Squatina squatina

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Angelshark
Squatina squatina tenerife.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Subdivision: Selachimorpha
Order: Squatiniformes
Family: Squatinidae
Genus: Squatina
Species:
S. squatina
Binomial name
Squatina squatina
Squatina squatina distmap.png
Former range of the angelshark
Synonyms

Squalraia acephala* de la Pylaie, 1835
Squalraia cervicata* de la Pylaie, 1835
Squalus squatina Linnaeus, 1758
Squatina angelusBlainville, 1825
Squatina angelusGronow, 1854
Squatina europaeaSwainson, 1839
Squatina laevisCuvier, 1816
Squatina lewisCouch, 1825
Squatina vulgarisRisso, 1810

Contents

* ambiguous synonym

Squatina squatina, the angelshark or monkfish, is a species of shark in the family Squatinidae (known generally also as angel sharks), that were once widespread in the coastal waters of the northeastern Atlantic Ocean. Well-adapted for camouflaging itself on the sea floor, the angelshark has a flattened form with enlarged pectoral and pelvic fins, giving it a superficial resemblance to a ray. This species can be identified by its broad and stout body, conical barbels, thornless back (in larger individuals), and grayish or brownish dorsal coloration with a pattern of numerous small light and dark markings (that is more vivid in juveniles). It measures up to 2.4 m (7.9 ft) long.

Like other members of its family, the angelshark is a nocturnal ambush predator that buries itself in sediment and waits for passing prey, mostly benthic bony fishes, but also skates and invertebrates. An aplacental viviparous species, females bear litters of seven to 25 pups every other year. The angelshark normally poses little danger to humans, though if provoked, it is quick to bite. Since the mid-20th century, intense commercial fishing across the angelshark's range has decimated its population via bycatch – it is now locally extinct or nearly so across most of its northern range, and the prospects of the remaining fragmented subpopulations are made more precarious by its slow rate of reproduction. As a result, the International Union for Conservation of Nature has assessed this species as Critically Endangered.

Taxonomy and phylogeny

The angelshark was originally described by the Swedish natural historian Carl Linnaeus, known as the "father of taxonomy", in the 1758 tenth edition of Systema Naturae as Squalus squatina. He did not designate a type specimen. [2] The word squatina is the name for skate in Latin; it was made the genus name for all angel sharks by the French zoologist André Duméril in 1806. [3] Other common names used for this species include angel, angel fiddle fish, angel puffy fish, angel ray, angelfish, escat jueu, fiddle fish, monk, and monkfish. [4] Stelbrink and colleagues (2010) conducted a phylogenetic study based on mitochondrial DNA, and found that the sister species of the angelshark is the sawback angelshark (S. aculeata). The two species formed a clade with a number of Asian angelshark species. [5]

Description

Early illustration of an angelshark from Les poissons (1877) Squatina angelus - Gervais.jpg
Early illustration of an angelshark from Les poissons (1877)

One of the largest members of its family, female angelsharks can attain a length of 2.4 m (7.9 ft) and males 1.8 m (5.9 ft); the maximum reported weight is 80 kg (180 lb). [4] This species shares in common with other angelsharks a flattened body and large, wing-like pectoral fins whose anterior lobes are not fused to the head. The head and body are very broad and stocky, with small eyes positioned dorsally and followed by a pair of larger spiracles. [6] A pair of unadorned barbels occurs in front of the nares, as well as a smooth or weakly fringed flap. Folds of skin with a single triangular lobe are present on the sides of the head. The teeth are small, sharp, and of similar shape in both jaws. [2]

