mainly on small pelagic prey such as sardines and squid; older sharks over long broaden their diets to include larger bony and cartilaginous fishes. The run of the southern African pilchard ("Sardinops sagax"), occurring off the eastern coast of South Africa every winter, is attended by medium and large-sized dusky sharks. Pregnant and post-partum females do not join, possibly because the energy cost of gestation leaves them unable to pursue such swift prey. One South African study reported that 0.2% of the sharks examined had preyed upon bottlenose dolphins ("Tursiops truncatus").
Stegastes fuscus
The colour of an adult dusky damselfish varies from brownish-olive to dark grey, with fine, darker-coloured, vertical stripes on the body. The fins are large with sometimes a blue rim around the edge of the dorsal and anal fins. The dorsal fin has 12 spines and 15-16 soft rays while the anal fin has two spines and 13-14 soft rays. The dusky damselfish can be distinguished from the very similar longfin damselfish ("Stegastes diencaeus") by the shorter, less angular dorsal and anal fins. The maximum length is , but is a more typical length.
Thresher shark
Named for their exceptionally long, thresher-like heterocercal tail or "caudal fins" (which can be as long as the total body length), thresher sharks are active predators; the tail is used as a weapon to stun prey. The thresher shark has a short head and a cone-shaped nose. The mouth is generally small, and the teeth range in size from small to large. By far the largest of the three species is the common thresher, "Alopias vulpinus", which may reach a length of and a weight of over . The bigeye thresher, "Alopias superciliosus", is next in size, reaching a length of 4.9 m (16 ft); at just 3 m (10 ft), the pelagic thresher, "Alopias pelagicus", is the smallest.
Porbeagle
The dorsal coloration is a medium to dark gray or slate, extending to the bases of the pectoral fins. The underside is white; adults in the Southern Hemisphere often have dark coloring under the head and dusky blotches scattered over the belly. The free rear tip of the first dorsal fin is abruptly light gray or white, a feature unique to this species. The porbeagle may attain a length of , though this is uncertain and may have resulted from confusion with other mackerel shark species. A more typical length is . Female sharks grow larger than males in the North Atlantic, with maximum confirmed fork lengths (snout tip to caudal fin fork) of for males and for females. Southern Hemisphere sharks are smaller and the two sexes are similar in size, with males and females attaining fork lengths of and respectively. Most porbeagles weigh no more than , with the record being a individual caught off Caithness, Scotland, in 1993.
Dark shyshark
When threatened, the dark shyshark curls into a ring with its tail covering its eyes, hence the name "shyshark". It preys mainly on small crustaceans, bony fishes, and molluscs. Reproduction is oviparous and proceeds throughout the year. Females lay two egg cases at a time, which hatch after 6–10 months. This harmless species is of little commercial significance due to its small size. It is frequently caught by recreational fishers and persecuted as a pest. The International Union for Conservation of Nature (IUCN) has listed the dark shyshark under Least Concern, as it is common and does not appear to be substantially threatened by fishing or habitat degradation.
Yellowspotted catshark
The yellowspotted catshark feeds on small fish, crustaceans and squid. It is an egg-laying species, laying a single egg at a time, and enclosing it in an egg case roughly . The juvenile fish when they hatch may measure about and the adults can grow to but most individuals are under a metre (3 ft) long. This shark is more common on rocky reefs than on sandy seabeds.
Platycephalus fuscus
Dusky flathead are the largest of the many species of flathead found in Australia, and the most commonly caught. Dusky flathead have very rarely been caught at sizes up to 12–15 kg and lengths up to 1.5 metres, but average size is 0.5–1.5 kg and 40–50 cm. Typically a fish of estuaries and estuarine lakes, dusky flathead are rarely found in other habitats.
Great white shark
One contender in maximum size among the predatory sharks is the tiger shark ("Galeocerdo cuvier"). While tiger sharks which are typically both a few feet smaller and have a leaner, less heavy body structure than white sharks, have been confirmed to reach at least in the length, an unverified specimen was reported to have measured in length and weighed , more than two times heavier than the largest confirmed specimen at . Some other macropredatory sharks such as the Greenland shark ("Somniosus microcephalus") and the Pacific sleeper shark ("S. pacificus") are also reported to rival these sharks in length (but probably weigh a bit less since they are more slender in build than a great white) in exceptional cases. The question of maximum weight is complicated by the unresolved question of whether or not to include the shark's stomach contents when weighing the shark. With a single bite a great white can take in up to of flesh, and can also consume several hundred kilograms of food.
David's angelshark
David's angelshark "(Squatina david)" is a species of angelshark newly described in 2016. It can grow up to around 75cm in length and is coloured greyish to brownish yellow. Male specimen are dark-spotted, while females have abundant whitish spots. David's angelshark inhabits the northern coast of South America from Colombia to Suriname and is currently known from a depth between 100-150m.
