|Scientific Name:||Narcine brasiliensis|
|Species Authority:||(Olfers, 1831)|
|Taxonomic Notes:||Recent revisions have subdivided the previously wide-ranging Narcine brasiliensis into Narcine bancroftii (Griffith, 1834) which is widely distributed from North Carolina, USA, through parts of the Gulf of Mexico, the Caribbean Sea, the Greater Antilles, the Lesser Antilles and the northern coast of South America to northern Brazil and Narcine brasiliensis (Olfers, 1831) which is endemic to the Southwest Atlantic in Brazil, Uruguay and Argentina (Carvalho 1999).
One additional species of Narcine, either an undescribed form or an overlooked description (e.g., N. nigra Duméril, 1852), occurs in northeastern Brazil.
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||Rosa, R.S. & Furtado, M.|
|Reviewer(s):||Kyne, P.M., Fowler, S.L. & Valenti, S.V. (Shark Red List Authority)|
Narcine brasiliensis is a shallow water coastal endemic of the Southwest Atlantic from Brazil, Uruguay and Argentina, found on soft substrates usually at depths less than 40 m. References to the species from the Northwest and North Central Atlantic refer to the closely related Narcine bancroftii. There is still some uncertainty with regard to the northern limit of the distribution of N. brasiliensis, and the taxonomic status and distribution of Narcine species in northeastern Brazil. This species is taken as bycatch in coastal trawl and beach seine fisheries, however no quantitative data are available on captures. Coastal fishing pressure is intense in the Southwest Atlantic and declines of 98% since 1972 have been documented for Narcine bancroftii in the northern Gulf of Mexico. There is some anecdotal evidence of declines in captures of Narcine spp. in artisanal beach seines during the past decade in Paraíba, northeastern Brazil, however it is uncertain whether these are N. brasiliensis or N. bancroftii. The lack of available quantitative data precludes an accurate assessment of the status of N. brasiliensis at this time and it is assessed as Data Deficient. Research is required to resolve taxonomic issues, better define distribution, and determine population size and life-history characteristics of this species. Future monitoring of artisanal fisheries taking it as bycatch should also be a priority and this assessment should be re-visited once data are available.
|Range Description:||Confusion concerning the geographic range of N. brasiliensis stems from the species being previously considered as a wide-ranging Western Atlantic species from North Carolina, USA to Argentina. Taxonomic revision (Carvalho 1999) has defined N. bancroftii as occurring from North Carolina south to northern Brazil and N. brasiliensis from Brazil, Uruguay and Argentina. In spite of this, Gomes and Carvalho (2003) still cite N. brasiliensis as occurring from North Carolina to Argentina. At present, there remains some uncertainty as to the exact range of the two species in Brazil, particularly off northeastern Brazil (M. Carvalho pers. comm). References to Narcine from the northern states of Amapa, Pará and Maranhão are N. bancroftii, while references from Bahia, São Paulo, Paraná and Rio Grande do Sul are N. brasiliensis. Narcine brasiliensis is also known from Paraíba and Pernambuco states (R. Rosa pers. obs.), however, it is uncertain to which species records from other parts of northeastern Brazil (including Ceará State) belong, but may represent records of N. brasiliensis (M. Carvalho pers. comm).|
Native:Argentina; Brazil; Uruguay
|FAO Marine Fishing Areas:|
Atlantic – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Apparently uncommon in Argentina, the southern extent of its range (A. Massa pers. comm.).|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Little information available as previously reported data are for Narcine bancroftii (where reported from the Western Central Atlantic and from northern Brazil). A shallow water coastal species, benthic on soft substrates usually at depths less than 40 m. Reproduction is aplacental viviparous but nothing else is known of the biology.|
Electric rays are sluggish swimmers, with small home ranges, highly localized within an area and concentrating in surf zones adjacent to barrier beaches and on offshore sand bars in warm months and moving offshore in winter (Rudloe 1989), making them susceptible to localized population depletion. Narcine brasiliensis is captured as bycatch in coastal trawl and beach seine fisheries. No quantitative data are available on the capture of this species in Brazil and it does not appear to be utilised for food and is discarded, but survivorship rates are unknown. Captures of Narcine spp. in artisanal beach seines appear to have declined during the past decade in Paraíba, northeastern Brazil (R. Rosa pers. obs.), however it is uncertain whether these are N. brasiliensis or N. bancroftii.
Skate and ray landings in the artisanal fishery of Rio Grande do Sul, southern Brazil have declined since the early 1950s (Vooren et al. 2005). This species is still recorded in Rio Grande do Sul, southern Brazil and a scientific trawl survey at 7 to 20 m depth between Torres and Chuí in February 2005 recorded N. brasiliensis at a CPUE of 6.48 number/hour (juveniles and adults) (Vooren et al. 2005), although the proportion of juveniles and adults is unknown. Further information is required on temporal variations in abundance (Vooren et al. 2005).
Coastal fishing pressure is also known to be intense in Argentina. Batoids are an important resource in most demersal trawl fisheries in Argentina (Tamini et al. 2006). A coastal multispecies demersal trawl fishery operates at Quequén, in which bycatch of batoids fluctuates seasonally between 44.5% and 67.5% of total capture (Tamini et al. 2006). This species was not reported in a recent study of the bycatch of this fishery (Tamini et al. 2006), and a lack of historical information prevents a comparison of temporal trends. No information is available on the population of this species in Argentina, where it is uncommon (A. Massa pers. comm). Declines of 98% (95% Confidence Intervals 0.5 to 5%) since 1972 have been observed for Narcine bancroftii in the northern Gulf of Mexico (Shepherd and Myers 2005), as well as similar rates of decline in US coastal waters, between Florida and North Carolina. Narcine brasiliensis has a more limited distribution than N. bancroftii, however there is no data to make an accurate assessment of its status at this time.
Pollution and human disturbance in the coastal zone may also be detrimental to N. brasiliensis' habitat, although no specific information is available.
|Conservation Actions:||Research to resolve taxonomic issues and determine distribution, population size and life history is required. Monitoring of artisanal fisheries in which the species is taken as bycatch is also required.|
|Citation:||Rosa, R.S. & Furtado, M. 2007. Narcine brasiliensis. The IUCN Red List of Threatened Species 2007: e.T63157A12602819.Downloaded on 23 June 2017.|