Oviparous (Ref. 50449). Eggs have horn-like projections on the shell (Ref. 205).
Limited distribution, recorded from northern South America in the west central Atlantic, from Venezuela, Trinidad and Tobago, Guyana and Suriname (McEachran and Carvalho 2002).
Western Central Atlantic: northern coast of Colombia, Venezuela, Trinidad and Tobago.
Maximum size: 500 mm WD
50.0 cm WD (male/unsexed; (Ref. 5217))
Habitat and Ecology
Habitat and Ecology
Found at depths of 37 to 174 m along the continental shelf. Maximum known size is 51 cm TL (McEachran and Carvalho 2002) and males mature by at least 50 cm TL. Disc width has been estimated at 70% of total length (McEachran and Carvalho 2002). Oviparous like other skates, but nothing else known of its biology or ecology. Systems
demersal; marine; depth range 30 - 180 m (Ref. 5217)
Depth range based on 2 specimens in 1 taxon.
Water temperature and chemistry ranges based on 1 sample.
Depth range (m): 141.5 - 174
Temperature range (°C): 17.651 - 17.651
Nitrate (umol/L): 13.261 - 13.261
Salinity (PPS): 36.061 - 36.061
Oxygen (ml/l): 3.342 - 3.342
Phosphate (umol/l): 0.971 - 0.971
Silicate (umol/l): 5.894 - 5.894
Depth range (m): 141.5 - 174
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Life History and Behavior
Oviparous, paired eggs are laid. Embryos feed solely on yolk (Ref. 50449).
IUCN Red List Assessment
Red List Category Year Assessed
Near Threatened Red List Criteria Version
Valenti, S.V. Reviewer/s
Kyne, P.M. & Gibson, C.G. (Shark Red List Authority) Contributor/s Justification
A little known skate with a relatively restricted distribution on the continental shelf from Venezuela to Suriname in the Western Central Atlantic. This species is found at depths of 37 to 174 m and reaches a maximum size of 51 cm TL. Little is known of the biology and ecology. Demersal trawling is intense off Venezuela, with a commercial fleet of shrimp trawlers operating on the continental shelf and Trinidad and Tobago, where overall bycatch levels have declined from 13,712 t in 1987 to 4,099 t in 2001. The species composition of this catch has not been examined. Although no specific data are available, given the species' relatively limited geographic range, intense trawl fisheries operating throughout much of its range and high levels of bycatch, this species is assigned a precautionary assessment of Near Threatened. Bycatch levels of this species need to be defined and monitored in order to make a full assessment of this species' status and the assessment may need to be revisited in the near term.
Unknown. Population Trend
Trawling began off northeastern Venezuela in the late 1960s (Mendoza and Marcano 1994). The main trawling fleet predominantly operates on the continental shelf surrounding the Isla de Margarita and north of the Estado Sucre (Mendoza and Marcano 1994). Demersal trawl effort has increased in both effort and efficiency; 150 vessels were permitted to operate out of the port by the Ministry for Fisheries and Agriculture (DGSPAMAC) in 1990, each with between 250 to 650 Horse Power (hp), giving a total nominal horse power of 37,500 to 97,500hp (Mendoza and Marcano 1994). By 2003 the commercial trawl fleet had increased to about 400 shrimp trawlers operating on the continental shelf (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.
Intensive trawling also occurs in Trinidad and Tobago's waters (Mohammed and 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 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).
Trawl fisheries are also known to operate off Guyana and Suriname, however details on the current effort and depths fished are not available at the present time.
Although there no specific data are available, this species is most probably taken as bycatch in these trawl fisheries, operating throughout much of its range. Given the relatively limited distribution of the species, and trawl fisheries operating throughout its range it is suspected current fishing pressure is unsustainable for R. cervigoni.
Near Threatened (NT)
Surveys of abundance and distribution are required, as are details on fisheries operating within the species' area of occurrence. Bycatch levels in these fisheries need to be defined and monitored.