Published Feb 10, 2016


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Mónica Andrea Morales-Betancourt

Carlos Andrés Lasso-Alcalá



There is not a current method to estimate South American freshwater stingray’s abundance. Therefore we designed a census method and tested it in the field. It consists of making nocturnal surveys by boat in large rivers (>25m width) and floodplain lagoons of varying sizes, along transects of 100m x 10m (1000 m2). We applied this method in the Tomo River, a tributary of the Orinoco River in Colombia. 110 transects were surveyed in 200 runs. A total of 149 rays of four species were recorded: Potamotrygon motoro, Potamotrygon orbignyi, Potamotrygon schroederi and Paratrygon aiereba. P. motoro was the most abundant with a density of 0.31 individuals /1000 m2 (SD=0.5). This method gave optimal results when applied to habitats with high transparency and shallow depth (< 1m) since it permitted the identification of both adults and juveniles present.


density, Potamotrygonidae, Orinoco river basin, Colombia.

How to Cite
Morales-Betancourt, M. A., & Lasso-Alcalá, C. A. (2016). Proposal of a non-lethal visual census method to estimate freshwater stingray abundance. Universitas Scientiarum, 21(1), 23–32.
Biología marina, Oceanografía, Ecología / Marine biology, Oceanography, Ecology / Biologia marinha, Oceanografia, Ecolog