Estrutura populacional, razão sexual e abundância de Podocnemis sextuberculata (Testudines, Podocnemididae) na Reserva de Desenvolvimento Sustentável Mamirauá, Amazonas, Brasil

We studied turtles in the focal area of the Reserva de Desenvolvimento Sustentável Mamirauá from September 1996 through August 1998. The reserve is located in the western part of the Brazilian Amazon, between the Japurá, Solimões, and Auti-Paraná rivers, near the city of Tefé, in the state of Amazonas. In this study the population structure, sex ratio and abundance of Podocnemis sextuberculata were investigated. We intensively studied the population of turtles in the Jarauá river basin in order to determine population structure. We sampled turtles in different sectors in the focal area of the reserve for one month each year during July and August of 1997 and 1998. We captured the turtles using flag gill nets and trammel nets. The type of net and the size of the nets used influenced the size of the turtles captured. The nets used by the local fishermen were sexually selective in the capture of the turtles. Sevent-two percent of the P. sextuberculata captured were adults; 13% juveniles and 14.7% subadults. During the second year of the study we found a lower density of turtles in the five areas wich we sampled each years. The sex ratio of captured P. sextuberculata was 1.87 males per female