Oceanic whitetip shark
"C. longimanus" has a 'typical', although somewhat flattened requiem shark body, often with a mildly humpbacked aspect. It is bronze, brown, bluish, or grey dorsally (the colour varies by region), and white ventrally (although it may occasionally have a yellow tint). The oceanic whitetip shark is a medium-sized requiem shark. The largest specimen ever caught measured , an exceptionally large size considering few specimens are known to exceed a length of . The maximum reported weight is . The female is typically larger than the male by . Males attain sexual maturity at and females about . In the Gulf of Mexico in the 1950s, the mean weight of oceanic whitetip sharks was . In the 1990s, the sharks of the species from the same area averaged only .
Tiger shark
The tiger shark commonly attains a length of and weighs around . It is dimorphic, with exceptionally large females reportedly measuring over , and the largest males . Weights of particularly large female tiger sharks can exceed . One pregnant female caught off Australia reportedly measured long and weighed . Even larger unconfirmed catches have been claimed. Some papers have accepted a record of an exceptional length for a tiger shark, but since this is far larger than any scientifically observed specimen, verification would be needed.
Shark
Under this broader definition, the earliest known sharks date back to more than 420 million years ago. Acanthodians are often referred to as "spiny sharks"; though they are not part of Chondrichthyes proper, they are a paraphyletic assemblage leading to cartilaginous fish as a whole. Since then, sharks have diversified into over 500 species. They range in size from the small dwarf lanternshark ("Etmopterus perryi"), a deep sea species of only in length, to the whale shark ("Rhincodon typus"), the largest fish in the world, which reaches approximately in length. Sharks are found in all seas and are common to depths of . They generally do not live in freshwater although there are a few known exceptions, such as the bull shark and the river shark, which can survive and be found in both seawater and freshwater. Sharks have a covering of dermal denticles that protects their skin from damage and parasites in addition to improving their fluid dynamics. They have numerous sets of replaceable teeth.
Night shark
The night shark is a deepwater species that has been reported from as far down as , though it occasionally ventures to within of the surface. Off the southeastern United States, it is usually caught at a depth range of . Off northeastern Brazil, the night shark is most commonly found near the summits of seamounts ranging from to deep. Off West Africa, it occurs at depths of , where the temperature is 11–16 °C (52–61 °F), the salinity is 36 ppt, and the dissolved oxygen level is 1.81 ml/l. Annual variation in Cuban catch rates may indicate a seasonal migration.
Blacknose shark
The first dorsal fin is small and somewhat sickle-shaped, with a pointed apex and a short, free, rear tip; its origin lies over the free rear tips of the pectoral fins. The second dorsal fin is relatively large, though still less than half the height of the first. No ridge is seen between the dorsal fins. The pectoral fins are short and tapered. The body is covered with overlapping dermal denticles that bear five to seven longitudinal ridges (three in very young individuals) leading to three to five marginal teeth. The coloration is yellowish to greenish-gray or brown above and white to yellow below. A distinctive dark blotch at the tip of the snout is most obvious in young sharks. The tips of the second dorsal fin, upper caudal fin lobe, and sometimes the lower caudal fin lobe, are dark. Blacknose sharks are typically long and in weight. The maximum length and weight on record is and , respectively.
A small, fast-swimming predator, the blacknose shark feeds primarily on small, bony fishes, including pinfish, croakers, porgies, anchovies, spiny boxfish, and porcupinefish, as well as on octopus and other cephalopods. When competing for bait, their speed allows them to snatch food from larger sharks such as the Caribbean reef shark ("C. perezi"). This species may form large schools that are sometimes associated with anchovies and mullet. Blacknose sharks demonstrate a high degree of philopatry: both juveniles and adults have been documented returning to the same local area year after year.
Silky shark
The skin is densely covered by minute, overlapping dermal denticles. Each dermal denticle is diamond-shaped and bears horizontal ridges leading to posterior marginal teeth, which increase in number as the shark grows. The back is metallic golden-brown to dark gray and the belly is snowy white, which extends onto the flank as a faint lighter stripe. The fins (except for the first dorsal) darken at the tips; this is more obvious in young sharks. The coloration quickly fades to a dull gray after death. One of the larger members of its genus, the silky shark commonly reaches a length of , with a maximum recorded length and weight of and , respectively. Females grow larger than males.
Whitecheek shark
The whitecheek shark or widemouth blackspot shark ("Carcharhinus dussumieri"), is a requiem shark of the family Carcharhinidae, found in the Indo-West Pacific Ocean between latitudes 34°N and 25°S. It can reach a length of 1 m. It feeds mainly on fish, cephalopods, and crustaceans. It is a viviparous species, with the female giving birth to up to four live young.