The pectoral and pelvic fins are wide with rounded tips; the two dorsal fins are positioned on the muscular tail behind the pelvic fins. The anal fin is absent, and the caudal fin has a larger lower lobe than upper. The dermal denticles are small, narrow, and pointed, and cover the entire upper and most of the lower body surface. There are patches of small spines on the snout and over the eyes. Small individuals have a row of thorns down the middle of the back. [2] [6] The coloration is gray to reddish or greenish brown above, with many small black and white spots, and white below. Juveniles are more ornately patterned than adults, with pale lines and darker blotches. The dorsal fins have a darker leading margin and lighter trailing margin. Some individuals have a white spot on the back of the "neck". [7]

Distribution and habitat

The angelshark occurs in the temperate waters of the northeastern Atlantic, from southern Norway and Sweden to the Western Sahara and the Canary Islands, including around Britain and Ireland and in the Mediterranean. According to the IUCN, it is possible that it has been extirpated from the North Sea. It remains extant around the Canary Islands, Algeria, Tunisia, Libya, Israel, Turkey, northern Cyprus, eastern Greece (the Aegean Sea), the Adriatic Sea of eastern Italy, Sicily, Malta, Corsica, Ireland and western Britain/Wales . Its modern presence in parts of the Mediterranean is unknown, such as around Madeira, the Azores, Morocco, Egypt, continental Spain and France, Crete, Syria, Sardinia, western Greece and western Italy. [1] This benthic shark inhabits the continental shelf, preferring soft substrates such as mud or sand, and can be found from near the coast to a depth of 150 m (490 ft). It sometimes enters brackish environments. Northern angelshark subpopulations migrate northward in summer and southward in winter. [2]

Biology and ecology

The angelshark is well-camouflaged against soft-bottomed seafloors. Squatina squatina camouflage.jpg
The angelshark is well-camouflaged against soft-bottomed seafloors.

During daytime, the angelshark usually lies motionless on the sea floor, buried under a layer of sediment with only its eyes showing. At night, it becomes more active, and may sometimes be seen swimming above the bottom. [2] Aggregations numbering up to a hundred have been observed off Gran Canaria in the summer. [8] Known parasites of this species include the tapeworms Grillotia smaris-gora, G. angeli, and Christianella minuta , [9] the fluke Pseudocotyle squatinae, [10] the monogenean Leptocotyle minor, [11] and the isopod Aega rosacea. [12]

The angelshark is an ambush predator that feeds mainly on bottom-dwelling bony fishes, especially flatfishes, though it also preys on skates and invertebrates. Prey reported taken include the hake Merluccius merluccius , the bream Pagellus erythrinus , grunts in the genus Pomadasys , the flatfishes Bothus spp., Citharus linguatula , and Solea solea , the squid Loligo vulgaris , the cuttlefishes Sepia officinalis and Sepiola spp., and the crabs Medorippe lanata , Geryon trispinosus , Dromia personata , Goneplax rhomboides , Liocarcinus corrugatus , and Atelecyclus rotundatus . The stomachs of some examined specimens have also contained seagrass or birds (in one case an entire cormorant). [1] Individual sharks select sites that offer the best ambush opportunities, and if successful, may remain there for several days. [8]

Angelsharks are aplacental viviparous, meaning the young hatch inside the mother's uterus and are nourished by a yolk sac until birth. Females have two functional ovaries, with the right ovary containing more oocytes and the right uterus correspondingly containing more embryos; this functional asymmetry is not present in other angel shark species. Unlike most sharks, in which vitellogenesis (yolk formation) occurs concurrently with pregnancy, in the angelshark, the onset of vitellogenesis is delayed until halfway through the gestation period. The mature ova measure 8 cm (3.1 in) across and are not enclosed in a capsule. The reproductive cycle has been estimated at 2 years with ovulation taking place in spring, though this periodicity is ill-defined. The litter size ranges from seven to 25 and is correlated with the size of the mother; the young are gestated for 8–10 months. Parturition occurs from December to February in the Mediterranean and in July off England, with the newborns measuring 24–30 cm (9.4–11.8 in) long. Males and females mature at lengths of 0.8–1.3 m (2.6–4.3 ft) and 1.3–1.7 m (4.3–5.6 ft), respectively. [1] [13]

