Brown catshark
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| Brown catshark | ||||||||||||||||
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| Apristurus brunneus (Gilbert, 1892) |
Brown catsharks, Apristurus brunneus, (originally Catulus brunneus) are commonly found in the Pacific ocean, ranging from the northern Pacific waters off the coast of British Columbia and down to the Baja California peninsula in Mexico. It is believed that they may live as far south as Ecuador and Peru. Brown Catsharks are deepwater sharks that live on the outer continental shelf and the upper slope. They have been known to live in depths ranging from 30 to 650 m and live on the bottom, usually in muddy or sandy areas.
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[edit] Physical description
Brown catsharks have long, slender bodies with broad, bell-shaped snouts. They are dark brown with light colored markings on the posterior margins of their fins. Their bodies are soft and flabby, with a weak skin that can easily be harmed. Brown catsharks have two dorsal fins that are the same size and do not have spines. The first dorsal fin originates to the front of the pelvic fin and the second dorsal fin is located in front of the anal fins insertion. They typically reach a maximum size of 68 cm in total length, however they average between 30 and 60 cm.
[edit] Behavior
Very little is known about the behavior of brown catsharks, however they are believed to be solitary, nocturnal creatures. It is believed that they are migratory, however they live most of the year near the edge of the continental shelf.
Communication specific to brown catsharks is unknown. However, as with most other sharks, including other members of the family Scyliorhinidae, it is believed that they have a well-developed sense of smell, and that they are electroreceptive, which allows them to detect electricity emitted by other animals, and may also allow them to detect magnetic fields, which aides in navigation.
[edit] Food habits and predation
Brown catsharks feed on many bottom-dwelling species, including small true shrimps, euphausiids, squids, and small fishes. It is unknown whether brown catsharks are important predators within their ecosystem.
It is believed that brown catsharks are preyed on by larger sharks and fish species, however these species are currently unknown.
[edit] Reproduction
Reproduction in brown catsharks is oviparous with a single egg at a time per oviduct. Egg cases are usually about 5 cm long and 2.5 cm wide. The egg cases are transparent and have long tendrils that are probably used to attach them to hard structures. The incubation period is possibly a year. In Canadian waters females carry egg cases from February to August, however, the carrying time for warmer waters is unknown.
[edit] Conservation status and economic impact
Brown catsharks are not listed as endangered on the IUCN Red List, the U.S. Federal List, or the CITES list. They are not known to be a vulnerable or threatened species. They are, however, listed on the IUCN list as needing to be reclassified.
The only known negative impact that brown catsharks have on humans is the frequent bycatch of deepwater trawlers, which while not economically significant can cause damage to nets as well as time lost in removing the bycatch from the viable catch.
[edit] References
- Huveneers & Duffy (2004). Apristurus brunneus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006. Database entry includes justification for why this species is listed as data deficient
- Apristurus brunneus (TSN 159988). Integrated Taxonomic Information System. Retrieved on 18 April 2006.
- 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 2 - Carcharhiniformes.. FAO Fish. Synop. 125(4/2):251-655.
- Huveneers, C. & Duffy, C. 2004. Apristurus brunneus. In: IUCN 2004. 2004 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 06 April 2006.
- Nakaya, K. and Sato, K. 1999. Species grouping within the genus Apristurus (Elasmobranchii: Scyliorhinidae). In: B. Séret & J.-Y. Sire (ed.) Proceedings of the 5th Indo-Pacific Fish Conference (Nouméa, 3-8 November 1997). Paris, Society Francaise d’Ichthyologie et Instutue de Recherches pour le Development: 307 – 320.
- Shark Foundation. 2006. "Brown catshark (Apristurus brunneus)" (On-line). Accessed April 6, 2006 at http://www.shark.ch/Database/Search/species.html?sh_id=1189
[edit] External links
- IUCN Red List Classification
- "Apristurus brunneus". FishBase. Ed. Ranier Froese and Daniel Pauly. February 2006 version. N.p.: FishBase, 2006.
