81 5. Discussion We have investigated the connectivity pattern between two distinct loggerhead turtle nesting areas, located 150 km apart in the south of New Caledonia. The complementary use of three methodologies has provided a detailed knowledge over time of sex-specific variations of the nesting population’s space use with specific implications in terms of conservation strategy. High female fidelity to the nesting area Telemetric and CMR surveys conducted on reproductive females have highlighted an explicit fidelity pattern to their respective nesting areas, both within and between breeding seasons. This work adds to the large body of literature converging towards the same conclusion for various sea turtles species and regions around the world (Garofalo et al. 2009; Shamblin et al. 2011; Jensen et al. 2013). However, important variations in the spatial resolution of this breeding ground fidelity have been reported for loggerhead females, ranging from <2 km to >100 km within a single season (Tucker 2010). It was therefore necessary to clarify the spatial scale of this fidelity pattern between the two study areas. Satellite tracking revealed only limited movements from the beaches where tagging events occurred, with no shift recorded from one nesting area to the other. Considering the fairly low number of individuals that were tracked (n = 20), these results cannot exclude the possibility of infrequent intra-annual movements. However, the absence of shifts between the two nesting areas over 37 nesting cycles clearly supports a pattern of small-scale fidelity for reproductive females engaging in nesting either at the RP or at the GLS areas. Available tracking data did not allow us to test females’ fidelity at the islet scale within the GLS area, as the accuracy of ARGOS locations is too low (Patterson et al. 2010; Shimada et al. 2021) to detect possible nesting site shifts. Therefore, this question remains open for now, and the highly fragmented nature of the GLS nesting habitat will provide a suitable study area to investigate the scale of sea turtles site fidelity with more accuracy in the future. Complementary evidence can be drawn from the CMR data. Based on the importance of the RP dataset, we can confidently conclude that the probability of nesting area shifts is low over seven consecutive nesting seasons as the re-sighting rate reported on both nesting areas was significantly different (57.0% ± 10.5, n = 7 in the RP area over the study period, while null in the GLS). Here again, these results strongly point towards a distinction between reproductive female populations using these two nesting areas. Those conclusions should be moderated by the low number of flipper-tagged turtles in the GLS area (n = 15), which does not allow us to totally rule out the possibility of occasional area shifts over separate nesting seasons. The remote and hard-to-reach nature of the nesting islets (Bourgogne et al. 2024c) have acted as a strong logistical hindrance and limited the sampling effort on site.
RkJQdWJsaXNoZXIy MjE1NDI=