Dusky shark
Newborn dusky sharks measure long; pup size increases with female size, and decreases with litter size. There is evidence that females can determine the size at which their pups are born, so as to improve their chances of survival across better or worse environmental conditions. Females also provision their young with energy reserves, stored in a liver that comprises one-fifth of the pup's weight, which sustains the newborn until it learns to hunt for itself. The dusky shark is one of the slowest-growing shark species, reaching sexual maturity only at a substantial size and age (see table). Various studies have found growth rates to be largely similar across geographical regions and between sexes. The annual growth rate is over the first five years of life. The maximum lifespan is believed to be 40–50 years or more.
Great white shark
In great white sharks, sexual dimorphism is present, and females are generally larger than males. Male great whites on average measure long, while females at . Adults of this species weigh on average, however mature females can have an average mass of . The largest females have been verified up to in length and an estimated in weight, perhaps up to . The maximum size is subject to debate because some reports are rough estimations or speculations performed under questionable circumstances. Among living cartilaginous fish, only the whale shark ("Rhincodon typus"), the basking shark ("Cetorhinus maximus") and the giant manta ray ("Manta birostris"), in that order, are on average larger and heavier. These three species are generally quite docile in disposition and given to passively filter-feeding on very small organisms. This makes the great white shark the largest extant macropredatory fish. Great white sharks are at around when born, and grow about each year.
Frilled shark
The frilled shark ("Chlamydoselachus anguineus") 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 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 has been caught as deep as , although it is uncommon below . In Suruga Bay, Japan, it is most common at depths of . Exhibiting several primitive features, the frilled shark has often been termed a living fossil. It reaches a length of 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 its six pairs of gill slits, with the first pair meeting across the throat.
Dusky catshark
The dusky catshark ("Bythaelurus canescens") is a catshark of the family Scyliorhinidae, found from Peru and Chile to the Straits of Magellan.
Sand tiger shark
Adult sand tigers range from to in length and to in weight. The head is pointy, as opposed to round, while the snout is flattened with a conical shape. Its body is stout and bulky and its mouth extends beyond the eyes. The eyes of the sand tiger shark are small, lacking eyelids. A sand tiger usually swims with its mouth open displaying three rows of protruding, smooth-edged, sharp-pointed teeth. The males have grey claspers with white tips located on the underside of their body. The caudal fin is elongated with a long upper lobe (i.e. strongly heterocercal). They have two large, broad-based grey dorsal fins set back beyond the pectoral fins. The sand tiger shark has a grey-brown back and pale underside. Adults tend to have reddish-brown spots scattered, mostly on the hind part of the body. In August 2007, an albino specimen was photographed off South West Rocks, Australia. The teeth of these sharks have no transverse serrations (as have many other sharks) but they have a large, smooth main cusp with a tiny cusplet on each side of the main cusp. The upper front teeth are separated from the teeth on the side of the mouth by small intermediate teeth.
Blacktip shark
The coloration is gray to brown above and white below, with a conspicuous white stripe running along the sides. The pectoral fins, second dorsal fin, and the lower lobe of the caudal fin usually have black tips. The pelvic fins and rarely the anal fin may also be black-tipped. The first dorsal fin and the upper lobe of the caudal fin typically have black edges. Some larger individuals have unmarked or nearly unmarked fins. Blacktip sharks can temporarily lose almost all their colors during blooms, or "whitings", of coccolithophores. This species attains a maximum known length of , though is more typical, and a maximum known weight of .
Blackspotted catshark
The blackspotted catshark ("Halaelurus buergeri") is a catshark of the family Scyliorhinidae. It is found in the waters off the coasts of Japan, Korea, China, and Taiwan between latitudes 39° N and 20° N, at the depths of between 80 and 100 m. It can grow up to 49 cm in length.
Bramble shark
The bramble shark ("Echinorhinus brucus") is one of the two species of sharks in the family Echinorhinidae. Aside from the eastern Pacific Ocean, it is found in tropical and temperate waters worldwide. This rarely encountered shark swims close to the bottom of the seafloor, typically at depths of , though it may enter much shallower water. The bramble shark has a stout body with two small dorsal fins positioned far back and no anal fin. It can be readily identified by the large, thorn-like dermal denticles scattered over its body, some of which may be fused together. It is purplish brown or black in color and grows up to long.
Rainbow shark
An adult rainbow shark thrives in a minimum of 30 gallons of water, with an aquarium length of 48 inches, at the neutral pH range (6.0 to 8.0 pH), with temperatures between , and water hardness maintained at 5 to 11 dH. They must have this much space, as they frequently swim around quickly and will terrorize other fish in any tank under this size.
