Small-spotted catshark | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Chondrichthyes |
Subclass: | Elasmobranchii |
Order: | Carcharhiniformes |
Family: | Scyliorhinidae |
Genus: | Scyliorhinus |
Species: | S. canicula |
Binomial name | |
Scyliorhinus canicula | |
Range in blue |
The small-spotted catshark (Scyliorhinus canicula), also known as the sandy dogfish, [2] lesser-spotted dogfish, rough-hound or morgay (in Scotland and Cornwall), [3] is a catshark of the family Scyliorhinidae. It is found on the continental shelves and the uppermost continental slopes off the coasts of Norway and the British Isles south to Senegal and in the Mediterranean, between latitudes 63° N and 12° N. It can grow up to a length of 1 m (3 ft 3 in), and it can weigh more than 2 kg (4.4 lb). [4] It is found primarily over sandy, gravelly, or muddy bottoms from depths of a few metres down to 400 m (1,300 ft). [5] S. canicula is one of the most abundant elasmobranchs in the northeast Atlantic and Mediterranean Sea. The majority of the populations are stable in most areas. [6]
S. canicula are small, shallow-water sharks with a slender body and a blunt head. The two dorsal fins are located towards the tail end of the body. The texture of their skin is rough, similar to the coarseness of sandpaper. [7] The nostrils are located on the underside of the snout and are connected to the mouth by a curved groove. The upper side of the body is greyish brown with dark brown spots. The underside is a light greyish white. The teeth of S. canicula are larger in males than in females; in addition, male S. canicula from West African waters have stronger, larger, and more calcinated jaws. The differences in mouth dimensions and tooth length between males and females, and between immature and adult males, could be due to different feeding habits or adaptations for reproductive behaviour. [8]
S. canicula is oviparous. They deposit egg cases protected by a horny capsule with long tendrils. Egg cases are mostly deposited on macroalgae in shallow coastal waters. When the egg cases are deposited farther from shore, they are placed on sessile erect invertebrates. Egg cases usually measure 4 cm by 2 cm, without ever exceeding 6 cm (2.4 in). [9] These egg cases can be found around the coasts of Europe. The embryos develop for 5–11 months depending on the sea temperature, and the young are born with a measurement of 9–10 cm (3.5–3.9 in).
Spawning can take place almost year round. [9] However, there can be seasonal patterns in spawning activity as well. For example, S. canicula females located off the Mediterranean coast of France lay their eggs from March to June and in December. In the waters surrounding Great Britain, egg laying occurs in spring with a gap between August and October. On the Tunisian coast, the sharks lay their eggs starting in spring, peaking in the summer and then slightly decreasing during autumn. [10] Males reach sexual maturity with a length of about 37.1–48.8 cm (14.6–19.2 in). Females reach sexual maturity with a length of 36.4–46.7 cm (14.3–18.4 in). [11]
S. canicula is an opportunistic species, preying on a wide variety of organisms. Decapod crustaceans, molluscs and fishes are their main prey, but echinoderms, polychaetes, sipunculids and tunicates may also be eaten. [5] Dietary preferences change with age; younger animals prefer small crustaceans, while older animals prefer hermit crabs and molluscs. Feeding intensity is highest during the summer due to the higher availability of prey life. Diet composition varies with body size.
There are no significant differences in feeding habits between male and female S. canicula. [5] Juveniles of S. canicula feed by anchoring the prey item on the dermal denticles near their tail, and tearing bite-sized pieces off with rapid head and jaw movements, a behaviour known as "scale rasping". Use of dermal denticles to assist in feeding was first documented in this species. [12]
A study published in 2014 at Exeter University showed that individual small-spotted catsharks have different personality traits. Some individuals are more sociable than others, some more aggressive, some more exploratory in nature. [13] [14]
S. canicula is well-suited for comparative analysis of gastrulation for several reasons.
S. canicula is one of the most abundant elasmobranchs in the northeast Atlantic and Mediterranean. It is regularly caught by near-shore fisheries, but the majority taken by commercial fishermen and recreational anglers are discarded. Studies have shown that post-discard survival rates are extremely high, around 98%. Although localized depletion may have occurred in some areas, surveys have shown that populations are stable or are even increasing throughout the majority of its range. However, continued monitoring of landing and discarded data is important to avoid any future decline.
