Amblyraja taaf 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Rajiformes Rajidae

Scientific Name: Amblyraja taaf (Meissner, 1987)
Common Name(s):
English Whiteleg Skate
Raja taaf Meissner, 1987

Assessment Information [top]

Red List Category & Criteria: Data Deficient ver 3.1
Year Published: 2009
Date Assessed: 2008-12-01
Assessor(s): Endicott, M.
Reviewer(s): Notarbartolo di Sciara, G. & Valenti, S.V. (Shark Red List Authority)
The Whiteleg Skate (Amblyraja taaf) is a little-known skate occurring in the Indian Antarctic Ocean, just south of the Crozet and Kerguelen Islands and far south of South Africa and Madagascar. South African records may prove to be vagrants. Found at depths of 150-600 m, though probably it occurs deeper. This species is taken as utilised bycatch by longline and trawl fisheries targeting Patagonian Toothfish (Dissostichus eleginoides) in the Antarctic and southern Indian Ocean. Actual bycatch levels are likely to be much greater than actually reported, as a result of illegal and unmonitored fishing. Insufficient information is available on population trends, biology and fisheries throughout this species range to assess it beyond Data Deficient at present. However, the species may have limiting life-history characteristics, similar to other deepwater skates, making it vulnerable to population depletion, and it is recommended that this assessment be revisited in the near-term.

Geographic Range [top]

Range Description:Antarctic and Southern Indian Ocean: known from just south of the Crozet and Kerguelen Islands and well south of South Africa and Madagascar (Stehmann and B├╝rkel 1990, Compagno and Ebert 2007).

Southeast Atlantic Ocean: the South African records of A. taaf may prove to be of strays from its known range in sub-Antarctic seas (Compagno and Ebert 2007).
Countries occurrence:
Antarctica; French Southern Territories (Crozet Is., Kerguelen)
FAO Marine Fishing Areas:
Atlantic – southeast; Indian Ocean – Antarctic
Additional data:
Lower depth limit (metres):600
Upper depth limit (metres):150
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Population size is unknown.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Thought to be widespread in the Indian Antarctic ocean at depths of 150 to 600 m, though may be found at greater depths (Stehmann and Burkel 1990). Dulvy and Reynolds (2002) give a minimum depth of 320 m and a maximum of 350 m, with a latitudinal range of two degrees. Maximum size is reportedly 90 cm total length (TL) and size at birth is about 17 cm TL (Stehmann and Burkel 1990). Diet appears to be wide ranging from polycheates and crustaceans, to teleosts (Meissner 1987).

Amblyraja taaf is reported to display sexual dimorphism (Meissner 1987), with males in general being larger than the females. Fecundity is unknown for this species.

Threats [top]

Major Threat(s): This species is taken as utilised bycatch by longline and trawl fisheries targeting Patagonian Toothfish (Dissostichus eleginoides) in the Antarctic and Southern Indian Ocean. This species, along with grenadiers Macrourus carinatus, forms the bulk of bycatch of the Patagonian Toothfish fishery in the Crozet Islands EEZ. Bycatch of Rajids (Amblyraja taaf) in this fishery reported to Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) ranged from nothing in 1998/1999, increasing to 95 to 91 t in 2002-2004 and to 163 t in 2005/2006 (CCAMLR 2006).

Actual bycatch levels are likely much greater though as a result of illegal, unreported and unregulated (IUU) fishing for Patagonian toothfish throughout the area. Most IUU fishing is thought to have occurred in the Indian Ocean sector around Crozet, Heard, Kerguelen and Prince Edward Islands (Lack and Sant 2001). Increased surveillance within the EEZ of these states in recent years means that IUU fishing now occurs mainly outside the EEZ.

This species probably has limiting life-history characteristics similar to other deepwater skates, making it vulnerable to population depletion. Current levels of exploitation may therefore be unsustainable.

Conservation Actions [top]

Conservation Actions: None in place.

The CCAMLR Working Group recommend that, where possible, all rajids should be cut from the line while still in the water, except on the request of observers, and that areas with high bycatch rates should be avoided by Patagonian Toothfish fisheries.

Information is required to better define the distribution and the impact of fisheries across the species' entire range.

Citation: Endicott, M. 2009. Amblyraja taaf. The IUCN Red List of Threatened Species 2009: e.T161392A5413351. . Downloaded on 16 October 2018.
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