Abstract

GONZALEZ-ZARATE, ADRIANA; MONTENEGRO, OLGA; CASTANO-MORA, OLGA VICTORIA  and  VARGAS-RAMIREZ, MARIO. Abundance, Population Structure and Conservation of Podocnemis lewyana (Podocnemididae) at the Prado River, Colombia. Acta biol.Colomb. [online]. 2014, vol.19, n.3, pp.351-361. ISSN 0120-548X.  https://doi.org/10.15446/abc.v19n3.41565.

Along the Prado River, at southeast of Colombia, there is a population of Podocnemis lewyana, an endemic and endangered river turtle. Relative abundance, population structure and conservation threats were determined using field data obtained in 2007 and 2009. Relative abundance was estimated by turtle catch per unit of time, which was used to compare between the two sampling years. Additionally, turtles per kilometer were counted in 2009 alone, to compare with other populations distributed in the north of the country. The population structure was determined by the frequency of individuals of several size classes and sex ratio of captured animals. Sexual dimorphism was examined in adult animals by morphometry. One hundred and ten turtles were captured in 2007 and 72 in 2009. The relative abundance of individuals observed was an averaged of 54.46 sightings/ km representing the most abundant population of the country so far. The population's structure was characterized by a higher frequency of individuals of 21-30 cm maximum straight carapace length SCL and absence of individuals of less than 10 cm SCL or greater than 40 cm SCL. Sex ratio was 2.52:1 for 2007 and 2.75:1 for 2009, being higher for females. The main identified threats to the population of P. lewyana at Prado River were (i) alterations of habitat, (ii) changes in the natural flow of the river, (iii) the use of inappropriate fishing arts and (iv) probable interruption of migrations. Prado River is hereby proposed as priority area for further research and conservation of Podocnemis lewyana in the upper Magdalena river basin.

Keywords : Colombia; dams; endemic endangered turtle; populations; Prado River; Upper Magdalena river basin.

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