Horn shark
The body is cylindrical, with two high, somewhat falcate (sickle-shaped) dorsal fins bearing stout spines at the front. The fin spines of reef-dwelling horn sharks are shorter than those living in algal habitats, as their spines become worn down on rocks from the sharks' movements. The first dorsal fin originates over the bases of the large pectoral fins, while the second dorsal fin originates slightly anterior to the free rear tips of the pelvic fins. The caudal fin has a short lower lobe and a long, broad upper lobe with a strong notch near the tip. The horn shark's dermal denticles are small and smooth, numbering some 200/cm on the back in adults. The dorsal coloration consists of various shades of gray or brown with many small dark spots, though these may be absent in older sharks; the underside is yellowish. There is a dark patch of small spots below the eye. This species may reach a length of , though most individuals do not exceed .
Greenland shark
The Greenland shark is one of the largest living species of shark, with dimensions comparable to those of the great white shark. Greenland sharks grow to and , and possibly up to and more than . Most Greenland sharks observed have been around long and weigh up to .
Spinner shark
The average spinner shark is long and weighs ; this species attains a maximum known length and weight of and . Indo-Pacific sharks are generally larger than those from the northwest Atlantic. This species has a slim, streamlined body with a distinctive, long, pointed snout. The eyes are small and circular. Prominent forward-pointing furrows occur at the corners of the mouth. The tooth rows number 15–18 in each half of the upper jaw and 14–17 in each half of the lower jaw, with two and one tiny symphysial (central) teeth, respectively. The teeth have long, narrow central cusps and are finely serrated in the upper jaw and smooth in the lower jaw. The five pairs of gill slits are long.
Blackspot shark
The blackspot shark is a relatively slender species with a streamlined appearance, growing to a length around . The snout is fairly long, pointed or slightly rounded at the tip. The eyes are large, oval, and set horizontally, and are protected by a nictitating membrane on the lower side. The flaps of skin beside the nostrils are triangular, and the furrows on the upper lip are short. Usually, 12 tooth rows occur on either side of both top and bottom jaws, but the number can vary from 11 to 13. The upper teeth have strongly serrated oblique cusps and smooth-edged cusplets, and the lower teeth have oblique cusps, either serrated or smooth. The hindermost of the five gill slits is above the origin of the pectoral fins, and no spiracles occur. The first dorsal fin is long, narrow, and curved (falcate) and has a short rear tip. It is either pointed or narrowly rounded at the apex and its origin is directly over the free posterior end of the pectoral fins. The second dorsal fin is relatively large. It also has a short rear tip and its origin is slightly behind the origin of the anal fin. The pectoral fins are falcate, long and narrow, and taper to a blunt point. No fleshy keel exists along the sides of the caudal peduncle. The caudal fin is about one-fifth of the total length of the shark, the dorsal lobe is elongated and has a notch in the lower margin near the tip and the ventral lobe is smaller, markedly falcate, and has a more rounded tip. The body colour is brownish or silvery grey on the dorsal surface and pale grey on the ventral surface, with an inconspicuous pale stripe running along the flank. A large, triangular black spot is on the second dorsal fin which covers at least half of the fin. The other fins have no distinctive markings, but do have pale posterior edges.
Prickly shark
The lateral line runs along each side of body in a conspicuous furrow. The pectoral fins are short, while the pelvic fins are relatively large with long bases. The first dorsal fin is small and originates at or behind the level of the pelvic fin origins; the second dorsal fin is similar to the first and positioned close behind. The anal fin is absent, and the stout caudal peduncle lacks depressions at the caudal fin origins. The caudal fin has a longer upper lobe without a notch in the trailing margin, and an indistinct lower lobe. The skin has a dense, uniform covering of non-overlapping dermal denticles measuring up to across, which are never fused together as in the bramble shark. Each denticle is thorn-like, with strong ridges running down the central spine and radiating out over the star-shaped base. The denticles beneath the snout are very fine in adults. The prickly shark is plain brown or gray, often with a purplish tint, and has black trailing margins on the fins. The underside is paler, most obviously on the snout and around the mouth. It may reach a length of . The maximum recorded weight is for a long female.
Great dusky swift
The great dusky swift ("Cypseloides senex") is a South American species of swift in the family Apodidae. At 18 cm in length, it is large relative to other swifts, and dark brown in colour with a pale coloured head.