Human interactions

An angelshark off Tenerife in the Canary Islands, one of the few remaining locations with a substantial population Squatina squatina tenerife2.jpg
An angelshark off Tenerife in the Canary Islands, one of the few remaining locations with a substantial population

The angelshark is generally not aggressive towards humans, though it can deliver a severe bite if disturbed. [2] When approached underwater, the angelshark usually remains still or swims away, though one circling a diver with its mouth open is recorded. [8] Fishery workers, in particular, should treat it with caution; in the 1776 edition of British Zoology, Thomas Pennant wrote that it is "extremely fierce and dangerous to be approached. We know of an instance of a fisherman, whose leg was terribly torn by a large one of this species, which lay within his nets in shallow water, and which he went to lay hold of incautiously." [14]

Humans have used the angelshark for thousands of years. Ancient Greek authors, such as Diphilus and Mnesitheus, described its meat as "light" and "easily digestible", and Pliny the Elder noted in his Naturalis Historia (77–79 AD) that its rough skin was valued by craftsmen for polishing wood and ivory. Aristotle recorded elements of its natural history, including that it bore live young, and correctly recognized that it was a shark despite its resemblance to rays and skates. [15] [16] The use of this species for food has continued into modern times; it is sold fresh or dried and salted, often under the name "monkfish" (which also refers to the goosefishes of the genus Lophius). The angelshark may also be a source for shark liver oil and fishmeal. [4] [17]

Conservation status

Sources from the 19th and early 20th centuries indicate that the angelshark was once abundant all around the coasts of Western Europe. Yarrell (1836), Day (1880–04), and Garstang (1903) all noted that the angelshark was common around the Britain and Ireland, and Rey (1928) recorded that this species was common around the Iberian Peninsula and in the Mediterranean. However, from the latter half of the 20th century onwards, the angelshark has come under intense pressure from commercial fisheries operating across much of its range. Due to its benthic, near-shore habits, individuals of all ages are susceptible to incidental capture by bottom trawls, trammel nets, and bottom longlines; the low reproductive rate of this shark limits its capacity to withstand population depletion. [1] This has also led to habitat loss caused by the development of coastal areas for commercialism and tourism.

Angelshark numbers have declined precipitously across most of its range; it is now believed to be extinct in the North Sea and most of the northern Mediterranean, and has become extremely rare elsewhere. During the comprehensive Mediterranean International Trawl Survey program from 1995 to 1999, only two angelsharks were captured from 9,905 trawls. Similarly, another survey by the Italian National Project (National Group for Demersal Resource Evaluation) around the same period caught angelsharks in only 38 of 9,281 trawls. Fishery data compiled by the Working Group for Elasmobranch Fishes (WGEF) show that no angelsharks have been landed in the Northeast Atlantic since 1998. [1] Fewer than a dozen angelsharks are thought to remain in Irish waters. [18] Healthy subpopulations of angelsharks are thought to still persist in areas off North Africa and around the Canary Islands, though a more thorough assessment is urgently needed. [1] [19]

As a result of these steep population declines and the ongoing threat from demersal fisheries, the IUCN has assessed the angelshark as Critically Endangered. An assessment of the angelshark population by the IUCN showed a decrease in population of over 90%. The assessment also showed that there was no signs of recovery of the population. It was listed on Annex III of the 1976 Barcelona Convention, which aims to limit pollution in the Mediterranean Sea. In 2012 it was moved to Annex II, making it illegal to catch and keep in countries bordering the Mediterranean Sea (if caught, it must be released). This species is protected within three marine reserves in the Balearic Islands, although it has not been reported from this area since the mid-1990s. [1] In 2008, the angelshark also received full legal protection from human activities in the waters off England and Wales from the coast to a distance of 11 km (6.8 mi), under the UK Wildlife and Countryside Act. [20] [21] Since 2010, it has been illegal to keep angelsharks caught in waters of the European Union (if caught, it must be released). The United Kingdom and Belgium have pushed, unsuccessfully, for this species to be listed on the Convention for the Protection of the Marine Environment of the North-East Atlantic Priority List of Threatened and Endangered Species. [1] A captive breeding program has been initiated at Deep Sea World, North Queensferry, with the first live pups born in 2011. [22]

