Demographic and health parameters of green sea turtles Chelonia mydas foraging in the Gulf of Carpentaria, Australia

Abstract

It is becoming increasingly apparent that the development of management initiatives for sea turtles depends on the collection of biological data at all life stages. Substantial gaps include a lack of data on both the population’s demographic structure and reference values for biochemical parameters that can be used to assess the health and condition of sea turtle populations. Here we pre- sent comparative data on population demographics and biochemical blood parameters for green sea turtles Chelonia mydas in their foraging grounds of the Sir Edward Pellew (SEP) Islands in the Gulf of Carpentaria, Australia. Turtles within the adult size range for Australian green turtles comprised 54% of turtles caught. Of the turtles with curved carapace lengths (CCL) greater than 85 cm, 41 were adult males, one was an adult female, and 15 could not be confidently sexed. Continued surveys are needed to distinguish between the potential causes underlying this male-biased sex ratio and the dif- ference between the sex ratio we found and those previously published for the population. Based on biochemical analysis of blood, green turtles in the SEP foraging grounds appeared to be healthy. However, mean levels of glucose and magnesium were generally lower than the ranges observed in other studies of clinically healthy green turtles. Additionally, glucose levels were lower in turtles with CCLs of over 85 cm.