Crocodile shark
The pectoral fins are small, broad, and rounded. The pelvic fins are nearly as large as the pectorals. The first dorsal fin is small, low and angular; the second dorsal fin is smaller than the first but larger than the anal fin. The caudal fin is asymmetrical with a moderately long upper lobe. The caudal peduncle is slightly compressed with weak lateral keels. The dermal denticles are small, with a flattened crown bearing small ridges and backward-pointing cusps It is dark brown above and paler below, sometimes with a few dark blotches on the sides and belly and/or a white blotch between the corner of the mouth and the first gill slit. The fins have thin translucent to white margins. The crocodile shark grows to a maximum length of 1.1 m (3.6 ft). Most individuals are 1 m (3 ft) long and weigh 4–6 kg (9–13 lbs).
Shortfin mako shark
The shortfin mako shark is a fairly large species of shark. Growth rates appear to be somewhat accelerated in comparison to other species in the lamnid family. An average adult specimen measures around in length and weighs from . The species is sexually dimorphic, with females typically larger than males. Large specimens are known, with a few large, mature females exceeding a length of and a weight of . The largest taken on hook-and-line was , caught off the coast of California on June 3, 2013, and the longest verified length was caught off of the coast of France in September 1973. A specimen caught off the coast of Italy and examined in an Italian fish market in 1881 was reported to weigh an extraordinary at a length of . Yet another fish was caught off Marmaris, Turkey in the late 1950's at an estimated size of between 5.77 m (18.9 ft) and 6.19 m (20.3 ft) making it the largest known specimen of the species. However, this estimate was created using photos of the shark and not at the time of capture so this estimate must be taken with reasonable caution. The authors did not estimate a weight for this specimen.
Dusky sole
The dusky sole, "Lepidopsetta mochigarei", is a flatfish of the family Pleuronectidae. It is a demersal fish that lives on bottoms in the temperate waters of the northwest Pacific, from the Korean peninsula to the southern Sea of Okhotsk. It grows up to in length.
Caribbean reef shark
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 long; the maximum recorded length is and the maximum reported weight is . 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.
Dusky megapode
The dusky megapode or dusky scrubfowl ("Megapodius freycinet") is a medium-sized (about 41 cm long), blackish bird with a short pointed crest, bare red facial skin, dark legs, brown irises, and dark brown and yellow bill. The male and female are similar. This terrestrial species lives in forests and swamps, including mangroves, of the Maluku and Raja Ampat Islands in Indonesia. Like other megapodes, it lays its eggs in a mound made from earth mixed with leaves, sand, gravel, and sticks, as big as in diameter and stand nearly tall.
Dusky dolphin
The dusky dolphin ("Lagenorhynchus obscurus") is a dolphin found in coastal waters in the Southern Hemisphere. Its specific epithet is Latin for "dark" or "dim". It is very closely genetically related to the Pacific white-sided dolphin, but current scientific consensus holds they are distinct species. The dolphin's range is patchy, with major populations around South America, southwestern Africa, New Zealand, and various oceanic islands, with some sightings around southern Australia and Tasmania. The dusky dolphin prefers cool currents and inshore waters, but can also be found offshore. It feeds on a variety of fish and squid species and has flexible hunting tactics. The dusky dolphin is known for its remarkable acrobatics, having a number of aerial behaviours. The status of the dolphin is unknown, but it has been commonly caught in gill nets.
Dumb gulper shark
The dumb gulper shark may grow to be long and has a long, robust head, a long, flattened snout, a large mouth, and large, green eyes, which help it see at 820 to 1260 ft (250 to 385 m) under water. The body is slender and of moderate size, and is grey to greyish-brown in colour, with a paler underside. Of the two dorsal fins, the first is larger than the second, and each has a short spine, a white rear margin, and a dark blotch towards the front, which is more distinct in juveniles. The large caudal fin is asymmetrical, with a longer upper than lower lobe.
Squalicorax
These sharks are of medium size, up to 5 m (usually around 2 m) in length. Their bodies were similar to the modern gray sharks, but the shape of the teeth is strikingly similar to that of a tiger shark. The teeth are numerous, relatively small, with a curved crown and serrated, up to 2.5 – 3 cm in height (the only representative of the Mesozoic Lamniformes with serrated teeth). Large numbers of fossil teeth have been found in Europe, North Africa, and North America.
Dusky shark
In addition to commercial shark fisheries, dusky sharks are also caught as bycatch on longlines meant for tuna and swordfish (and usually kept for its valuable fins), and by recreational fishers. Large numbers of dusky sharks, mostly juveniles, are caught by sport fishers off South Africa and eastern Australia. This shark was once one of the most important species in the Florida trophy shark tournaments, before the population collapsed.
Eleotris fusca
The dusky sleeper or brown spinecheek gudgeon ("Eleotris fusca") is a species of fish in the family Eleotridae found in many Indo-West Pacific regions, from the coast of eastern Africa to Hawaii, where it can be found in lagoons, estuaries, and freshwater streams with muddy bottoms. This species can reach a length of .
