Proposal of a non-lethal visual census method to estimate freshwater stingray abundance
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...
| Autor Principal: | Morales-Betancourt, Mónica Andrea; Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Street 28a #15-09 Bogotá, Colombia |
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| Otros Autores: | Lasso-Alcalá, Carlos Andrés; Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Street 28a #15-09 Bogotá, Colombia |
| Formato: | info:eu-repo/semantics/article |
| Idioma: | eng |
| Publicado: |
Pontificia Universidad Javeriana
2016
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| Materias: | |
| Acceso en línea: |
http://revistas.javeriana.edu.co/index.php/scientarium/article/view/15364 |
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| Sumario: |
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. |
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