Loggerhead turtles nesting in the Mediterranean Sea exhibit remarkable genetic structuring. This paper tests the hypothesis that young loggerhead turtles from different rookeries do not distribute ...homogeneously among the major Mediterranean foraging grounds, due to a complex pattern of surface currents. We extracted long fragments of mitochondrial DNA from 275 stranded or bycaught juvenile turtles from six foraging grounds (Catalano-Balearic Sea, Algerian basin, Tyrrhenian Sea, Adriatic Sea, northern Ionian Sea and southern Levantine Sea). We used a Bayesian mixed-stock analysis to estimate the contributions from rookeries in the Mediterranean, the North-west Atlantic and Cape Verde to the studied foraging grounds. Differences were found in the relative contribution of juvenile turtles of Atlantic and Mediterranean origin to each foraging ground. A decreasing proportion of Atlantic juveniles was detected along the main surface current entering the Mediterranean, with a high prevalence of turtles from eastern Florida in the Algerian basin and lower numbers elsewhere. In regard to the turtles of Mediterranean origin, juveniles from Libya prevailed in central and western Mediterranean foraging grounds other than the Algerian basin. Conversely, the Adriatic Sea was characterised by a large presence of individuals from western Greece, while the southern Levantine Sea was inhabited by a heterogeneous mix of turtles from the eastern Mediterranean rookeries (Turkey, Lebanon and Israel). Overall, the distribution of juveniles may be related to surface circulation patterns in the Mediterranean and suggests that fisheries might have differential effects on each population depending on the overlap degree between foraging and fishing grounds.
•Toxoplasma gondii DNA was detected in three stranded dolphins on the Israeli coast.•In one case, coinfection of Toxoplasma gondii and herpesvirus was confirmed.•Lung pathology was observed in all ...examined cases.
Toxoplasma gondii has been described in several marine mammals around the world including numerous species of cetaceans, yet infection and transmission mechanisms in the marine environment are not clearly defined. The Israel Marine Mammal Research and Assistance Center has been collating a database of all marine mammal stranding events along the country’s national coastlines since 1993. In this study, we describe the molecular detection and characterisation of T. gondii in three common bottlenose dolphins (Tursiops truncatus) including one case of coinfection with herpesvirus. The animals were found stranded on the Mediterranean coast of Israel in May and November 2013. In one of the three cases, the dolphin was found alive and admitted to intensive care. To our knowledge, this is the first report of T. gondii infection of marine mammals in the Eastern Mediterranean Sea. As this parasite acts as an indicator for marine pollution and marine mammal health, we believe these findings add important information regarding the state of the environment in this region.
As the loggerhead turtle (Caretta caretta) is a philopatric species with a strong genetic structure, the analysis of mtDNA can be used to track evolutionary and colonisation events. In this study we ...use a genetic approach to understand the population structure of C. caretta in the Mediterranean Sea and to test whether loggerheads could have colonised the Mediterranean during the Pleistocene and survived the cold phases in warm refugia. We amplified a long mtDNA D-loop fragment (815bp) from 168 dead hatchlings sampled from a selection of rookeries in the Eastern Mediterranean: Libya, Israel, Lebanon, Cyprus and Greece. Previously published data from Turkey and Calabria (Southern Italy) were also included in the analyses. The population nesting in Libya emerged as the oldest population in the Mediterranean, dating from the Pleistocene ca. 65,000years ago (20,000–200,000). This reveals that the Libyan population might have settled in the Mediterranean basin before the end of the last glacial period. The remaining nesting sites, except Calabria, were subsequently colonised as the population expanded. The populations nesting in Eastern Turkey and Western Greece settled ca. 30,000years ago (10,000–100,000), whereas the remaining populations originated as a result of a more recent Holocenic expansion. As Calabria presented a unique Atlantic haplotype, found nowhere else in the Mediterranean, we consider this nesting site as the result of an independent colonisation event from the Atlantic and not the recent spread of Mediterranean populations. This reveals that the current genetic structure of C. caretta rookeries in the Mediterranean would be the result of at least two colonisation events from the Atlantic, the oldest one in Libya and a most recent in Calabria, combined with local extinctions during Pleistocenic glaciations and re-colonisations from glacial refugia in Libya, Eastern Turkey and Western Greece.
► Genetic structuring for loggerhead turtles exists within the Mediterranean basin. ► Four differentiated genetic groups can be defined in the Mediterranean. ► Colonisation of the Mediterranean from the Atlantic dates from the Pleistocene. ► Libya hosts the oldest population in the basin, colonised ca. 65,000 years ago (20,000-200,000). ► Libya, and likely Eastern Turkey and Western Greece, appeared as glacial refugia.