In 2019, a population of angelsharks was discovered off the coast of Wales, indicating that the species had begun a potential return to the region. [23]

Related Research Articles

<span class="mw-page-title-main">Angelshark</span> Genus of sharks

Angelsharks are sharks belonging to the genus Squatina. They are the only living members of the family Squatinidae and order Squatiniformes. They commonly inhabit sandy seabeds close to 150 m (490 ft) in depth.

<i>Lophius</i> Genus of fishes

Members of the genus Lophius, also sometimes called monkfish, fishing-frogs, frog-fish, and sea-devils, are various species of lophiid anglerfishes found in the Atlantic and Indian Oceans. Lophius is known as the "monk" or "monkfish" to the North Sea and North Atlantic fishermen, a name which also belongs to Squatina squatina, the angelshark, a type of shark. The North European species is Lophius piscatorius, and the Mediterranean species is Lophius budegassa.

<span class="mw-page-title-main">Bramble shark</span> Species of shark

The bramble shark 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 400–900 m (1,300–3,000 ft), 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 3.1 m (10 ft) long.

<span class="mw-page-title-main">Black dogfish</span> Species of shark

The black dogfish is a species of dogfish shark in the family Etmopteridae. It is common over the outer continental shelf and continental slope at depths of 180–2,250 m (590–7,380 ft). Females generally inhabit deeper water than males, and depending on the region, smaller sharks may occur at different depths than larger ones. This species is distributed widely in the Atlantic Ocean, from Greenland and Iceland to Virginia and West Africa in the north, and off southwestern Africa and Argentina in the south. The largest member of its family, the black dogfish, typically measures 60–75 cm (24–30 in) long. It has a stocky, dark brown body that is darker below than above, and bears scattered, minute bioluminescent organs. Its two dorsal fins are preceded by stout spines, and the anal fin is absent.

<span class="mw-page-title-main">Portuguese dogfish</span> Species of shark

The Portuguese dogfish or Portuguese shark, is a species of sleeper shark of the family Somniosidae. This globally distributed species has been reported down to a depth of 3,675 m (12,057 ft), making it the deepest-living shark known. It inhabits lower continental slopes and abyssal plains, usually staying near the bottom. Stocky and dark brown in color, the Portuguese dogfish can be distinguished from similar-looking species by the small spines in front of its dorsal fins. Its dermal denticles are also unusual, resembling the scales of a bony fish. This species typically reaches 0.9–1 m (3.0–3.3 ft) in length; sharks in the Mediterranean Sea are much smaller and have distinct depth and food preferences.

<span class="mw-page-title-main">Sand devil</span> Species of shark

The sand devil or Atlantic angel shark is a species of angelshark, family Squatinidae, native to the northwestern Atlantic Ocean. It occurs off the eastern United States, in the northern Gulf of Mexico, and possibly in parts of the Caribbean Sea. This bottom-dwelling shark is found in shallow inshore waters in summer and fall, and deep offshore waters in winter and spring. The sand devil's flattened body and enlarged pectoral and pelvic fins give it a ray-like appearance. There is a band of enlarged thorns running along the middle of its back. It is gray or brown in color, with scattered small dark spots. This species reaches 1.2–1.5 m (3.9–4.9 ft) in length.

