The ocellate topeshark (Hemitriakis complicofasciata) is a species of houndshark, belonging to the family Triakidae. It is found in the western Pacific from the Ryukyu Islands to the Philippines and Taiwan.
T. Takahashi & Nakaya, 2004
The Australian grey smooth-hound or grey gummy shark (Mustelus ravidus) is a species of houndshark, belonging to the family Triakidae, native to the Pacific Ocean and Indian Ocean waters surrounding Australia. The shark is widespread in deep coastal waters (100 to 300 meters).Banded houndshark
The banded houndshark (Triakis scyllium) is a species of houndshark in the family Triakidae, common in the northwestern Pacific Ocean from the southern Russian Far East to Taiwan. Found on or near the bottom, it favors shallow coastal habitats with sandy or vegetated bottoms, and also enters brackish water. This shark reaches 1.5 m (4.9 ft) in length. It has a short, rounded snout and mostly narrow fins; the pectoral fins are broad and triangular, and the trailing margin of the first dorsal fin is almost vertical. It is gray above and lighter below; younger sharks have darker saddles and dots, which fade with age.
Nocturnal and largely solitary, the banded houndshark preys on benthic invertebrates and bony fishes. It is aplacental viviparous, with the developing embryos sustained by yolk. After mating during summer, females bear as many as 42 pups following a gestation period of 9–12 months. The banded houndshark poses no danger to humans and adapts well to captivity. It is caught as bycatch off Japan, Taiwan, and likely elsewhere in its range; it may be eaten but is not as well-regarded as related species. Because fishing does not appear to have diminished this shark's population, the International Union for Conservation of Nature has listed it under least concern.Bigeye houndshark
The bigeye houndshark (Iago omanensis) is a species of houndshark, belonging to the family Triakidae. It is found in the deep waters of the continental shelves in the western Indian Ocean, from the Red Sea to southwestern India, between latitudes 30° N and 10° N, at depths between 110 and 2,200 m. Its length is up to 37 cm.Hemitriakis
Hemitriakis is a genus of houndsharks in the family Triakidae.Houndshark
Houndsharks, the Triakidae, are a family of ground sharks, consisting of about 40 species in nine genera. In some classifications, the family is split into two subfamilies, with Mustelus, Scylliogaleus, and Triakis in the subfamily Triakinae, and the remaining genera in the subfamily Galeorhininae.
Houndsharks are distinguished by possessing two large, spineless dorsal fins, an anal fin, and oval eyes with nictitating eyelids. They are small to medium in size, ranging from 37 to 220 cm (1.21 to 7.22 ft) in adult length. They are found throughout the world in warm and temperate waters, where they feed on fish and invertebrates on the seabed and in midwater.Japanese topeshark
The Japanese topeshark (Hemitriakis japanica) is a species of houndshark, in the family Triakidae. It can reach a length of up to 1.1 m. It is found in the subtropical northwest Pacific from China, Taiwan, Korea, and Japan, between latitudes 40° N and 21° N.Leopard shark
The leopard shark (Triakis semifasciata) is a species of houndshark, in the family Triakidae. It is found along the Pacific coast of North America, from the U.S. state of Oregon to Mazatlán in Mexico. Typically measuring 1.2–1.5 m (3.9–4.9 ft) long, this slender-bodied shark is immediately identifiable by the striking pattern of black saddle-like markings and large spots over its back, from which it derives its common name. Large schools of leopard sharks are a common sight in bays and estuaries, swimming over sandy or muddy flats or rock-strewn areas near kelp beds and reefs. They are most common near the coast, in water less than 4 m (13 ft) deep.
Active-swimming predators, groups of leopard sharks often follow the tide onto intertidal mudflats to forage for food, mainly clams, spoon worms, crabs, shrimp, bony fish, and fish eggs. Most leopard sharks tend to remain within a particular area rather than undertaking long movements elsewhere, which has led to genetic divergence between populations of sharks living in different regions. This species is aplacental viviparous, meaning that the young hatch inside the uterus and are nourished by yolk. From March to June, the female gives birth to as many as 37 young after a gestation period of 10–12 months. It is relatively slow-growing and takes many years to mature.
