Individual nest site preference of green turtle, Chelonia mydas, on Mak Kepit beach and its relation with hatching emergence success

Abstract

We investigated 160 individual in-situ nests of 24 female green turtles which laid their eggs in 4 to 10 clutches during the 2002 nesting season in order to determine whether and how nest site preferences vary among individuals. We also quantified the impact of this maternal behavior on reproductive success by evaluating offspring hatching and emergence success. We found that there was a significant repeatability of female preferences to nest under canopies at 70.6% (113 nests) compared to grasses/creeper areas at 22.5% (36 nests) and bare sand areas at 6.9% or 11 nests. The density of nests under canopies was the highest at one nest per 4.2 ㎡ (1/4.2 ㎡) followed by grasses and bare sand areas at 1/12.8 ㎡ and 1/36.6 ㎡ respectively. Most turtles preferred to lay their eggs on the right side of their first clutch and closer to the forest line. Hatching success was higher for nests situated within bare sand areas at 92.1% compared to 88.7% within grasses areas and 88.2% under canopies. The emergence success was also higher for nests situated within bare sand at 88.2% compared to 81.2% under canopies and 79.9% within grasses areas. However the percentages of undeveloped eggs were higher for nests situated within grasses areas compared to under canopies and bare sand areas at 4.7%, 2.6% and 1.5% respectively.