<span class="mw-page-title-main">Peppered catshark</span> Species of shark

The peppered catshark is a common but little-known species of catshark, part of the family Scyliorhinidae, inhabiting depths of 130–1,326 m (427–4,350 ft) in the northern Gulf of California. It is found on or near the ocean floor, and conducts seasonal migrations, spending winter in deeper water. Reaching a length of 37 cm (15 in), this species has a slender grayish body with a fine covering of black dots. On the dorsal edge of its caudal fin is a prominent crest of enlarged dermal denticles. It is oviparous, with the reproductive period probably lasting from May to September. The International Union for Conservation of Nature (IUCN) has listed the peppered catshark under Least Concern, as it faces no significant threats from human activity.

<span class="mw-page-title-main">Sawback angelshark</span> Species of shark

The sawback angelshark is an angelshark of the family Squatinidae It is one of rarest species of sharks known to date, and one of the three species of angelsharks that inhabits the Mediterranean. The Sawback angelshark lives in sandy and muddy bottoms of the ocean at depths of 30-500m.

<span class="mw-page-title-main">Chilean angelshark</span> Species of shark

The Chilean angelshark is an angelshark of the family Squatinidae found in the subtropical waters of Chile, that grows up to 1.03 metres in length. The holotype is lost. The species was redescribed and a neotype designated in 2024. Reproduction is ovoviviparous.

<span class="mw-page-title-main">Australian angelshark</span> Species of shark

The Australian angelshark is a species of angelshark, family Squatinidae, found in the subtropical waters of southern Australia from Western Australia to New South Wales between latitudes 18°S and 41°S, at depths down to 255 m (840 ft). Its length is up to 1.52 m (5 ft). Reproduction is ovoviviparous, with up to 20 pups in a litter.

<span class="mw-page-title-main">Pacific angelshark</span> Species of shark

The Pacific angelshark is a species of angelshark, family Squatinidae, found in the eastern Pacific Ocean from Alaska to the Gulf of California, and from Ecuador to Chile, although those in the Gulf of California and southeastern Pacific may in fact be separate species. The Pacific angelshark inhabits shallow, coastal waters on sandy flats, usually near rocky reefs, kelp forests, or other underwater features. This species resembles other angel sharks in appearance, with a flattened body and greatly enlarged pectoral and pelvic fins. Characteristic features of this shark include a pair of cone-shaped barbels on its snout, angular pectoral fins, and a brown or gray dorsal coloration with many small dark markings. It attains a maximum length of 1.5 m (4.9 ft).

<span class="mw-page-title-main">Taiwan angelshark</span> Species of shark

The Taiwan angelshark is an angelshark in the family Squatinidae. The Taiwan angelshark is one of four species of Squatina in the waters around Taiwan and Japan. It is a demersal, ray-like shark that grows to 1–2 meters in length.

<span class="mw-page-title-main">Japanese angelshark</span> Species of shark

The Japanese angelshark is a species of angelshark, family Squatinidae, found in the northwestern Pacific Ocean off China, Japan, and Korea. It is a bottom-dwelling shark found in sandy habitats down to 300 m (980 ft) deep. This species has the flattened shape with wing-like pectoral and pelvic fins typical of its family, and grows to 1.5 m (4.9 ft) or more in length. Its two dorsal fins are placed behind the pelvic fins, and a row of large thorns occurs along its dorsal midline. Its upper surface is cryptically patterned, with numerous squarish dark spots on a brown background.

<span class="mw-page-title-main">Ocellated angelshark</span> Species of shark

The ocellated angelshark is an angelshark of the family Squatinidae found only from the Taiwan Straits in the western Pacific between latitudes 28 and 22°N and in northern Malaysia. Its length is up to 63 cm.

<span class="mw-page-title-main">Clouded angelshark</span> Species of shark

The clouded angelshark is an angelshark of the family Squatinidae found in the northwest Pacific from the southeastern Sea of Japan to Taiwan between latitudes 47° N and 22° N. Its length is up to 1.63 m.

<span class="mw-page-title-main">Smoothback angelshark</span> Species of shark

The smoothback angelshark is an angelshark of the family Squatinidae found in the eastern Atlantic and Mediterranean.

