| Raja straeleni | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Superorder: | Batoidea |
| Order: | Rajiformes |
| Family: | Rajidae |
| Genus: | Raja |
| Species: | R. straeleni |
| Binomial name | |
| Raja straeleni (Poll, 1951) | |
Raja straeleni, the biscuit skate, false thornback skate, or spotted skate, is a species of marine fish in the skate family (family Rajidae) of order Rajiformes. It is native to the eastern Atlantic Ocean.
This skate has a blunt, angular snout, a long, thick tail, and a broad flattened angular disc with wing-like pectoral fins. [2] [3] They reach a disc width of up to 68 cm (27 in) and are a light brown in colour with black spots, whorls and rosettes. The pectoral fins also have a dark brown eye spot near the base, although these are absent in juveniles. [3] [4] The upper side of the body is covered in many thorn-like spines, with a row of strong thorns along the back and down the tail. [4] Larger individuals may also have thorns on the white underside. [2] [3]
This species is found in the eastern Atlantic, from Rio de Oro in Western Sahara to South Africa. It is an oceanodromous marine demersal species. It is found from areas close inshore to a depth of 800 m (2,600 ft), although they are most common at depths of 100–300 m (330–980 ft). [2] They prefer sandy areas and are found in shallow enclosed bays and on the continental slope. [2] [4]
This skate migrates towards the coastal shallows during the warm season and towards deep waters in winter. [2] [3] They spend most of their time lying flat on the sand, where they are well camouflaged. [3]
This skate feeds on invertebrates, including crustaceans, bony fishes and fish offal. [2] [4]
This species is oviparous: The egg cases are dark brown and have horn-like projections on the shell. [2] [3]
Raja: Latin, raja, -ae = a sting ray; straeleni: Named after V. Van Straelen, director of IRSNB, Belgium. [2]
This species is caught by commercial fisheries and as a gamefish. It is caught by shore and ski-boat anglers and by hake trawlers. The pectoral fins sold as 'skate wings'. [2]
This species is classified as being near threatened by the IUCN. While population data in South Africa seem to indicate that the population is stable in the region, there is intense unmanaged fishing in the northern parts of its range. This, coupled with the deceased landings and the fishery range expansions that have stemmed from depleting fish stocks, suggests that it has declined massively in parts of its range due to exploitation This is exasperated by its slow rate of reproduction. [5]
The thorntail stingray, black stingray, or longtail stingray is a species of stingray in the family Dasyatidae. It is found off southern Africa, Australia, and New Zealand from the intertidal zone to a depth of 440 m (1,440 ft). This bottom-dweller inhabits soft-bottomed habitats such as lagoons, estuaries, and reefs. Growing to 1.8 m (5.9 ft) across and over 200 kg (440 lb) in weight, the thorntail stingray is among the largest stingrays in the world. Uniformly dark above and light below, it has a diamond-shaped pectoral fin disc and a very long, whip-like tail with a fin fold underneath. The upper surface of the disc and the tail bear numerous stout, sharp thorns.
Aetomylaeus bovinus, also known as the bull ray, duckbill ray, or duckbill eagle ray, is a species of large stingray of the family Myliobatidae found around the coasts of Europe and Africa.
The barbeled houndshark is a species of ground shark and the only member of the family Leptochariidae. This demersal species is found in the coastal waters of the eastern Atlantic Ocean from Mauritania to Angola, at depths of 10–75 m (33–246 ft). It favors muddy habitats, particularly around river mouths. The barbeled houndshark is characterized by a very slender body, nasal barbels, long furrows at the corners of the mouth, and sexually dimorphic teeth. Its maximum known length is 82 cm (32 in).
The Atlantic weasel shark is a weasel shark of the family Hemigaleidae, found in the eastern Atlantic Ocean. Also known as the little tiger shark, it is the only species of the genus Paragaleus to have been recorded off the western coast of Africa. It is one of four species of small sharks within the carcharhinoid genus Paragaleus, including Paragaleus leucolomatus, Paragaleus tengi, and Paragaleus randalli. It also one of eight species within the weasel shark family, Hemigaleidae. It is currently considered by the International Union for Conservation of Nature (IUCN) as Endangered.
The common smooth-hound is a houndshark of the family Triakidae. It is found in the eastern Atlantic Ocean from the British Isles to South Africa, and in the Mediterranean Sea, Madeira, and the Canary Islands at depths ranging from 5 to 625 m. While they can grow to 200 cm, their usual maximum size is 150 cm. They commonly grow to 100–120 cm with a birth length around 35 cm. The reproduction of commons smooth-hounds is viviparous.
The white-spotted guitarfish is a type of ray. It is found in the eastern Atlantic from the Gulf of Guinea to Angola. It reaches a length of approximately 75 cm.
The pincushion ray or thorny freshwater stingray, is a little-known species of stingray in the family Dasyatidae, found in the rivers and lakes of West and Middle Africa. A heavy-bodied ray measuring up to 1.2 m (4 ft) across, this species can be distinguished by its rounded pectoral fin disk, reduced or absent stinging tail spine, and—in adults—numerous stout thorns covering its back and tail. In lieu of a long tail spine as in other stingrays, the pincushion ray employs these thorny denticles in defense. Seldom encountered since it was originally described, this species has been assessed as Critically Endangered by the International Union for Conservation of Nature (IUCN).
