Angel Shark ( Squatina squatina )

/ / Fish

Description

Although Angel sharks resemble rays morphologically, they are actually a species of shark (1). They can reach lengths of up to 244cm and weights of 40kg. The body is flat with large pectoral fins and a skin colour ranging between grey, red and brown with black and white dots (2). Young angel sharks tend to have more markings than the adults (1) and it is thought that the colouration is used as a form of camouflage (2). Near the nostrils there are whisker-like barbels which are used to sense prey (3). It eyes are large and round, allowing the Angel shark to be an efficient predator (4).

Due to its benthic lifestyle, the Angel shark is especially exposed to benthic trawls, set nets and bottom longlines which operate throughout its distribution (5). Much of its decline has been attributed to bycatch from these fishing methods.

Behaviour

The Angel shark is nocturnal and only leaves the seabed at night (1). It spends its day buried on the seabed with only its eyes showing (1), and can stay in the same spot for long periods of time (6). It stays hidden until its prey is in striking range and then strikes up its head and protrudes its jaw over the prey (2).

Life cycle

The lifespan of the Angel shark is unknown, as is its age at sexual maturation. However, it is known that females reach maturity at 128 to 169 cm, and males at 80 to 132 cm (5). Angel sharks are ovoviviparous, with gestation lasting 8 to 10 months and producing between 7 and 25 pups approximately 30cm in length (3). Birth occurs between December and February in the Mediterranean (5).

Habitat

Mud or sandy bottom-dwellers in the intertidal or subtidal zones of temperate regions down to 150m (2).

Distribution

Mediterranean Sea and Atlantic Ocean; however, its distribution is reduced compared to its historic range, as a result of severe population depletion (5).

Migration

The Angel shark displays seasonal migration patterns, moving to colder northern regions during the summer (2).

Food

Molluscs, crustaceans and bony fish, including flatfish and skates.

Conservation Status

IUCN Red List Status: Critically Endangered (Assessed 2006) (5)

UNCLOS

UNFSA

Bern Convention Appendix III (7)

Barcelona Convention Annex III

References

Description written by Jo Pollett (2009)

(1)   ARKive, 2006. Angel Shark – Squatina squatina – Information – ARKive – facts and status. [Online] Available at: http://www.arkive.org/angel-shark/squatina-squatina/info.html [Accessed 19 August 2009].

(2)   Moran, M., 2009. Squatina squatina Fact Sheet. [Online] Available at: http://www.sharktrust.org/do_download.asp?did=32883 [Accessed 19 August 2009].

(3)   Compagno, L.J.V., Fowler, S. and Dando, M. 2005. Sharks of the World. London:Harper Collins.

(4)   Compagno, L.J.V. (1984) FAO Species Catalogue. Vol. 4: Sharks of the World. An annotated and illustrated catalogue of shark species known to date. Part 1: Hexanchiformes to Lamniformes. Food and Agriculture Organization of the United Nations, Rome.

(5)   Morey, G., Serena, F., Mancusi, C., Fowler, S.L., Dipper, F. & Ellis, J. 2006. Squatina squatina. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1. <www.iucnredlist.org>. Downloaded on 19 August 2009.

(6)   Elasmodiver, 2009. Common Angel Shark Information and Pictures of Squatina squatina. [Online] Available at: http://www.elasmodiver.com/CommonAngelShark.htm [Accessed 19 August 2009].

(7)   Europe, C.o., 2002. Convention on the conservation of European wildlife and natural habitats: Bern Convention. [Online] Available at: http://conventions.coe.int/Treaty/FR/Treaties/Html/104-3.htm [Accessed 19 August 2009].