<span class="mw-page-title-main">Indonesian angelshark</span> Species of shark

The Indonesian angelshark is a rare species of angelshark, family Squatinidae, known only from a few specimens collected from fish landing sites in southern Indonesia. It is thought to inhabit the deep waters of the continental slope. Reaching at least 1.34 m (4.4 ft) long, this species has a flattened, ray-like shape and a well-developed tail and caudal fin. It is characterized by the absences of fringes on its nasal barbels and thorns down the midline of its back, as well as by its relatively plain grayish-brown dorsal coloration with dark saddles beneath the dorsal fin bases and a black leading margin on the underside of the pectoral fins. The International Union for Conservation of Nature (IUCN) has classified it as Critically Endangered due to significant fishing pressure.

The Philippines angelshark is a species of angelshark, family Squatinidae, known only from a 33 cm (13 in) long immature female caught in the Philippines, where it is the only known representative of its family. It has a flattened body and head with greatly expanded pectoral and pelvic fins, and is greenish above with brown spots. Identifying traits of this species include the spiracles, which are more widely spaced than the eyes and bear papillae on the posterior inner rims, and the relative positions of the two dorsal fins. Additionally, S. caillieti lacks fringes on its barbels, enlarged thorns along the middle of its back, and ocelli ("eyespots") on its fins.

<span class="mw-page-title-main">Disparate angelshark</span> Species of shark

The disparate angelshark is a species of angelshark found along the East Coast of the United States and the Gulf of Mexico. It occurs at depths down to 1,290 m (4,230 ft) and reaches a length of 49 cm (19 in). Heteroptera in its name refers to the difference in size, shape and area of the two dorsal fins. Disparate angelsharks have the typical angel shark body form that is broadly flattened with large pectoral/pelvic fins and eyes and spiracles on the top of their heads. Their common and species name comes from them having dorsal fins of very different sizes, shapes, and areas compared to other angel sharks.

<span class="mw-page-title-main">Vari's angelshark</span> Species of angelshark

Vari's angelshark is an angelshark in the family Squatinidae found in Southwestern Atlantic, specifically Brazil. It lives in the continental slope between latitudes 11° and 22°S, at the depths of 195–666 m (640–2,185 ft).

