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MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps13500

Low male production at the world’s largest green turtle rookery

D. T. Booth*, A. Dunstan, I. Bell, R. Reina, J. Tedeschi

*Corresponding author:

ABSTRACT: Because all sea turtle hatchlings have their sex determined by incubation temperature, low temperatures producing mainly males and high temperatures producing mainly females, sea turtle populations worldwide are threatened by feminisation of hatchlings due to increases in global temperature. Data obtained by laparoscopic sexing of immature individuals captured from a major feeding ground indicates that there has been little recruitment of males into the northern Great Barrier Reef (nGBR) green turtle (Chelonia mydas) population, one of the largest sea turtle populations in the world, over the several decades. We measured nest temperatures at Raine Island, the most important nesting site for this nGBR population over two nesting seasons and predicted that almost all nests produced all female hatchlings. The few nests that produced some male hatchlings were constructed at the very end of the nesting season, and these nests had the lowest hatching success. Taking into account monthly variations in nest construction, hatching success and hatchling sex ratio, we estimate that over an entire nesting season only 0.7% of hatchlings produced are male. Hence, we conclude that the nGBR population of green turtles has likely recruited very few males in recent years.