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Amblyraja georgiana 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Rajiformes Rajidae

Scientific Name: Amblyraja georgiana (Norman, 1938)
Common Name(s):
English Antarctic Starry Skate
Synonym(s):
Raja georgiana Norman, 1938
Taxonomic Notes: A species of Amblyraja, previously identified as A. cf. georgiana, occurs around the Falkland/Malvinas Islands and appears to be most closely related to A. frerichsi. It does however, differ from A. frerichsi in a number of characteristics and may be identical to an undescribed Amblyraja from South Georgia (as specified in Endicott et al. 2002) (J. Pompert pers. comm.). Amblyraja georgiana from the Ross Sea appears to have low-level genetic differentiation from South Atlantic A. georgiana, and further work is required to determine whether the Ross Sea A. georgiana is distinct (M. Francis pers. comm.). Taxonomic resolution of this issue is ongoing. Endicott et al. (2002) found A. georgiana to have a restricted depth range around South Georgia, with an unknown rajid species comprising the rest of the deep water captures. Although A. georgiana is reported to have been regularly caught around Antarctica in deep water, findings by Endicott et al. (2002) suggest that complications and difficulties in identification of Antarctic rajids may lead to misidentification.

Assessment Information [top]

Red List Category & Criteria: Data Deficient ver 3.1
Year Published: 2009
Date Assessed: 2004-09-06
Annotations:
Needs updating
Assessor(s): Endicott, M. R. & Kyne, P.M.
Reviewer(s): Francis, M., Valenti, S.V. & Bates, H. (Shark Red List Authority)
Justification:
The Antarctic Starry Skate (Amblyraja georgiana) is a medium-sized skate (to 100 cm TL) found in the Southern Ocean. Although its distribution is possibly circum-Antarctic, recent genetic analyses suggest that this species is comprised of several genetically-distinct stocks. The species is vulnerable to bycatch in trawl and longline fisheries, although recent depth restrictions on fisheries in South Georgia protect a portion of the population. The lack of data on catches and population trends together with taxonomic uncertainty warrants a Data Deficient assessment at present. Given that this species may have limiting life-history characteristics like other large deepwater skates, further information is required on the impact of fisheries. Resolution of the taxonomic issues is also a priority.

Geographic Range [top]

Range Description:Reported as possibly circum-Antarctic in the Southern Ocean, although taxonomic uncertainties preclude an accurate assessment of distribution at this time. Reports from the Falkland/Malvinas Islands in the southwest Atlantic appear to be erroneous and are based on another Amblyraja species (J. Pompert pers. comm.).
Countries occurrence:
Native:
Antarctica
FAO Marine Fishing Areas:
Native:
Atlantic – Antarctic; Indian Ocean – Antarctic; Pacific – Antarctic
Additional data:
Lower depth limit (metres):800
Upper depth limit (metres):150
Range Map:Click here to open the map viewer and explore range.

Population [top]

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

Habitat and Ecology [top]

Habitat and Ecology:A. georgiana occurs on the upper to mid continental slope at depths of 150-800 m (Endicott et al. 2000, 2002; Endicott 2003). Endicott et al. (2002) also indicate that where A. georgiana is commonly caught, peak captures are found to occur at depths of around 400 m. The species reaches a maximum size of 101 cm total length (TL) and size at birth is 16-18 cm TL (Endicott et al. 2002, Endicott 2003). Size at maturity is estimated at 84 cm TL, but this estimate is based on joint male and female data sets (Endicott et al. 2002). Like other skates, this species is oviparous, but little else is known of its biology. Reproduction takes place in both winter and late summer (Endicott 2003, Endicott et al. 2002). A. georgiana's feeding ecology appears to be mainly opportunistic, ranging from small teleosts, to polycheates and crustaceans (Endicott, MRAG, unpublished data).
Systems:Marine

Use and Trade [top]

Use and Trade: Unknown

Threats [top]

Major Threat(s): A. georgiana is taken by commercial longline and trawl fisheries operating within its range and it is caught as bycatch and discarded within the fishery around South Georgia (Endicott and Agnew 2003). The severity of bycatch mortality off South Georgia is thought to be low, due to restrictions on fishing depths implemented in 2004. Until the implementation of these measures A. georgiana was caught frequently. Further information on catches and population trends is required.

Conservation Actions [top]

Conservation Actions: The South Georgia Government prohibited fishing in waters <500 m deep within the toothfish longline fishery in 2004.

CCAMLR recommend that whenever possible during longlining operations, live skates and rays should be cut from the line while still in the water, and vessels should be encouraged to develop methods to minimise bycatch of skates SC-CCAMLR (2002).

Classifications [top]


In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Conservation sites identified:Yes, over entire range
In-Place Species Management
In-Place Education
5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.4. Unintentional effects: (large scale) [harvest]
♦ timing:Ongoing    
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

1. Research -> 1.1. Taxonomy
1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
1. Research -> 1.5. Threats
3. Monitoring -> 3.1. Population trends

Bibliography [top]

Endicott, M. 2003. Skate captures during the 2003 South Georgia Research Survey. CCAMLR, Hobart, Australia.

Endicott, M., Agnew, D.J. and Nolan, C.P. 2000. Examination of the skate by-catch from around South Georgia from one vessel in the 2000 longline toothfish season. CCAMLR, Hobart, Australia.

Endicott, M., Compagno, L.J.V. and Agnew, D.J. 2002. Identification of Amblyraja species in the longline fishery in Sub-area 48.3. CCAMLR, Hobart, Australia.

IUCN. 2009. IUCN Red List of Threatened Species (ver. 2009.2). Available at: www.iucnredlist.org. (Accessed: 3 November 2009).

SC-CAMLR. 2002. Report of the Twenty-first Meeting of the Scientific Committee (SC-CAMLR-XXI). CCAMLR, Hobart, Australia.

Stehmann, M. and B├╝rkel, D.L. 1990.. Rajidae. In: In: O. Gon and P.C. Heemstra. J.L.B. (eds), (eds), Fishes of the Southern Ocean., pp. 462 pp.. Smith Institute of Ichthyology,, Grahamstown.


Citation: Endicott, M. R. & Kyne, P.M. 2009. Amblyraja georgiana. The IUCN Red List of Threatened Species 2009: e.T161490A5435813. . Downloaded on 23 April 2018.
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