Salinity of incubation media influences embryonic development of a freshwater turtle

Abstract

Variations in water potential have marked effects on aspects of embryological development in reptiles. Therefore variation in the salinity of the incubation environment is likely to have significant consequences on the early life stage. The combination of an extended incubation period, coupled with the real threat of soil salinisation within their range makes Chelodina expansa an ideal model to assess the influence of salinity on turtle embryology. We quantified the influence of salt on the development of C. expansa hatchlings in four substrate treatments varying in salinity. Embryos incubated in higher salinities had 39 % less survival than those incubated in substrates with freshwater. Hatchlings that emerged from eggs in saline treatments were smaller with higher concentrations of plasma sodium, chloride, urea, and potassium. The physiological effects of salinity mirror those of turtles incubated in drier media with low water potential. Salinisation of river banks has the potential to reduce hatching success and fitness of nesting reptiles.