References

  1. 1 2 3 4 5 6 7 8 9 Morey, G.; Barker, J.; Hood, A.; Gordon, C.; Bartolí, A.; Meyers, E.K.M.; Ellis, J.; Sharp, R.; Jimenez-Alvarado, D.; Pollom, R. (2019). "Squatina squatina". IUCN Red List of Threatened Species . 2019: e.T39332A117498371. doi: 10.2305/IUCN.UK.2019-1.RLTS.T39332A117498371.en . Retrieved 13 November 2021.
  2. 1 2 3 4 5 6 Compagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Rome: Food and Agricultural Organization. pp. 150–151. ISBN   978-92-5-101384-7.
  3. ↑ Smith, H.M. (1907). North Carolina Geological and Economic Survey Volume II: The Fishes of North Carolina. E.M. Uzzell & Co., State Printers and Binders. pp. 37–38.
  4. 1 2 3 Froese, Rainer; Pauly, Daniel (eds.) (2009). "Squatina squatina" in FishBase . July 2009 version.
  5. ↑ Stelbrink, B.; T. von Rintelen; G. Cliff & J. Kriwet (2010). "Molecular systematics and global phylogeography of angel sharks (genus Squatina)". Molecular Phylogenetics and Evolution. 54 (2): 395–404. doi:10.1016/j.ympev.2009.07.029. PMID   19647086.
  6. 1 2 Lythgoe, J. & G. Lythgoe (1991). Fishes of the Sea: The North Atlantic and Mediterranean. Blandford Press. pp. 29–30. ISBN   978-0-262-12162-0.
  7. ↑ Compagno, L.J.V.; M. Dando & S. Fowler (2005). Sharks of the World. Princeton University Press. p. 146. ISBN   978-0-691-12072-0.
  8. 1 2 3 Murch, A. Common Angel Shark Information and Pictures. Elasmodiver.com. Retrieved on July 8, 2009.
  9. ↑ MacKenzie, K. (1990). "Cestode parasites as biological tags for mackerel (Scomber scombrus L.) in the Northeast Atlantic". Journal du Conseil International pour l'Exploration de la Mer. 46 (2): 155–166. doi:10.1093/icesjms/46.2.155.
  10. ↑ Kearn, G.C. (1962). "Breathing movements in Entobdella soleae (Trematoda, Monogenea) from the skin of the common sole" (PDF). Journal of the Marine Biological Association of the United Kingdom. 42 (1): 93–104. Bibcode:1962JMBUK..42...93K. doi:10.1017/S0025315400004471. S2CID   54077382.
  11. ↑ Henderson, A.C. & J. Dunne (2001). "The distribution of the microbothriid shark parasite Leptocotyle minor on its host, the lesser-spotted dogfish Scyliorhinus canicula". Biology and Environment: Proceedings of the Royal Irish Academy. 101B (3): 251–253.
  12. ↑ Ramdane, Z. & J. Trilles (2008). "Cymothoidae and Aegidae (Crustacea, Isopoda) from Algeria". Acta Parasitologica. 53 (2): 173–178. doi: 10.2478/s11686-008-0033-8 . S2CID   35127351.
  13. ↑ Capapé, C.; J.P. Quignard & J. Mellinger (1990). "Reproduction and development of two angel sharks, Squatina squatina and S. oculata (Pisces: Squatinidae), off Tunisian coasts: semi-delayed vitellogenesis, lack of egg capsules, and lecithotrophy". Journal of Fish Biology. 37 (3): 347–356. Bibcode:1990JFBio..37..347C. doi:10.1111/j.1095-8649.1990.tb05865.x.
  14. ↑ Lineaweaver, T.H. (III) & R.H. Backus (1970). The Natural History of Sharks . J.B. Lippincott. p.  178.
  15. ↑ Dalby, A. (2003). Food in the Ancient World from A to Z. Routledge. p. 120. ISBN   978-0-415-23259-3.
  16. ↑ Matron, S.; D. Olson & A. Sens (1999). Matro of Pitane and the Tradition of Epic Parody in the Fourth Century BCE: Text, Translation, and Commentary. Oxford University Press US. p. 108. ISBN   978-0-7885-0615-4.
  17. ↑ Davidson, A. (2004). North Atlantic Seafood: A Comprehensive Guide with Recipes (3rd ed.). Ten Speed Press. p. 171. ISBN   978-1-58008-450-5.
  18. ↑ Kelleher, L. (December 23, 2013). "Only 12 left of Irish shark species that's 4m years old". Irish Examiner. Retrieved December 30, 2013.
  19. ↑ Narváez, K., F. Osaer, B. Goldthorpe, E. Vera and R. Haroun. (2007). Sighting of the angel shark Squatina squatina by Davy Jones Diving in the island of Gran Canaria. Davy Jones Diving. Retrieved on July 8, 2009.
  20. ↑ Ruddock, J. (Feb. 21, 2008) The Wildlife and Countryside Act 1981 (Variation of Schedule 5) (England) Order 2008 No. 431. Office of Public Sector Information. Retrieved on July 7, 2009.
  21. ↑ The making of the Wildlife and Countryside Act 1981 (Variation of Schedule 5) (Wales) Order 2008. Welsh Assembly Government. Retrieved on July 24, 2009.
  22. ↑ "Rare shark born in Deep Sea World in UK first". BBC News. November 18, 2011. Retrieved December 5, 2011.
  23. ↑ Briggs, Helen (25 January 2019). "Rare angel sharks found living off Wales". BBC News. Retrieved 25 January 2019.

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