Harmless to humans, the leopard shark is caught by commercial and recreational fisheries for food and the aquarium trade. This species is mostly fished in the waters off California where, after a period of population decline in the 1980s, new fishing regulations in the early 1990s reduced harvesting to sustainable levels. The International Union for Conservation of Nature has assessed this species as of Least Concern, while noting that local stocks may easily become overfished because of the shark's slow growth and limited migratory habits.List of cartilaginous fish
The following is the full list of the extant species in Class Chondrichthyes, or the cartilaginous fish. Members of this class have a backbone, gills, no swim bladder, jaws, and a skeleton made of cartilage, a soft, strong material as a replacement for bone.List of data deficient fishes
As of September 2016, the International Union for Conservation of Nature (IUCN) lists 3191 data deficient fish species. 21% of all evaluated fish species are listed as data deficient.
The IUCN also lists 12 fish subspecies as data deficient.
Of the subpopulations of fishes evaluated by the IUCN, 34 species subpopulations have been assessed as data deficient.
This is a complete list of data deficient fish species and subspecies evaluated by the IUCN. Species and subspecies which have data deficient subpopulations (or stocks) are indicated.List of sharks
Sharks belong to the superorder Selachimorpha in the subclass Elasmobranchii, in the class Chondrichthyes. The Elasmobranchii also include rays and skates; the Chondrichthyes also include Chimaeras. The first sharks appeared in the oceans over 440 million years ago.
Listed below are extant species of shark. Sharks are spread across 512 described and 23 undescribed species in eight orders. The families and genera within the orders are listed in alphabetical order. Also included is a field guide to place sharks into the correct order.Sharptooth houndshark
The sharptooth houndshark, or spotted gully shark (Triakis megalopterus) is a species of houndshark in the family Triakidae found in shallow inshore waters from southern Angola to South Africa. Favoring sandy areas near rocky reefs and gullies, it is an active-swimming species that usually stays close to the bottom. This robust shark reaches 1.7 m (5.6 ft) in length and has characteristically large, rounded fins; the pectoral fins in particular are broad and sickle-shaped in adults. It also has a short, blunt snout and long furrows around its mouth. This species is gray or bronze in color above, with variable amounts of black spotting.
Mainly active at night, the sharptooth houndshark feeds mostly on crustaceans, bony fishes, and cephalopods. It has been observed gathering in groups in shallow water during summertime, possibly for reproductive purposes. This species is aplacental viviparous, meaning that the unborn young are sustained mainly by yolk. Females give birth to 6–12 pups between late May and August, on a 2- or 3-year cycle. The sharptooth houndshark is often hooked by recreational anglers, and some are also captured on commercial bottom longlines. Because of its small range and low growth and reproductive rates, it is very vulnerable to overfishing. The International Union for Conservation of Nature has therefore listed this species as near threatened.Spotless smooth-hound
The spotless smooth-hound (Mustelus griseus) is a species of houndshark, in the family Triakidae, found on the continental shelves of the northwest Pacific, between latitudes 40° N and 11° N, from the surface to a depth of 300 m. It can grow to a length of up to 1 m (3 ft 3 in).Triakis
Triakis is a genus of houndsharks in the family Triakidae. The name comes from the Greek word τρι, tri meaning "three", and the Latin word acis meaning "sharp" or "pointed", in reference to the three-pointed teeth of these sharks.Whiskery shark
The whiskery shark (Furgaleus macki) is a species of houndshark in the family Triakidae, and the only member of its genus. This common shark inhabits the Australian continental shelf from Western Australia to the Bass Strait, to a depth of 220 m (720 ft). It is demersal in habits and prefers rocky and vegetated habitats. Stout-bodied and almost "humpbacked" in form, the whiskery shark can be distinguished from all other members of its family by the presence of long nasal barbels. Its two moderately large dorsal fins are roughly equal in size. It is brownish gray above and lighter below, with a pattern of darker saddles and blotches in younger sharks. This species reaches 1.6 m (5.2 ft) in length.
The diet of the whiskery shark consists almost entirely of octopuses. It is viviparous; females bear litters of four to 28 pups every other year from August to October, after a gestation period of 7–9 months. This harmless shark is used for its meat, being one of the species marketed as "flake" in Australia. It is mainly caught by a Western Australian commercial gillnet fishery. Its numbers declined significantly from overfishing in the 1970s and early 1980s, leading to the introduction of new management measures in the mid-1980s. Since then, strict fishery management has kept the whiskery shark population stable or increasing, resulting in its listing as of least concern by the International Union for Conservation of Nature.White-fin smooth-hound
The white-fin smooth-hound (Mustelus widodoi) is a species of tropical houndshark, and part of the family Triakidae, found in the Bali and Indonesia areas of the Western Pacific.
Extant houndshark species