Gurgesiella dorsalifera

Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_onStatus_en_offStatus_cr_offStatus_ew_offStatus_ex_off

Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES RAJIFORMES RAJIDAE

Scientific Name: Gurgesiella dorsalifera
Species Authority: McEachran & Compagno, 1980
Common Name(s):
English Onefin Skate

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(v) ver 3.1
Year Published: 2004
Date Assessed: 2004-04-30
Assessor(s): Rincon, G.
Reviewer(s): Musick, J.A., Kyne, P.M., Cavanagh, R.D. & Fowler, S.L. (Shark Red List Authority)
Justification:
A small, poorly known endemic skate, known from localised areas off Santa Catarina State north to Rio de Janeiro State, Brazil, at depths of 400-800 m. It may also occur in deeper water. Often captured in large numbers as bycatch by the bottom otter trawl fleet in the area, this deepwater species is likely to have a low intrinsic rate of increase, and poor resilience to depletion. Increased fishing effort for squid in its limited extent of occurrence (estimated at 18,000 to 20,000 km²) is likely to affect the population. However, the squid fishery operates down to about 600 m, thus deeper water may provide some refuge for the species, although it does not appear to be abundant at the deeper end of its known bathymetrical range. The species is assessed as Vulnerable due to its restricted range, life history (as a deepwater species) and increasing fishing pressure (inferring a continuing reduction in the number of mature individuals). Its depth range and abundance in deeper water needs clarification.

Geographic Range [top]

Range Description:A Brazilian endemic locally known off Santa Catarina State north to Rio de Janeiro State, Brazil. At present most records are centered on the southern part of its range (Santa Catarina State), although this may be due to less fishing effort off Rio de Janeiro and São Paulo States were the continental slope is highly inclined.

Its extent of occurrence is estimated at 18,000 to 20,000 km².
Countries:
Native:
Brazil (Rio de Janeiro, Santa Catarina)
FAO Marine Fishing Areas:
Native:
Atlantic – southwest
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: The holotype was taken at 800 m (McEachran and Compagno 1980). Maximum size at least 42.4 cm total length (TL). Matures at 40.0 to 42.4 cm TL (males) and 36.5 cm TL (females). Oviparous, laying 4.5 cm eggs in September-October (spring). This species is a deepwater piscivorous skate and feeds mainly on juveniles (2 to 3 cm TL) of abrótea Urophycis brasiliensis at 400 to 600 m depth, but copepods and mysidaceans also make up part of its diet. Although the present information about its feeding aspect is restricted to two samples, the results are evidence of a trophic dependency of G. dorsalifera upon U. brasiliensis, which may be a point of concern given the high economic importance and heavy fishing of this teleost in the south of Brazil. It may occur deeper than 800 m and this needs clarification. Indications are that it is not abundant at the deeper end of its known depth range (400 to 800 m).
Systems: Marine

Threats [top]

Major Threat(s): A bycatch in deepwater fisheries. Increasing bottom trawl effort for squid in the only known area of its distribution is a matter of concern. This fishery operates down to about 600 m, so deeper water may provide a refuge for this species. Its main prey item, the teleost Urophycis brasiliensis, is heavily fished.

Conservation Actions [top]

Conservation Actions: None in effect or proposed. Bycatch mitigation is required. Closed areas may be required to protect this and other species in such areas of heavy, and increasing, fishing.

Bibliography [top]

IUCN. 2004. 2004 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 23 November 2004.

IUCN SSC Shark Specialist Group. Specialist Group website. Available at: http://www.iucnssg.org/.

McEachran, J.D. and Compagno, L.J.V. 1980. Results of the research cruises of FRV ?Walter Herwig" to South America. LVI: A new species of skate from the Southwestern Atlantic, Gurgesiella dorsalifera sp. nov. (Chondrichthyes, Rajoidei). Archiv. Fisherei Wissenchaft 31: 1-14.

Menni, R.C. and Stehmann, M.F.W. 2000. Distribution, environment and biology of batoid fishes off Argentina, Uruguay and Brazil, a review. Revista del Museo Argentino de Ciencias Naturales (Nueva Serie) 2(1): 69-109.

Séret, B. and Andreata, J.V. 1992. Deep-sea fishes collected during cruise MD-35 off Brazil. Cybium 16(1):81-100.


Citation: Rincon, G. 2004. Gurgesiella dorsalifera. In: The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 29 July 2014.
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