Slender catshark
The slender catshark is a small, elongated shark that grows to a length of about . The snout is relatively broad and rounded, the mouth is wide and the nostrils are concealed by lobed flaps. The second dorsal fin is larger than the first and the upper lobe of the tail fin is much larger than the lower lobe. The general colour of the dorsal (upper) surface is pale brown and there are seven or eight dark brown saddle-shaped patches with a scattering of dark brown spots between them.
Goblin shark
The goblin shark ("Mitsukurina owstoni") is a rare species of deep-sea shark. Sometimes called a "living fossil", it is the only extant representative of the family Mitsukurinidae, a lineage some 125 million years old. This pink-skinned animal has a distinctive profile with an elongated, flattened snout, and highly protrusible jaws containing prominent nail-like teeth. It is usually between long when mature, though it can grow considerably larger. Goblin sharks inhabit upper continental slopes, submarine canyons, and seamounts throughout the world at depths greater than , with adults found deeper than juveniles.
Whale shark
The whale shark is the largest non-cetacean animal in the world. The average size of adult whale sharks is estimated at and . Several specimens over in length have been reported. The largest verified specimen was caught on 11 November 1949, near Baba Island, in Karachi, Pakistan. It was long, weighed about , and had a girth of . Stories exist of vastly larger specimens – quoted lengths of and are common in the popular literature, but no scientific records support their existence. In 1868, the Irish natural scientist Edward Perceval Wright obtained several small whale shark specimens in the Seychelles, but claimed to have observed specimens in excess of , and tells of shark specimens surpassing .
Iridescent shark
Iridescent sharks require a minimum tank size of to develop naturally. Schools require even larger tanks. If given enough room and fed adequately, they can reach in length. In most home aquaria, the lack of space stunts their growth. For this reason, most iridescent sharks kept in home aquaria grow to in length only and may die prematurely. When provided adequately sized aquaria and proper husbandry, iridescent sharks may live into their teens and grow to full size.
Brownbanded bamboo shark
The minimum size of the tank that can carry an adult cat shark is about 180 gallons. Because these sharks are nocturnal species they will need some type of shaded area within the tank where the shark could hide. Although these sharks do not swim around too much, it is highly suggested that the items within the tank should be stable; cat sharks are very strong and will knock down anything that is not stable inside the tank. Also this shark should not be placed with Triggers and Puffers, they will nip at the shark’s fins, nor should they be placed with aggressive feeders.
Dusky lory
The dusky lory is short-tailed parrot about 25 cm (10 in) long. It is mainly brown and has a whitish back and rump. It has two colour phases; the band across the upper chest together with its abdomen are either yellow or orange. The beak is dark orange and there is an area of bare orange skin at the base of its lower mandible. The irises are red and the legs are grey. The male and females are identical in external appearance. Juveniles are duller with a yellowish back and rump, yellowish-grey irises, and a beak that is yellow at the base and brown/black towards the tip.
Blind shark
Maturing at under long, the blind shark has a stocky, grayish to brownish body with white flecks and darker bands that fade with age. Its head is wide, flattened, and blunt, with small eyes on top and a pair of long barbels underneath. It has large pectoral fins, two nearly equal-sized dorsal fins placed far back on the body, and an anal fin placed close to the caudal fin. The blind shark feeds primarily on small invertebrates and bony fishes. It is aplacental viviparous with females bearing litters of 7–8 pups in the summer. This small shark adapts readily to being kept in captivity. It is not valued by either commercial or recreational fishers, and its hardiness means that incidentally caught individuals are likely to be returned to the water alive. In the absence of substantial threats to its population, the International Union for Conservation of Nature has assessed it as of Least Concern.
Leopard catshark
The background color of the leopard catshark ranges from off-white to glossy jet black above and white to almost black below, sometimes with an abrupt transition between the two. Overlaid is a striking pattern of black markings variously combining small to large spots, blotches, complete to incomplete rosettes, and/or short to long lines, that may extend almost to the midline of the belly. There are four named forms: 'typical', with leopard-like rosettes and broken lines, 'marleyi', with large round spots, 'salt and pepper', with densely packed dots, and 'melanistic', with an almost completely black upper surface and irregular stripes and/or spots; many sharks are intermediate between these forms. Color pattern is affected by development: all hatchling sharks have large black spots, that with age tend to break up into rosettes and smaller spots, that may eventually merge into lines. The 'marleyi' form appears to be a type of paedomorphosis, in which in the hatchling pattern is carried into adulthood. Color pattern is also related to geographic location, with the 'marleyi' and 'salt and pepper' forms apparently restricted to the waters off the Eastern Cape and KwaZulu-Natal. The leopard catshark reaches a maximum known length of and a maximum known weight of ; males grow slightly larger than females.
