Literaturdatenbank
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Moreira, G. M. (2003). Population dynamics of the endangered turtle phrynops hogei in the carangola river, brazil. Abstracts ASIH Meeting 2003.
Added by: Admin (14 Aug 2008 20:36:25 UTC) |
| Resource type: Journal Article BibTeX citation key: Moreira2003 View all bibliographic details  |
Categories: General Keywords: Chelidae, Habitat = habitat, Mesoclemmys, Mesoclemmys hogei, Phrynops, Schildkröten = turtles + tortoises, Südamerika = South America Creators: Moreira Collection: Abstracts ASIH Meeting 2003 |
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| Abstract |
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Phrynops hogei is a small freshwater turtle endemic to the Paraíba do Sul River Basin. The turtle has been listed as endangered in Brazil since 1989. I studied a population of P. hogei in a section of the Carangola River in Minas Gerais. Turtles were captured in unbaited fyke nets, measured, marked, and released in the area of capture. I captured 71 turtles, 36 (50.70%) males, 31(43.67%) females, and 4 (5.63%) juveniles. Males were smaller than females (mean 1.92 kg, SD 0.69) vs. (mean 2.17 kg, SD 0.84). Recaptures were found within 900 m of first capture. The capture rate was highly seasonal, with the sex ratio varying between seasons. The population studied had a small proportion of juveniles compared to adults, suggesting that the decline in population size could be due to recruitment. The most probable cause of lack of recruitment is predation of eggs and hatchlings, but also reduced fecundity due to senility or pollution must also be considered. Based on the observation that the majority of the turtles captured are near the maximum size observed for this species, it appears as though the population is composed primarily of adults near the point of senescence. However nothing is known about the longevity or fecundity of this species at advanced ages. The high incidence of captures during the dry season corresponded to movements associated with the nesting season, as more females were captured than males, and gravid female were captured only at this time of the year. I began this study under the premise that the lack of systematic collecting was at fault for not documenting the fact that populations of this species were more widely dispersed and in higher numbers than reported, this was not the case, Phrynops hogei is the most endangered species of turtle in Brazil.
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