This species is currently listed as being of least concern on the IUCN Red List of Threatened Species, because there is no evidence to indicate that the global population has declined significantly. Since 2003, there have been yearly releases of these sharks into the Gullmarn fjord in Sweden by the public aquaria Havets Hus in Lysekil. More than 90 sharks have been released since 2003, of which one was found in southern Norway 10 years after its release. This means that these sharks can reach at least an age of 14 years. [16]
S. canicula is currently of low commercial value. In the recent past, it was one of the species sold in English and Scottish fish and chip shops as rock salmon, rock eel, huss, or sweet william. In other parts of its range, it is occasionally baked or used in fish soup. [3] Its hard skin has been used as a substitute for pumice, but the fact that catsharks have to be skinned before they can be filleted discourages commercial fishermen from catching this species. [17]
Scyliorhinidae is a family of sharks, one of a few families whose members share the common name catsharks, belonging to the order Carcharhiniformes, the ground sharks. Although they are generally known as catsharks, some species can also be called dogfish due to previous naming. However, a dogfish may generally be distinguished from a catshark as catsharks lay eggs while dogfish have live young. Like most bottom feeders, catsharks feed on benthic invertebrates and smaller fish. They are not harmful to humans. The family is paraphyletic, containing several distinct lineages that do not form a monophyletic group.
Dogfish may refer to:
An egg case or egg capsule, often colloquially called a mermaid's purse, is the casing that surrounds the eggs of oviparous chondrichthyans. Living chondricthyans that produce egg cases include some sharks, skates and chimaeras. Egg cases typically contain one embryo, except for big skate and mottled skate egg cases, which contain up to 7 embryos. Oviparity is completely absent in the superorder Squalomorphii. Egg cases are also thought to have been produced by some extinct chondricthyan groups, such as hybodonts and xenacanths.
The chain catshark or chain dogfish is a small, reticulated catshark that is biofluorescent. The species is common in the Northwest Atlantic, Gulf of Mexico, and Caribbean. It is harmless and rarely encountered by humans. It has very similar reproductive traits to the small-spotted catshark.
The redspotted catshark, also known as the Chilean catshark, is a species of catshark commonly found in the coastal waters of the southeastern Pacific, from central Peru to southern Chile. They are typically found in the rocky sublittoral areas at the edge of the continental shelf, in waters down to 100 m in depth. They spend the spring, summer, and fall in rocky subtidal areas, but winter in deeper offshore waters due to the strong currents at that time of year.
The blotchy swellshark or Japanese swellshark is a common species of catshark, belonging to the family Scyliorhinidae. The Blotchy swellshark is found at depths of 90–200 m (300–660 ft) in the northwestern Pacific Ocean, from Japan to Taiwan. It is benthic in nature and favors rocky reefs. Reaching 1.4 m (4.6 ft) in length, this thick-bodied shark has a broad head, large mouth, and two unequally-sized dorsal fins positioned far back past the pelvic fins. It can be identified by its dorsal coloration, consisting of seven brown "saddles" and extensive darker mottling on a light tan background. This species has often been confounded with the draughtsboard shark and the Sarawak pygmy swellshark in scientific literature.
The lizard catshark is a small shark species of the catshark family, Scyliorhinidae, found off the coast of southern Brazil on the upper continental shelf at depths of between 250 and 500 metres.
The dwarf catshark is a catshark, belonging to the family Scyliorhinidae. It is found off the coast of southern Florida, the Bahamas, and Cuba and is also known as the whitespotted catshark and Cuban catshark.
The quagga catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. A small, slim-bodied shark reaching 37 cm (15 in) in length, it has a distinctive color pattern of narrow, dark brown vertical bars, which resemble those of the quagga. Its head is short and flattened, with a pointed snout tip that is not upturned.
The tiger catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. It is found over sandy areas and near reef peripheries off South Africa and perhaps Mozambique, from close to shore to usually no deeper than 100 m (330 ft). Reaching a length of 50 cm (20 in), this small, slim shark has a broad, flattened head with an upturned snout tip. It can additionally be identified by its dorsal colour pattern of ten dark brown saddles on a yellowish brown background.
The dusky catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. This shark is endemic to the southeast Pacific Ocean, off the coasts of Peru and Chile. It grows to a maximum length of 70 cm (28 in), and is oviparous like many other chondrichthyans in the Indo-Pacific.
