Assessing the relative importance of conservation measures applied on sea turtles: comparison of measures focusing on nesting success and hatching recruitment success

Conservation measures applied to sea turtle nesting sites have a beneficial effect on population trends and dynamics. Such measures aim to protect nesting females, increase nesting success (proportion of female emergences resulting in nests) and/or to improve hatching and hatchling emergence success. However, taking into account financial and time constrains it is important to identify those measures that have the most positive impact on the sea turtle population. The aim of this paper is to assess and compare the relative importance of the different factors that may influence the efficiency of conservation actions and to investigate which factors, those associated with decreased nesting success, or others leading to higher embryonic and hatchling mortality have a higher impact on overall hatchling recruitment. We developed a model that simulates the nesting activity of sea turtles. For model parameterization, we used data collected from nesting sites of the loggerhead sea turtles (Caretta caretta) in the Eastern Mediterranean. We conducted a series of simulations by simultaneously changing model input parameters. The results of the model illustrate that an increase in hatchling recruitment success (i.e., hatching and hatchling emergence success) would have a more positive effect on overall hatchling production than a similar in nesting success. Our analysis further suggests that changes in hatchling recruitment success even at a single site, could have an important impact on overall hatchling production of the rookery.