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- Hatchery efficiency for turtle conservation in Cabo VerdePublication . Martins, Samir; Ferreira-Veiga, Nádia; Rodrigues, Zuleika; Querido, Adélcio; Loureiro, Nuno de Santos; Freire, Kátia; Abella, Elena; Oujo, Carolina; Marco, AdolfoThis paper evaluated the efficiency of beach hatcheries as a conservation tool for threatened sea turtle clutches. During six nesting seasons (2013 to 2018), several thousand high-risk clutches from loggerhead turtles (Caretta caretta) were relocated to a hatchery constructed on the same beach, within the Sea Turtle Natural Reserve (STNR, Boa Vista Island, Cabo Verde). Some parameters like hatching success; incubation period, hatchlings’ morphology and their behavioral response were compared to in-situ clutches.
- Hatchery efficiency as a conservation tool in threatened sea turtle rookeries with high embryonic mortalityPublication . Martins, Samir; Ferreira-Veiga, Nádia; Rodrigues, Zuleika; Querido, Adélcio; Loureiro, Nuno de Santos; Freire, Kátia; Abella, Elena; Oujo, Carolina; Marco, AdolfoSea turtles are globally endangered and facing anthropogenic threats. To mitigate the negative impacts on sea turtle populations, different conservation strategies have been developed and implemented. For instance, when an endangered population suffers a high embryonic mortality from predation, human poaching, beach flooding or erosion, the relocation of clutches to safer and controlled areas can lower these threats. However, the use of hatcheries is controversially discussed, with some previous studies reporting negative results such as low hatching success, skewed sex ratio or phenotypic alterations of hatchlings. In this study, we evaluated the efficiency of beach hatcheries compared to in-situ incubation in Cabo Verde using data from six nesting seasons (2013-2018). During this study, several thousand high-risk clutches from loggerhead turtle (Caretta caretta Linnaeus, 1758) were relocated to a hatchery constructed within the Sea Turtle Natural Reserve (STNR, Boa Vista Island). Our findings confirmed that the in-situ nests within the STNR have extremely high egg mortality that is usually over 70%. Mean hatching success of clutches relocated to hatcheries was significantly higher than in-situ clutches with mean values between 70 and 85%. No significant differences were observed in the incubation period, the size and the behavioural response of hatchlings between relocated and in-situ clutches. As long as a sea turtle population is endangered and hatching success is low, clutch relocation programs which are designed to have an impact at the population level, are considered an efficient tool that contributes to its recuperation. Nevertheless, strict recommendations that increase hatching success while maintaining natural hatchling phenotype must be implemented.
- High variability in nest site selection in a loggerhead turtle rookery, in Boa Vista Island, Cabo VerdePublication . Martins, Samir; Patrício, Rita; Clarke, Leo J.; Loureiro, Nuno de Santos; Marco, AdolfoAmong sea turtles, nest site selection is a crucial factor for hatching success and population viability. The relocation of otherwise doomed clutches to safe hatcheries has been widely promoted as a conservation strategy, although this may promote artificial selection of poorly adapted genotypes. In this study, we used multiyear spatial nesting data of individual loggerhead turtles (Caretta caretta) from one of the largest Atlantic rookeries, in Cabo Verde, across six consecutive nesting seasons (2013-2018), to identify spatial nesting patterns, assess how individual nest site selection is influenced by female size and age, and estimate the impacts on the reproductive output. Although females nested across the entire beach width, they preferentially nested in the middle of the beach, avoiding to nest both close to the tideline and close to the vegetation line. Hatching success decreased towards the waterline, while the risk of nest inundation or predation was high, regardless of nest location. In general, females showed high variability in nest site selection, except larger females (> 93 cm curved carapace length) that showed higher repeatability (r = 0.50, SE = 0.14, 95% CI: 0.16-0.72) in distances to the vegetation. We therefore suggest that the relocation of doomed clutches should be considered for this endangered rookery, as clutch relocation should not substantially distort the gene pool, assuming nest choice is a heritable trait. In addition, we recommend the preservation of beach vegetation, particularly in areas with human development.