The Broad stingray, also known as the Brown stingray or Hawaiian stingray, is a species of stingray in the family Dasyatidae. The predominant species of stingray in the inshore waters of the Hawaiian Islands, this benthic fish typically inhabits sandy or muddy flats at depths greater than 15 m (49 ft). Usually growing to 1 m (3 ft) across, the broad stingray has a wide, diamond-shaped pectoral fin disc with a protruding snout tip and a long tail with a ventral fin fold. At night, this species actively forages for bottom-dwelling invertebrates and bony fishes, often near the boundaries of reefs. Reproduction is aplacental viviparous. As substantial threats to its population exist in many areas of its wide distribution, IUCN has listed this species as Vulnerable.
The common torpedo, also known as ocellate torpedo or eyed electric ray, is a species of electric ray in the family Torpedinidae. It is found in the Mediterranean Sea and the eastern Atlantic Ocean from the Bay of Biscay to Angola, and is a benthic fish typically encountered over soft substrates in fairly shallow, coastal waters. Growing to 60 cm (24 in) long, this species has a nearly circular pectoral fin disc and a short, thick tail with two dorsal fins of nearly equal size and a large caudal fin. It can be identified by the prominent blue spots on its back, which usually number five but may vary from zero to nine, as well as by the small knobs on the rims of its spiracles.
The common stingray is a species of stingray in the family Dasyatidae, found in the northeastern Atlantic Ocean and the Mediterranean and Black Seas. It typically inhabits sandy or muddy habitats in coastal waters shallower than 60 m (200 ft), often burying itself in sediment. Usually measuring 45 cm (18 in) across, the common stingray has a diamond-shaped pectoral fin disc slightly wider than long, and a whip-like tail with upper and lower fin folds. It can be identified by its plain coloration and mostly smooth skin, except for a row of tubercles along the midline of the back in the largest individuals.
The pearl stingray is a little-known species of stingray in the family Dasyatidae, found in shallow coastal waters from Mauritania to Angola, though fossils have been found in Portugal. Growing to 30 cm (12 in) across, this species has a rounded pectoral fin disc with a pointed snout, and a wide band of dermal denticles over the back in adults. It closely resembles and is often confused for the much larger daisy stingray ; both species are characterized by the presence of an enlarged, nacreous denticle in the middle of the back called a "pearl spine". The International Union for Conservation of Nature (IUCN) assesses the pearl stingray's conservation status as Near Threatened, but it is likely that most of the historically reported fishery catches of the daisy stingray were in fact of this species.
The daisy stingray, Fontitrygon margarita, is a little-known species of stingray in the family Dasyatidae, found in shallow waters along the coast of West Africa. This species typically grows to 60 cm (24 in) across and has a rounded pectoral fin disc and a wide band of dermal denticles over its back. It is characterized by a greatly enlarged, nacreous denticle in the middle of its back called a "pearl spine"; this feature is shared with the similar but much smaller pearl stingray, which has often been confused with this species. The daisy stingray feeds mainly on crustaceans and exhibits aplacental viviparity, with litters of 1–4 young. Heavily pressured by fisheries and possibly habitat degradation, this once-common species is declining and has been assessed as Vulnerable by the International Union for Conservation of Nature (IUCN).
The smalltooth stingray is an obscure species of stingray in the family Dasyatidae, found in the Gulf of Guinea. It is known only from a stuffed specimen described by Albert Günther in 1870, which has since been lost. In 1970, Springer and Collette assigned a jaw, tail, and two embryos from off Sierra Leone to this species, but later investigation found that the jaw belonged to a guitarfish, and the tail and embryos to a different species, possibly Dasyatis hastata.
The striped panray is a species of ray in the family Zanobatidae. It was considered the only species in its genus and family until the description of the maculate panray in 2016.
The common guitarfish is a species of cartilaginous fish in the family Rhinobatidae. It is native to the eastern Atlantic Ocean and the Mediterranean Sea. It is a bottom-dwelling fish feeding on crustaceans, other invertebrates and fish. The females give birth to live young. Its lifestyle makes it vulnerable to trawling and other fishing methods, populations seem to be declining and it has disappeared from parts of its range.
Dasyatis ushiei, the cow stingray or Ushi stingray, is a species of stingray known from a single specimen. Based on the single specimen, its range includes at least Mikawa Bay, Aichi Prefecture, middle Japan. Due to the limited knowledge of its biology and extent of capture in fisheries, this species is assessed as Data Deficient in 2007.
The common eagle ray or bullray is a species of fish in the family Myliobatidae. It inhabits the eastern Atlantic Ocean, the Mediterranean Sea and the south-western Indian Ocean.
The Lusitanian cownose ray is a species of eagle ray found along the western coast of Africa and Mediterranean Sea. It is apparently very rare in the Mediterranean Sea, but is common in shallow waters off the western Africa.
Torpedo mackayana, commonly known as the ringed torpedo, Western African torpedo, West African torpedo ray, McKay electric ray, or McKay's torpedo ray, is an electric ray species in the family Torpedinidae, which lives in shallow waters on the western coast of Africa. Characterized by rounded spiracles and white and brown spots, females grow to 35–50 centimetres (14–20 in) and males to 31.5–38.2 centimetres (12.4–15.0 in).
"Raja straeleni". Integrated Taxonomic Information System. 19 March 2014.
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