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Angelshark

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This article is about the genus. For the species, see angelshark.

Angel sharks
Temporal range: 161–0 Ma[1] Oxfordian to Present
Japanese angelshark, Squatina japonica
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Chondrichthyes
Subclass:
Elasmobranchii
Order:
Squatiniformes

Family:
Squatinidae

Bonaparte, 1838
Genus:
Squatina

Type species
Squalus squatina
Linnaeus, 1758
Squatina squatina, usually known simply as the angelshark, is the type species for all angelsharks
Ornate angelshark, Squatina tergocellata
Australian angelshark, Squatina australis

An angel shark is a shark in the genus Squatina, which are unusual in having flattened bodies and broad pectoral fins that give them a strong resemblance to rays. Twenty-three species are known to exist in the genus, which is the only one in its family, Squatinidae, and order Squatiniformes. They occur worldwide in temperate and tropical seas. Most species inhabit shallow temperate or tropical seas, but one species inhabits deeper water, down to 1,300 metres (4,300 ft).[2]

Appearance and biology

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, Squatina japonica, known to reach 2 m.[3] 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.[2] They are ovoviviparous, producing litters of up to 13 pups.

Behavior

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.[4] If they are left alone, they will not attack.[citation needed]

Commercial value

Prior to the late 1970s, the Pacific Angel Shark was considered a "junk fish".[5] It was a by-product of commercial Gillnetting with no commercial appeal and was used only for crab bait. In 1977, Michael Wagner, a fish processor in Santa Barbara, California, in cooperation with local commercial fisherman, developed the market for angel sharks.[5] The annual take of angel shark in 1977 was an estimated 147 kilograms.[5] By 1985, the annual take of angel shark on the central California coast had increased to more than 454 metric tons or an estimated 90,000 sharks.[5] The population declined dramatically and is now regulated.

In April 2008 the UK Government afforded the angel shark full protection under the Wildlife and Countryside Act. Once considered abundant in the Atlantic ocean, the angel was classified as "critically endangered" in 2010.[6]

Species

See also

References

  1. ^ Bourdon, J. (2009). Genera from the Fossil Record: Squatina. The Life and Times of Long Dead Sharks. Retrieved on July 8, 2009.
  2. ^ a b Stevens, J. & Last, P.R. (1998). Paxton, J.R. & Eschmeyer, W.N. (ed.). Encyclopedia of Fishes. San Diego: Academic Press. pp. 64–65. ISBN 0-12-547665-5.{{cite book}}: CS1 maint: multiple names: authors list (link)
  3. ^ Froese, Rainer, and Daniel Pauly, eds. (2009). "Squatinidae" in FishBase. January 2009 version.
  4. ^ Best, Cathleen. "Florida Museum of Natural History." PACIFIC ANGEL SHARK. (Date accessed 06/23/2010) <http://www.flmnh.ufl.edu/fish/gallery/descript/pacificangelshark/pacificangelshark.html>.
  5. ^ a b c d Richards, John B. "Developing a localized fishery: the Pacific angel shark." Sharks: an inquiry into biology, behavior, fisheries, and use. S. Cook (ed.). EM 8330 (1987): 147-160.
  6. ^ Fowler, Susan (2010). "Background Document for Angel shark Squatina squatina" (PDF). German Federal Agency for Nature Conservation. The Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR). Retrieved 24 October 2013.
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