Angular rough shark (Oxynotus centrina)

Description

Angular rough shark fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Angular rough shark description

A rare and little-known species, the angular rough shark (Oxynotus centrina) is suitably named for its pointed head and fins, and the rough teeth-like scales, known as ‘denticles’, which cover its body. The angular rough shark has a broad, flattened head, a short, blunt nose and two tall, sail-like dorsal fins ^{(3) (4)}.

The upperparts of the angular rough shark’s body are a marbled pattern of greyish-brown, with dark blotches on the head and sides. A number of lighter streaks decorate the head ^{(3) (4)}.

The angular rough shark has extremely large, oval or crescent-shaped spiracles, situated beside the eyes ^{(3) (4) (5)}.

French

Centrine Commune.

Spanish

Cerdo Marino.

Size

Male length: 64 cm ⁽²⁾

Female length: 78 cm ⁽²⁾

Angular rough shark biology

The diet of the angular rough shark is believed to consist of polychaete worms, crustaceans and molluscs ⁽⁴⁾, which it apparently feeds on using a suction mechanism ⁽⁶⁾. It typically moves by gliding along the seabed, frequently pausing to hover over the sandy or muddy surface ⁽⁷⁾.

The angular rough shark is an ovoviviparous species, with females producing litters of 10 to 12 pups each year. These pups measure 21 to 24 centimetres at birth ⁽⁴⁾. Female angular rough sharks become sexually mature when they reach around 65 centimetres in length, while males reach maturity at around 60 centimetres ⁽²⁾.

Angular rough shark range

The angular rough shark occurs in the eastern Atlantic Ocean and the Mediterranean Sea ⁽¹⁾. It may also occur off the coast of East Africa, near Mozambique, but this is debated ⁽³⁾.

Angular rough shark habitat

The angular rough shark is typically found close to the sea bed at depths between 60 and 660 metres. It is most commonly associated with muddy or coralline substrates ^{(1) (4)}.

Angular rough shark status

The angular rough shark is classified as Vulnerable (VU) on the IUCN Red List ⁽¹⁾.

Angular rough shark threats

Deep water fisheries in the Mediterranean and the northeast Atlantic are threatening the angular rough shark, which, although not specifically targeted by fishermen, is often caught as bycatch ^{(1) (3)}. When captured, the shark may be discarded ⁽⁴⁾, or used for oil, food for fish farms or food for humans ⁽³⁾.

Bottom trawling in the Mediterranean Sea has become more efficient over the last 50 years, resulting in the angular rough shark now being extremely rare. In the northeast Atlantic, little information is available on angular rough shark numbers, but as deepwater fisheries have expanded in both range and effort, it is likely that the angular rough shark has declined in this region too ⁽¹⁾.

Angular rough shark conservation

There are currently no management plans in place for the conservation of the angular rough shark ⁽⁴⁾, but a number of conservation measures have been recommended.

Bycatch of the angular rough shark needs to be monitored, to gain a better picture of its population numbers and the impact fisheries are having on this species. A more thorough knowledge of the angular rough shark’s ecology and distribution will also help inform any future conservation measures ⁽¹⁾.

Ultimately, sustainable management plans that ensure the conservation of all sharks in the Mediterranean need to be developed and implemented ⁽¹⁾. As more than 40 percent of shark and ray species in the Mediterranean are now considered to be threatened with extinction, the need for conservation action is considered by many to be urgent ⁽⁸⁾.  

Find out more

Discover more about shark conservation:

• Shark Trust:
  http://www.sharktrust.org/
• Shark Alliance:
  http://www.sharkalliance.org/
• Bite-Back – Shark and Marine Conservation:
  http://www.bite-back.com/

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Glossary

Bycatch

In the fishing industry, the part of the catch made up of non-target species.

Coralline

Derived or formed from coral.

Crustaceans

A diverse group of animals with jointed limbs and a hard external skeleton, characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.

Dorsal fins

The unpaired fins found on the back of the body of fish.

Molluscs

A diverse group of invertebrates, mainly marine, that have one or all of the following; a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.

Ovoviviparous

Ovovivipary is a method of reproduction whereby the egg shell is weakly formed and young hatch inside the female; they are nourished by their yolk sac and then ‘born’ live.

Polychaete worms

Polychaeta means ‘many bristled’; this class of worms are segmented and bear many ‘chaetae’ (bristles).

Spiracles

Openings which enable water to be pumped through the gills whilst the shark is resting.

References

1. IUCN Red List (October, 2010)
   http://www.iucnredlist.org/
2. Capape, C., Seck, A.A. and Quignard, J.P. (1999) Observations on the reproductive biology of the angular rough shark, Oxynotus centrina (Oxynotidae). Cybium, 23(3): 259-271.
3. Compagno, L.J.V. (1984) FAO Species Catalogue: Sharks of the World. Part 1 - Hexanchiformes to Lamniformes. Food and Agriculture Organization of the United Nations, Rome. Available at:
   http://www.fao.org/docrep/009/ad122e/ad122e00.htm
4. Shark Trust (2010) An Illustrated Compendium of Sharks, Skates, Rays and Chimaera. Chapter 1: The British Isles and Northeast Atlantic. Part 2: Sharks. The Shark Trust, Devon, UK.
5. Grigg, G.C. (1970) Use of the first gill slits for water intake in a shark. Journal of Experimental Biology, 52: 569-574.
6. Capape, C. (2008) Diet of the angular rough shark Oxynotus centrina (Chondrichthyes: Oxynotidae) off the Languedocian coast (southern France, north-western Mediterranean). Vie et Milieu-Life and Environment, 58: 57-61.
7. Kabasakal, H. (2009) Observations on a rare shark, Oxynotus centrina (Chondrichthyes: Oxynotidae), in the Sea of Marmara (north-western Turkey). Pan American Journal Aquatic Sciences, 4: 609-612.
8. Eccleston, P. (2007) Med sharks and rays threatened by extinction. The Telegraph, 16 November (Online). Available at:
   http://www.telegraph.co.uk/earth/earthnews/3314652/Med-sharks-and-rays-threatened-by-extinction.html