Rough longnose dogfish
Maximum length is 109 cm. Found in the Eastern Atlantic around Madeira and in the western Pacific around southern Japan, this shark is rarely seen, but lives between 600 and 1,000 m. It is ovoviviparous with probably around 12 pups per litter.
Nervous shark
The pectoral fins are moderately long, narrow, and pointed. The first dorsal fin originates over the free rear tips of the pectoral fins; it is large and falcate (sickle-shaped) with a pointed apex. The second dorsal fin is positioned opposite the anal fin and is relatively large and high. There is no ridge between the dorsal fins. A crescent-shaped notch is present on the caudal peduncle just before the upper caudal fin origin. The caudal fin is asymmetrical, with a strong lower lobe and a longer upper lobe with a ventral notch near the tip. The dermal denticles are overlapping and bear three horizontal ridges (five in larger individuals) leading to marginal teeth. This species is bronze to gray above and white below, with a white stripe on the flank. A thin black line runs along the leading margins of the dorsal fins, pectoral fins, and the upper caudal fin lobe, as well as the caudal fin trailing margin; the lower caudal fin lobe and sometimes the pectoral fins are also tipped in black. The nervous shark typically reaches in length and may grow up to long. Females attain larger sizes than males.
Dusky shark
Teeth belonging to the dusky shark are fairly well represented in the fossil record, though assigning "Carcharhinus" teeth to species can be problematic. Dusky shark teeth dating to the Miocene (23-5.3 Ma) have been recovered from the Kendeace and Grand Bay formations in Carriacou, the Grenadines, the Moghra Formation in Egypt, Polk County, Florida, and possibly Cerro La Cruz in northern Venezuela. Teeth dating to the Late Miocene or Early Pliocene (11.6-3.6 Ma) are abundant in the Yorktown Formation and the Pungo River, North Carolina, and from the Chesapeake Bay region; these teeth differ slightly from the modern dusky shark, and have often been misidentified as belonging to the oceanic whitetip shark ("C. longimanus"). Dusky shark teeth have also been recovered from the vicinity of two baleen whales in North Carolina, one preserved in Goose Creek Limestone dating to the Late Pliocene ("c." 3.5 Ma), and the other in mud dating to the Pleistocene-Holocene ("c." 12,000 years ago).
Bull shark
Bull sharks are large and stout, with females being larger than males. The bull shark can be up to in length at birth. Adult female bull sharks average long and typically weigh , whereas the slightly smaller adult male averages and . While a maximum size of is commonly reported, a single record exists of a female specimen of exactly . The maximum recorded weight of a bull shark was , but may be larger. Bull sharks are wider and heavier than other requiem sharks of comparable length, and are grey on top and white below. The second dorsal fin is smaller than the first. The bull shark's caudal fin is longer and lower than that of the larger sharks, and it has a small snout, and lacks an interdorsal ridge.
Dusky shark
The range of the dusky shark extends worldwide, albeit discontinuously, in tropical and warm-temperate waters. In the western Atlantic Ocean, it is found from Massachusetts and the Georges Bank to southern Brazil, including the Bahamas and Cuba. In the eastern Atlantic Ocean, it has been reported from the western and central Mediterranean Sea, the Canary Islands, Cape Verde, Senegal, Sierra Leone, and possibly elsewhere including Portugal, Spain, Morocco, and Madeira. In the Indian Ocean, it is found off South Africa, Mozambique, and Madagascar, with sporadic records in the Arabian Sea, the Bay of Bengal, and perhaps the Red Sea. In the Pacific Ocean, it occurs off Japan, mainland China and Taiwan, Vietnam, Australia, and New Caledonia in the west, and from southern California to the Gulf of California, around Revillagigedo, and possibly off northern Chile in the east. Records of dusky sharks from the northeastern and eastern central Atlantic, and around tropical islands, may in fact be of Galapagos sharks. Mitochondrial DNA and microsatellite evidence suggest that Indonesian and Australian sharks represent distinct populations.
Bluntnose sixgill shark
The bluntnose sixgill shark ("Hexanchus griseus"), often simply called the cow shark, is the largest hexanchoid shark, growing to in length. It is found in tropical and temperate waters worldwide and its diet is widely varied by region.
Smalltooth sand tiger
No pregnant smalltooth sand tigers have ever been found; this species is presumed to be ovoviviparous as in other mackerel sharks. Villaviencio-Garayzar (1996) described a 3.6 m (11.8 ft) female from the Gulf of California that contained "hundreds of ova" in her right ovary, which would support the embryos being oophagous. Whether the embryos also cannibalize each other as in the grey nurse shark is unknown. The size at birth is estimated to be 1.0–1.1 m (3.3–3.6 ft). With a few recorded exceptions, juveniles are found in deep water and only adults are present above a depth of 200 m (660 ft); this may serve to reduce predation on young individuals by large, shallow-water predators such as the great white shark ("Carcharodon carcharias"). Males mature at a length of 2.0–2.5 m (6.6–8.2 ft) and females at a length of 3.0–3.5 m (9.4–11.5 ft). Faint scars seen on some individuals may be related to courtship.