The cloudy catshark is a common species of catshark, belonging to the family Scyliorhinidae. It is a bottom-dweller that inhabits rocky reefs in the northwestern Pacific Ocean, from the shore to a depth of 320 m (1,050 ft). Growing up to 50 cm (20 in) long, this small, slim shark has a narrow head with a short blunt snout, no grooves between the nostrils and mouth, and furrows on the lower but not the upper jaw. It is also characterized by extremely rough skin and coloration consisting of a series of dark brown saddles along its back and tail, along with various darker and lighter spots in larger individuals.
The nursehound, also known as the large-spotted dogfish, greater spotted dogfish or bull huss, is a species of catshark, belonging to the family Scyliorhinidae, found in the northeastern Atlantic Ocean. It is generally found among rocks or algae at a depth of 20–60 m (66–197 ft). Growing up to 1.6 m (5.2 ft) long, the nursehound has a robust body with a broad, rounded head and two dorsal fins placed far back. It shares its range with the more common and closely related small-spotted catshark, which it resembles in appearance but can be distinguished from, in having larger spots and nasal skin flaps that do not extend to the mouth.
The whitesaddled catshark is a species of catshark, and part of the family Scyliorhinidae. It is found on the upper continental slope of the western central Atlantic Ocean, off the coasts of Honduras, Panama and Colombia, between latitudes 22° N and 9° N, at depths between 274 and 457 m. It can grow to a length of 47 cm (19 in). The reproduction of this catshark is oviparous but otherwise, little is known about its biology.
The yellowspotted catshark is a rare catshark of the family Scyliorhinidae. It is found in the southeast Atlantic, from Lüderitz, Namibia to central Natal, South Africa, between latitudes 0° and 37° S. It can grow up to a length of about 1.22 metres. The reproduction of this catshark is oviparous.
The boa catshark is a catshark of the family Scyliorhinidae. It is found on the continental shelves and insular slopes of the Caribbean Sea and the Gulf of Mexico, between latitudes 20° N and 9° N, at depths between 330 and 675 m. It can grow up to a length of 54 cm. The reproduction of this catshark is oviparous.
The blackmouth catshark is a species of deepwater catshark, belonging yo the family Pentanchidae, common in the northeastern Atlantic Ocean from Iceland to Senegal, including the Mediterranean Sea. It is typically found over the continental slope at depths of 150–1,400 m (490–4,590 ft), on or near muddy bottoms. The youngest sharks generally inhabit shallower water than the older juveniles and adults. This slim-bodied species is characterized by the black interior of its mouth, a marbled pattern of pale-edged brownish saddles or blotches along its back and tail, and a prominent saw-toothed crest of enlarged dermal denticles along the upper edge of its caudal fin. It reaches lengths of 50–79 cm (20–31 in), with sharks in the Atlantic growing larger than those in the Mediterranean.
Scyliorhinus meadi, the blotched catshark, is a little-known species of catshark, and part of the family Scyliorhinidae, found in the western central Atlantic Ocean. It inhabits banks of deep-sea coral at depths of 329–548 m (1,079–1,798 ft), feeding on cephalopods, shrimp, and bony fishes. This species can be identified by its wide body and head, and the dark saddle-like markings on its back. It also has small spots that fluoresce yellow under a blue light. Adult blotched catsharks have not been observed; the largest immature specimen is 49 cm (19 in) long. Like other catsharks, it is believed to be oviparous. This species is not dangerous to humans and has no commercial significance.
The Pacific spiny dogfish is a common species of the Squalidae (dogfish) family of sharks and are among the most abundant species of sharks in the world. This species is closely related to Squalus acanthias and for many years they were treated as a single species. Recent research, using meristic, morphological and molecular data led to the resurrection of the Pacific spiny dogfish as a separate species. The American Fisheries Society recommends the common name "Pacific spiny dogfish" for Squalus suckleyi over alternatives such as "spotted spiny dogfish" and "North Pacific spiny dogfish" and "spiny dogfish" for Squalus acanthias.
The cinder cloudy catshark is a species of catshark from the Pacific Ocean; all specimens identified have been from the area around the Izu Islands, Japan. The species is a close relative of the cloudy catshark, and the overall appearance is similar. The species was first identified in 2022 as bycatch of the splendid alfonsino fishery.