Influência do manejo de ninhos de Podocnemis unifilis sobre o desenvolvimento de embriões no Lago Erepecu, REBIO- Trombetas (PA)

Abstract

In Erepecu Lake in the Biological Reserve Rio Trombetas (REBIO) in Pará, Brazil they have been using a management technique for Podocnemis unifilis which involves the transfer of natural nests to a single beach and holding the newly hatched turtles (headstarting) for about 30 days, before they are released into the lake. It is known that environmental variables such as height and distance of the nest in relation to the water level of the lake, plant cover, soil type, and incubation temperature can considerably affect the energetic content of the hatchlings and consequentially their survivorship chances after release. The objective of this study is to verify the influence of this management on the nests of P. unifilis in regard to the development of the embryos. The environmental variables mentioned below were measured for 42 nests in situ and after the transfer. Female P. unifilis invest about 4,69 ± 0,44 kcal/g of dry weight in their eggs. The caloric content of 1-30 day old hatchlings did not differ significantly in the beach where the eggs were trasnsferred, only the differences between the size of the sand particles in situ and the incubation beach were significant (p<0,05). The carapace length of the hatchlings was influenced for incubation temperature, soil moisture and plant cover. The results of this study indicate that, apparently, the management techniques used in the REBIO- Trombetas have no effect on the development of the embryos, however the data are not sufficient to support the hypothesis that the ex situ tecniques are benficial to the hatchlings in the long run.