|Scientific Name:||Rhinobatos percellens|
|Species Authority:||(Walbaum, 1792)|
Raja percellens Walbaum, 1792
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor/s:||Casper, B.M. & Burgess, G.H.|
|Reviewer/s:||Kyne, P.M., Heupel, M. & Simpfendorfer, C. (Shark Red List Authority)|
The Southern Guitarfish (Rhinobatos percellens) has a wide distribution in the western Atlantic from the Caribbean to Brazil. Records of the species south to Mar del Plata (Argentina) apparently refer to the Brazilian Guitarfish (Rhinobatos horkelii). The Southern Guitarfish is found on the continental shelf from 0-110 m. Very little information is available and life history data are completely lacking. It is likely that this species is taken as bycatch in commercial and artisanal fisheries throughout its range and in some regions (i.e., parts of South America) inshore fishing is intense. It is also collected for the aquarium trade in Brazil. No species-specific data are available on population trends or catches for this species, however the closely-related Brazilian Guitarfish has suffered severe population depletion from overfishing in Brazil, as a result of intense inshore fishing pressure. This species is captured by similar, intense fisheries (shrimp trawls, otter trawls, beach seines and gillnets) operating on the northern coast of South America. Therefore it is inferred that Southern Guitarfish populations in this area have also decreased. The level of impact of fisheries on this species throughout the Caribbean Islands is uncertain. Trawl effort appears to be less in fisheries off Caribbean Islands (north of Trinidad and Tobago), although it may be taken by small-scale gillnet and beach seines there. This species is assessed as Near Threatened on the basis of inferred declines as a result of continuing high levels of exploitation (close to meeting the criteria for VUA2d+4d). Assessment of catches and the collection of species-specific data to determine population trends throughout its range is a priority and it may prove to have been more seriously depleted than estimated above.
|Range Description:||Western Atlantic: Jamaica, the Lesser Antilles (including the countries of St Kitts and Nevis, Antigua and Barbuda, Dominica, St Lucia, St Vincent and the Grenadines, Barbados and Grenada), Panama, Colombia, Venezuela, Trinidad and Tobago, Guyana, Suriname, French Guiana and Brazil (Menni and Stehmann 2000, McEachran and Carvalho 2002). Records of the species south to Mar del Plata (Argentina) apparently refer to R. horkelii and records from tropical waters of West Africa refer to R. albomaculatus (B. Séret pers. comm. 2008).|
Native:Antigua and Barbuda; Barbados; Brazil (Bahia, Pará); Dominica; Dominican Republic; French Guiana; Grenada; Guyana; Haiti; Jamaica; Martinique; Panama; Puerto Rico (Puerto Rico (main island)); Saint Kitts and Nevis; Saint Lucia; Saint Vincent and the Grenadines; Suriname; Trinidad and Tobago; Venezuela (Venezuela (mainland))
|FAO Marine Fishing Areas:||
Atlantic – southwest; Atlantic – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||No population or catch data are available for this species. However, the closely-related Rhinobatos horkelii has suffered severe population depletion (>80% between 1986 and 2001) from overfishing in Brazil (Lessa and Vooren 2007). This species is captured by similar, intense fisheries (shrimp trawls, otter trawls, beach seines and gillnets) operating on the northern coast of South America. Therefore it is inferred that R. percellens populations in this area have also decreased.|
|Habitat and Ecology:||Found on shallow, soft bottoms of the continental shelf at depths of 0?110 m. Reaches a maximum of 100 cm total length (TL) (McEachran and Carvalho 2002, Cervigón et al. 2002). Aplacental yolksac viviparous, but details of reproduction, or any other aspects of its biology are not known.|
It is likely that this species is taken as bycatch in commercial and artisanal fisheries throughout large areas of its range. In some regions of its distribution (e.g. parts of South America) inshore fishing is intense. This species is taken as a utilized bycatch of artisanal trawl and net fisheries in South America (Cervigón et al. 2002). Although the meat is considered of poor quality, it is often salted and consumed (Cervigón et al. 2002).
The continental shelf of Venezuela is thought to be intensively exploited. In Venezuela, demersal trawl effort has increased in both effort and efficiency during the past 50 years (Mendoza and Marcano 1994). Between 1990 and 2003 the commercial trawl fleet had increased from about 150 vessels to 400 shrimp trawlers operating on the continental shelf (Mendoza and Marcano 1994, Mendoza et al. 2003). In addition an artisanal fleet of 20,000 small vessels and about 1,000 medium and long-range vessels exists (Mendoza et al. 2003). The medium and long range fleet targets medium pelagics using pelagic longline and snappers and groupers (Lutjanus purpureus and Epinephelus spp.) using hand line and demersal longline (Mendoza et al. 2003). Overall temporal trends in total reported catches for Venezuela showed a steep increase in landings through the 1980s and 1990s, from about 150,000 t/year to over 350,000 t/year (Mendoza et al. 2003). Bycatch taken by shrimp trawlers off Venezuela was estimated at 96,000 tonnes annually and bycatch/shrimp ratios are typically between 5 and 15:1 in the region (Charlier 2000). Charlier (2000) indicates that although only a small part of this catch is utilized, several species have apparently disappeared from the bycatch. No information is available on the composition of catches at this time.
Intensive trawling also occurs in Trinidad and Tobago's waters (Mohammed and Chan A Shing 2003). Bycatch of the shrimp trawl fleet is considerably higher than the target catches. Total bycatch in these fisheries declined from 13,712 t in 1987 to 4,099 t in 2001 and the species composition of this bycatch has not yet been examined (Mohammed and Chan A Shing 2003). Data reporting is poor in these artisanal fisheries and official catches for some species, in some areas or time-periods, may under-represent true catches by 200-500% (Medoza et al. 2003). This species may also be vulnerable to the artisanal gillnet fishery that targets mackerel in coastal waters off Trinidad and Tobago and takes sharks as bycatch (Chan A Shing 1999).
In Guyana there is a partially directed gillnet fishery for sharks (~600 vessels) which captures both demersal and pelagic inshore species. This fishery operates in estuarine and shallow coastal waters (at depths of <40 m) (Chan A Shing 1999). About 100 industrial shrimp trawlers also take sharks and finfish as bycatch, but no details are available on the composition of the bycatch.
Inshore fishing pressure is also generally intense off Brazil, where significant declines in R. horkelii have been documented. This species is also collected for the commercial aquarium trade in Ceará state, Brazil.
Threats to this species throughout its range off Caribbean Islands (north of Trinidad and Tobago) are not well known. Inshore fisheries appear to comprise beach seines, balahoo seine and gillnets that target small coastal pelagics and traps and handlines that target reef, deep slope and shelf demersals (Zeller et al. 2003). Trammel net fisheries have targeted Caribbean spiny lobster (Panulirus argus) off Grenada since the 1980s and take a significant bycatch. The use of trammel nets is now prohibited in Grenada but still continues illegally (McConney and Baldeo 2007).
|Conservation Actions:||None currently in place. Research is required to provide data on take in fisheries, biology and ecology.|
|Citation:||Casper, B.M. & Burgess, G.H. 2009. Rhinobatos percellens. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 May 2013.|
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