Dusky shark
Residing off continental coastlines from the surf zone to the outer continental shelf and adjacent oceanic waters, the dusky shark occupies an intermediate habitat that overlaps with its more specialized relatives, such as the inshore sandbar shark, the pelagic silky shark ("C. falciformis") and oceanic whitetip shark, the deepwater bignose shark, and the islandic Galapagos shark and silvertip shark ("C. albimarginatus"). One tracking study in the northern Gulf of Mexico found that it spends most of its time at depths of , while making occasional forays below ; this species has been known to dive as deep as . It prefers water temperatures of , and avoids areas of low salinity such as estuaries.
Great white shark
White sharks also attack dolphins and porpoises from above, behind or below to avoid being detected by their echolocation. Targeted species include dusky dolphins ("Lagenorhynchus obscurus"), Risso's dolphins ("Grampus griseus"), bottlenose dolphins ("Tursiops" ssp.), Humpback dolphins ("Sousa" ssp.), harbour porpoises ("Phocoena phocoena"), and Dall's porpoises ("Phocoenoides dalli"). Groups of dolphins have occasionally been observed defending themselves from sharks with mobbing behaviour. White shark predation on other species of small cetacean has also been observed. In August 1989, a juvenile male pygmy sperm whale ("Kogia breviceps") was found stranded in central California with a bite mark on its caudal peduncle from a great white shark. In addition, white sharks attack and prey upon beaked whales. Cases where an adult Stejneger's beaked whale ("Mesoplodon stejnegeri"), with a mean mass of around , and a juvenile Cuvier's beaked whale ("Ziphius cavirostris"), an individual estimated at , were hunted and killed by great white sharks have also been observed. When hunting sea turtles, they appear to simply bite through the carapace around a flipper, immobilizing the turtle. The heaviest species of bony fish, the oceanic sunfish ("Mola mola"), has been found in great white shark stomachs.
Angelshark
While the forward part of the angel shark's body is broad and flattened, the rear part retains a muscular appearance more typical of other sharks. The eyes and spiracles are on top and the five gill slits are on its back. Both the pectorals and the pelvic fins are large and held horizontally. There are two dorsal fins, no anal fin and unusually for sharks, the lower lobe of the caudal fin is longer than the upper lobe. Most types grow to a length of 1.5 m (5 ft), with the Japanese angel shark, known to reach 2 m.
Angel sharks possess extensible jaws that can rapidly snap upwards to capture prey and have long, needle-like teeth. They bury themselves in sand or mud lying in wait for prey, which includes fish, crustaceans and various types of mollusks. They are ovoviviparous, producing litters of up to 13 pups. Pacific Angel Shark pups are born from March to June in deep water — generally 180 to 300 feet (55 and 90 metres) — possibly to protect the tiny pups from predators.
Angel Sharks usually reside in depths of 1–200 m and can be seen on muddy or soft bottom substrata where they can easily blend in 
as they lie on the bottom. Since Members of the family Squatinidae have a unique camouflage method, it goes hand in hand with how they obtain their food, by lying still on the sea floor, making rapid lunges at passing prey,and using negative pressure to capture prey by sucking it
into their mouths.
Morphological ID in the field can be to a great degree troublesome thinking about discontinuity of species for exchange or high likeness between congeneric species. In this specific circumstance, the shark aggregate having a place with the class Squatina is made out of three species circulated in the southern piece of the western Atlantic. These three species are arranged in the IUCN Red List as imperiled, and they are right now secured under Brazilian law, which denies angling and exchange. Sub-atomic hereditary apparatuses are presently utilized for commonsense ordered recognizable proof, especially in situations where morphological perception is forestalled, e.g., amid fish handling. Thus, DNA barcoding was utilized in the present examination to track potential wrongdoings against the arrival and exchange of imperiled species along the Sao Paulo coastline, specifically Squatina guggenheim (n = 75) and S. occulta (n = 5), and also the Brazilian guitarfish Pseudobatos horkelii (n = 5). DNA barcoding uncovered the ceaseless angling and trafficking of these ensured species, subsequently giving clear proof that the present protection models and strategies for observing are not working.
Although this shark is a bottom-dweller and appears harmless, it can inflict painful lacerations if provoked, due to its powerful jaws and sharp teeth. It may bite if a diver approaches the head or grabs the tail.