Population size, reproductive ecology and heavy metal levels in eggshells of the Nile soft-shell turtle (Trionyx triunguis) around thermal Lake Kükürtlü (Sulphurous), Mugla-Turkey

Abstract

The distribution of adult turtles and the environmental conditions influencing hatching success and nesting of the Nile soft-shell turtle (Trionyx triunguis) around Lake Sulphurous in Mugla, Turkey were investigated. A total of 77 emergences of nesting females were recorded with only 22 (28.57 %) of them resulting in nests and their incubation periods have been studied. The adult emergences occurred from May to mid July. The hatching success of these nests was 69%, 20% of the eggs were predated and 11% were recorded as infertile and dead in shell embryos. The incubation periods lasted between 55-56 days. The heavy metal concentrations of the eggshells were analysed and the mean concentrations in µg g-1 were recorded as 26.95 for Fe, 6.35 for Ni, 2.607 for Cr, 0.98 for Cu and 0.19 for Cd. The concentrations of Pb in eggshells were below the detection limit. The population sizes as well as preventive measures to protect this critically endangered species to survive were discussed.