|Scientific Name:||Atlantoraja cyclophora (Regan, 1903)|
|Red List Category & Criteria:||Vulnerable A3bd+4bd ver 3.1|
|Assessor(s):||Massa, A., Hozbor, N. & Vooren, C.M.|
|Reviewer(s):||Kyne, P.M. & Cavanagh, R.D. (Shark Red List Authority)|
A small (to ~70 cm total length) softnose skate endemic to southern Brazil, Uruguay and Argentina on the continental shelf to 300 m. Demand for skates is increasing on an international scale, resulting in growing fishing pressure on skate species along the coastal and continental shelf waters of Argentina and Uruguay. In these countries, Atlantoraja cyclophora is mainly taken as bycatch in fisheries for coastal demersal species (multi-species fisheries), however, since 2000, specific targeting of skates has occurred. A. cyclophora is known to have been landed in Argentina since 1994, however landing statistics are generally unavailable as all species of batoids are recorded as "unidentified rays and skates". Trawl fishing in this species' habitat is intense and in the coastal waters of Buenos Aires Province, Argentina and Uruguay (34° to 41°S), biomass estimates fell more than 50% from 1994 to 1999 (Hozbor and Massa unpublished data). Despite a lack of data on this species from Brazil, fishing pressure is also intense in these waters, and while apparently still quite common in Brazil at present, given the estimated decline of 50% biomass in part of its range, together with increasing fishing pressure and demand for skates, an overall assessment of Vulnerable is considered appropriate and precautionary. Continued monitoring, species-specific catch data and improved management are urgently needed.
|Range Description:||Endemic to southern Brazil, Uruguay and Argentina on the continental shelf to 300 m.|
Native:Argentina; Brazil; Uruguay
|FAO Marine Fishing Areas:|
Atlantic – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Biomass in the coastal waters of Buenos Aires Province, Argentina and Uruguay (34° to 41°S) was estimated as 697 tons for Spring 1999 (Massa et al. 2000). It remains apparently quite common in its usual depth range in Brazil (Vooren, pers. obs).|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||Found on the continental shelf between shallow waters (50 m in Brazil) and 300 m depth (Vooren 1997, Cousseau and Perrotta 2000). Maximum size in Argentina 68.2 cm TL (male) and 69.5 cm TL (female), in Brazil 64 cm TL (male) and 65 cm TL (female) (Cousseau and Perrotta 2000, Oddone 2003). In Brazil, size at first maturity is 47 cm TL (male) and 53 cm TL (female). Female breeding occurs all year round and is not synchronized throughout the population (Oddone 2003). Eggs and small juveniles are not caught in the Brazilian trawl fishery and are evidently not vulnerable to the types of trawl used (Oddone 2003).
The diet of this species consists of crustaceans (stiletto shrimp, amphipods, crabs), polychaete worms and teleost fish (mainly Engraulis anchoita).
Many aspects of the life-history of A. cyclophora that are important for management (e.g., fecundity and natural mortality) are still unknown.
Trawl fishing along the distribution and in the habitat of this species is intense, while demand for skates is increasing in the international market. In the coastal and continental shelf waters of Argentina and Uruguay this has resulted in rising fishing pressure on all skate species. A. cyclophora is taken mainly as bycatch in fisheries for coastal demersal species (multi-species fisheries) and in Argentina the species has been known to be landed since 1994. Since 2000, however, one vessel has been specifically targeting skates. For these fishing activities, species-specific landing statistics are generally unavailable as all species of batoids are recorded as "unidentified rays and skates". In the coastal waters of Buenos Aires Province, Argentina and Uruguay (34°-41°S), biomass estimates fell more than 50% from 1994 to 1999 (Hozbor and Massa unpublished data). In an observer program of the Puerto Quequen coastal benthic trawl fishery in Buenos Aires Province, Argentina, A. cyclophora was found to constitute 3.7% by number and 4.0% by mass of the batoids captured, and occurred in 34.2% of trawls (Tamini et al. 2006). Within this fishery, A. cyclophora is either retained and landed for commercial purposes or discarded, depending on size. The majority of specimens captured were immature (Tamini et al. 2006).
Fishing pressure is also known to be intense across the species' range in southern Brazil, where demersal trawl fisheries operate and skates are landed as part of multi-species fisheries. Species-specific data are required from southern Brazil.
|Conservation Actions:||No conservation measures exist in Brazil. In Argentina, the only management strategy for skates is an annual total catch for skates distributed in the coastal waters of Buenos Aires. For 2003 this was 4,000 t. Continued monitoring and species-specific catch data are needed across the species' range.|
|Citation:||Massa, A., Hozbor, N. & Vooren, C.M. 2006. Atlantoraja cyclophora. The IUCN Red List of Threatened Species 2006: e.T61398A12462475.Downloaded on 14 December 2017.|