The Nile Softshell Turtle (Trionyx triunguis): Nest Parameters and A New Nesting Site

Abstract

There are no studies carried out on nest parameters of the Nile softshell turtle (Trionyx triunguis) in Turkey except for few studies on the Western Mediterranean coast of Turkey. In this study, 12 nests of the Nile softshell turtle were examined in terms of nest parameters during 2016 and 2017 nesting seasons on Belek, Göksu, and Burnaz beaches located on the Central and Eastern Mediterranean coast of Turkey. Nesting period started in May (17%) but intensified in June (83%). The distance of nests to the shore, depth of nests, clutch temperature, clutch size, and hatching success in the nests were recorded and calculated. Among three beaches, the lowest hatching success rate was on Göksu Beach (0.18 ± 0.26), whereas the values were similar on Belek (0.75 ± 0.22) and Burnaz (0.72 ± 0.36) beaches. Although clutch temperatures were measured in a range (29.5–33.0 °C) that is optimal for embryo development, most of the eggs inside nests were dead at the late embryonic period (5.1 ± 9.6) which was followed by early (1.8 ± 3.1) and middle stage embryos (0.3 ± 0,6). The highest number of unfertilized eggs was recorded on Burnaz Beach (14.5 ± 19.1) and the lowest was on Belek Beach (1.0 ± 1.5). Regarding the relationship between the nest parameters, it was detected that only the clutch temperature has a significant relationship with the clutch size. In this study, a new nesting site for the softshell Nile turtle on Burnaz Beach was discovered and nest parameters in this species were indicated on three beaches.