Alometria reprodutiva da tartaruga-da-amazônia Podocnemis expansa (Schweigger, 1812), tracajá Podocnemis unifilis (Troschel, 1848) e iaçá Podocnemis sextuberculata (Cornalia, 1849) na praia do Jamanduá, médio rio Purus no município de Canutama, Sudoeste do Amazonas

Abstract

Turtles play an important role in the northern region as a protein source and for their ecological role in nature as key species maintaining ecological balance eggs and young turtles are a source of protein for several other groups (mammals, birds, reptiles and fishes). Turtles are also important seed and fruit dispersers in floodplains and igapó floodplain forests after ingesting dead organic matter. The current research covered a study of reproductive allometry of tartaruga-da-Amazônia species (Podocnemis expansa) and evaluated the characteristics of nests, eggs and hatchlings (Podocnemis unifilis) and iaçás (Podocnemis sextuberculata) in the Jamanduá district, in the municipality of Canutama (Amazonas state) in 2019. The data were analyzed in two excursions: August 2019 (nesting period) and November 2019 (hatching period), with the purpose of monitoring the reproductive period of the species in study. The females were captured at night after laying the eggs by using the turning method and biometrics were performed (length and rectilinear width of the carapace - CRL and LRC; rectilinear length and width of plastron - CRC and LRC; height - ALT) weighing and marking with holes in the carapace and metallic platelets, being subsequently released. In order to estimate the number of nests of each species, in the morning, the beach was visited to count, register and mark the nests. 33 turtle nests were opened, 5 nests of natural tracajás, 11 nests of the transplant and 5 of iaçás for counting, biometrical measurements and sample weighing of the eggs. At the time of hatching, 60 days later, 33 turtle nests were opened, 5 nests of natural tracajás and 11 nests of transplantion and 5 of iaçás for counting and biometrics and sample weighing of the eggs. At the time of hatching, 60 days later, 33 nests of turtles, 5 of natural tracajás and 11 of transplantation were opened, and 5 of iaçás for counting live chicks, estimation of hatching rate and sample biometrics (CRC, LRC, CRP, LRP and ALT) and weighing the puppies. Descriptive statistics and histograms were made from the registered variables of females, eggs and chicks. The relationships between the variables measured in the females and their respective eggs and chicks were made through Pearson's correlation and linear regression analysis. The captured females had an average weight of 34.55 kg ± 5.57 (range 23 - 48 kg) and an average carapace length of 71.16 ± 4.23 cm (range 52.5-79.0 cm). The average number of eggs per nest of P. expansa was of 120 ± 16 eggs / nest (maximum: 150; minimum: 81 eggs). The nests had an average depth of 45.39 ± 11.70 cm (range 25 - 72 cm). The chicks had an average of 25.75 g and 51.26 mm of rectilinear length with a medium carapace, and we found only the following linear regressions between nest width and number of live chicks and incubation days; female plastron width and number of unviable eggs and hatching rate, showing that the larger the female the greater the amount of eggs, the larger the nest, the longer the incubation time and the greater the number of non-viable eggs resulting in a lower hatching rate. There were no significant linear relationships between the size of the females and young turtles