Lipid and carotenoid quantification in leatherback turtle eggs: insights into reproductive success and conservation

The role of egg nutrients in the embryonic development success of threatened marine reptiles remains relatively unexplored from a conservation perspective. This study assesses lipid and carotenoid profiles in leatherback turtle Dermochelys coriacea eggs, which have the lowest hatching success among marine turtles. Correlations between inter-individual nutrient concentrations and reproductive parameters were also investigated. Samples from 47 eggs in 18 clutches from different females were chemically examined at Playa Pacuare Reserve, Costa Rica. Carotenoid concentrations were consistently low compared to other marine turtle species and positively correlated with the proportion of eggs with yolk within each clutch. Larger females deposited eggs with higher proportions of saturated fatty acids, which correlated directly with nest fertility and hatchling size. Our results on the concentrations of lipid nutrients (carotenoids and fatty acids) and their measured correlations with persistent organic pollutants (POPs) and reproductive success indicators reveal that these factors may have a much more significant relevance to reproductive success than previously recognized and deserve further attention from conservation biologists. Integrating egg yolk nutrients into the reproductive scenario of marine turtles opens several avenues for further research. Given the spatial variability of the effects of increasing global pollution and the apparent relationship between nutrients and persistent organic pollutants in egg yolk, studies focusing on improving incubation success should carefully monitor the balance and reproductive effects of these compounds.