Project description:The aim of the study was to monitor and analyse injured and diseased loggerhead sea turtles (Caretta caretta) plasma proteome profiles during their recovery period in rescue centre within different age and recovery period groups, and determine the potential biomarkers that can be used in diagnostics.
Project description:The head of the sea turtle is susceptible to congenital, developmental, traumatic, and infectious disorders. An accurate interpretation and thorough understanding of the anatomy of this region could be useful for veterinary practice on sea turtles. The purpose of this study was to develop an interactive two-dimensional (2D) atlas viewing software of the head of the loggerhead sea turtle (Caretta caretta) using images obtained via osteology, gross dissections, and computed tomography (CT). The atlas is composed of 10 osteology, 13 gross dissection, 10 sagittal multiplanar reconstructed CT (bone and soft tissue kernels), and 22 transverse CT (bone and soft tissue windows) images. All images were segmented and colored using ITK-SNAP software. The visualization and image assessment were performed using the Unity 3D platform to facilitate the development of interactive content in 2D. This atlas can be useful as an interactive anatomic resource for assessment of the head of loggerhead sea turtles.
Project description:The relationship between dive behavior and oceanographic conditions is not well understood for marine predators, especially sea turtles. We tagged loggerhead turtles (Caretta caretta) with satellite-linked depth loggers in the Gulf of Mexico, where there is a minimal amount of dive data for this species. We tested for associations between four measurements of dive behavior (total daily dive frequency, frequency of dives to the bottom, frequency of long dives and time-at-depth) and both oceanographic conditions (sea surface temperature [SST], net primary productivity [NPP]) and behavioral mode (inter-nesting, migration, or foraging). From 2011-2013 we obtained 26 tracks from 25 adult female loggerheads tagged after nesting in the Gulf of Mexico. All turtles remained in the Gulf of Mexico and spent about 10% of their time at the surface (10% during inter-nesting, 14% during migration, 9% during foraging). Mean total dive frequency was 41.9 times per day. Most dives were ≤ 25 m and between 30-40 min. During inter-nesting and foraging, turtles dived to the bottom 95% of days. SST was an important explanatory variable for all dive patterns; higher SST was associated with more dives per day, more long dives and more dives to the seafloor. Increases in NPP were associated with more long dives and more dives to the bottom, while lower NPP resulted in an increased frequency of overall diving. Longer dives occurred more frequently during migration and a higher proportion of dives reached the seafloor during foraging when SST and NPP were higher. Our study stresses the importance of the interplay between SST and foraging resources for influencing dive behavior.
Project description:Microbial communities provide essential information about host ecology and could be helpful as a tool to improve species conservation efforts. However, microbes can also infect and compromise the host development process and viability. Caretta caretta is the most widespread marine turtle species in the Mediterranean basin and is the only species of sea turtle nesting along the Italian coasts. Little is known about the microbiota composition of the nest of sea turtles and its correlation with hatching failures. In this study, the microbial composition of two nests of C. caretta featuring different rates of hatching success from a nesting beach in Lampedusa (Italy) was analyzed and compared. The bacterial community was determined using culture-dependent methods and next-generation sequencing based on 16S rRNA gene metabarcoding analysis. Our results showed five dominant bacterial phyla (Proteobacteria, Bacteroidetes, Actinobacteria, Verrucomicrobia, and Firmicutes) and indicated different bacterial families (Pseudomonadaceae and Brucellaceae) as likely causes of hatching failures. Besides, our findings demonstrated the nests' active role in modulating the sand's bacterial communities. This study suggests microbiological analysis could be a valuable tool in monitoring nests to take preventive actions and reduce hatching failures.
Project description:The colonisation of new suitable habitats is crucial for species survival at evolutionary scale under changing environmental conditions. However, colonisation potential may be limited by philopatry that facilitates exploiting successful habitats across generations. We examine the mechanisms of long distance dispersal of the philopatric loggerhead sea turtle (Caretta caretta) by analysing 40 sporadic nesting events in the western Mediterranean. The analysis of a fragment of the mitochondrial DNA and 7 microsatellites of 121 samples from 18 of these nesting events revealed that these nests were colonising events associated with juveniles from distant populations feeding in nearby foraging grounds. Considering the temperature-dependent sex determination of the species, we simulated the effect of the incubation temperature and propagule pressure on a potential colonisation scenario. Our results indicated that colonisation will succeed if warm temperature conditions, already existing in some of the beaches in the area, extend to the whole western Mediterranean. We hypothesize that the sporadic nesting events in developmental foraging grounds may be a mechanism to overcome philopatry limitations thus increasing the dispersal capabilities of the species and the adaptability to changing environments. Sporadic nesting in the western Mediterranean can be viewed as potential new populations in a scenario of rising temperatures.
Project description:Exploring a trade-off between quantity and quality of offspring allows differences in the fitness between alternative life histories to be accurately evaluated. We addressed the mechanism that maintains alternative life histories (small oceanic planktivores vs. large neritic benthivores) observed in a loggerhead sea turtle (Caretta caretta) population, which has been suggested to be environmental, based on the lack of genetic structure and a large difference in reproductive output. We examined whether maternal foraging habitat affects offspring quality, by measuring the morphology, emergence success, and righting response of hatchlings following incubation in a common open sand area over the whole nesting season at Yakushima Island, Japan, and by recording early growth and survival of offspring that were reared in a common environment at a Japanese aquarium. Furthermore, we tested whether sea turtles adjust egg size in response to temporal shifts of the incubation environment. There were no significant differences in any hatchling traits between oceanic and neritic foragers (which were classified by stable isotope ratios), except for clutches laid during the warmest period of the nesting season. There were also no significant differences in the growth and survival of offspring originating from the two foragers. The size of eggs from both foragers significantly increased as the season progressed, even though the rookery had heavy rainfall, negating the need to counteract heat-related reduction in hatchling morphology. In comparison, the sizes of adult body and clutches from both foragers did not vary significantly. The results further support our previous suggestions that the size-related foraging dichotomy exhibited by adult sea turtles does not have a genetic basis, but derives from phenotypic plasticity. Adjustment in reproductive investment may be associated with: (1) predation avoidance, (2) founder effect, and/or (3) annual variation in egg size.
Project description:Microbes have central roles in the development and health of animals, being the introduction of specific microbial species a potential conservation strategy to protect animals from emerging diseases. Thus, insight into the microbiota of the species and their habitats is essential. In this manuscript, we report for the first time the bacterial composition of all the components (eggshells of hatched and unhatched eggs, internal content of unhatched eggs, intestinal content of hatchling and pipping sea turtles, and sand) of three nesting beaches of Caretta caretta along the Italian coasts of the Mediterranean Sea. The analysis of 26 amplicon samples was carried out using next-generation sequencing analysis, targeting V3-V4 regions of the bacterial 16S rRNA gene. Samples featured mainly Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes, whose percentages depended on the sample type. Our results showed that, although from different sampling sites, the internal content of the unhatched eggs, intestinal content of hatchling and pipping sea turtles share the microbiota, which was yet different from that of eggshells and sand of the same nesting beach. This study suggests the maternal and environmental influence alongside a protective role of eggshells in shaping the egg microbiota of Caretta caretta sea turtles.