Nest site and nest content variables affect invertebrate infestation of marine turtle nests on Alata Beach, Mersin, Turkiye

Abstract

We studied nest site and nest content variables affecting invertebrate infestation in green turtle (Chelonia mydas; n = 180) and loggerhead turtle (Caretta caretta; n = 80) nests on Alata Beach, Mersin, Turkiye. Invertebrates were found in 46 (25.6 %) of the green turtle nests and 23 (28.8 %) of the loggerhead nests during three nesting seasons (2003, 2005, and 2007). The following variables were measured: distance between the nest and the nearest vegetation (DNV) or the water's edge (DWE), the number of unfertilized eggs (NUE), the number of empty eggshells (NEE), the duration of the incubation period (IP), and the hatching success rate (HSR). Both the related (NEE, HSR) and different variables (DWE and IP for green turtles; DNV and NUE for loggerheads) affected the severity of nest infestation in each species. According to the logistic regression analysis results, invertebrate presence is positively correlated to NUE, while a smaller DNV value can result in more invertebrate species inside and/or around loggerhead turtle nests. Invertebrate presence is also positively related to the nests' DWE, which decreases the HSR in green turtle nests. Green turtle nests on the Alata beach were deeper, closer to the vegetation, and further from the sea than the loggerhead turtle nests. Therefore, we believe that nest site and nest content variables affecting the presence of invertebrates differ between these two turtle species.