Loggerhead turtles Caretta caretta use a wide variety of foraging strategies, and some populations forage in sub-optimal habitats. Different foraging strategies may not be equivalent in terms of ...fitness and may result in differences in adult body size and clutch size among populations. Accordingly, we tested whether differences in clutch size among rookeries in the Mediterranean Sea are related to differential use of foraging grounds of contrasting productivity. Stable isotope ratios of carbon and nitrogen of turtle hatchlings from 8 Mediterranean rookeries were used to characterise the foraging grounds of their mothers. Clutch size was also studied in each rookery to assess reproductive output linked to foraging ground productivity. According to stable isotope ratios, most of the females nesting in the considered rookeries foraged in the southern Ionian Sea. The highly productive Adriatic/northern Ionian Sea region was mainly used by females nesting in western Greece. The explanation for these patterns might be linked to water circulation patterns and drifting trajectories followed during developmental migrations, which might determine individual knowledge on the location of productive foraging patches. Average clutch size in each rookery was positively correlated to the proportion of females accessing highly productive areas such as the Adriatic/northern Ionian Sea. This has a strong influence on reproductive output, and hence females using the most productive foraging grounds had the largest clutch sizes.
Marine turtles have been traditionally considered model organisms to study sex-biased behaviour and dispersal. Although female philopatry has been identified in the loggerhead turtle, with adult ...females returning to specific locations to nest, studies on the philopatry and breeding migrations of males remain limited. In this study we analysed 152 hatchlings using 15 microsatellite markers. Each individual came from a different nest from samples taken at 8 nesting grounds in the Mediterranean. Our results revealed the existence of 5 genetically differentiated units, mostly due to restricted gene flow for both sexes. This supports existing satellite tracking studies that suggest that mating occurs close to nesting grounds in this region. The 5 management units identified within the Mediterranean included nesting grounds from (1) Libya and Cyprus, (2) Israel, (3) Lebanon, (4) Turkey and (5) Greece. The genetic similarity between distant nesting areas (i.e. Libya and Cyprus) suggests the presence of a more complex pattern of breeding behaviour. Three possible hypotheses, that remain to be tested in future studies, could explain this result: (1) mating might take place in common foraging grounds; (2) mating could occur en route while migrating to/from the breeding grounds; or (3) recent colonisation events could connect the 2 nesting grounds. Overall, our work suggests that widespread male-mediated gene flow between loggerhead nesting grounds is likely to have been previously overstated although opportunistic breeding patterns might connect some widely separated areas.
Marine turtles have been traditionally considered model organisms to study sex-biased behaviour and dispersal. Although female philopatry has been identified in the loggerhead turtle, with adult ...females returning to specific locations to nest, studies on the philopatry and breeding migrations of males remain limited. In this study we analysed 152 hatchlings using 15 microsatellite markers. Each individual came from a different nest from samples taken at 8 nesting grounds in the Mediterranean. Our results revealed the existence of 5 genetically differentiated units, mostly due to restricted gene flow for both sexes. This supports existing satellite tracking studies that suggest that mating occurs close to nesting grounds in this region. The 5 management units identified within the Mediterranean included nesting grounds from (1) Libya and Cyprus, (2) Israel, (3) Lebanon, (4) Turkey and (5) Greece. The genetic similarity between distant nesting areas (i.e. Libya and Cyprus) suggests the presence of a more complex pattern of breeding behaviour. Three possible hypotheses, that remain to be tested in future studies, could explain this result: (1) mating might take place in common foraging grounds; (2) mating could occur en route while migrating to/from the breeding grounds; or (3) recent colonisation events could connect the 2 nesting grounds. Overall, our work suggests that widespread male-mediated gene flow between loggerhead nesting grounds is likely to have been previously overstated although opportunistic breeding patterns might connect some widely separated areas.
Marine turtles have been traditionally considered model organisms to study sex-biased behaviour and dispersal. Although female philopatry has been identified in the loggerhead turtle, with adult ...females returning to specific locations to nest, studies on the philopatry and breeding migrations of males remain limited. In this study we analysed 152 hatchlings using 15 microsatellite markers. Each individual came from a different nest from samples taken at 8 nesting grounds in the Mediterranean. Our results revealed the existence of 5 genetically differentiated units, mostly due to restricted gene flow for both sexes. This supports existing satellite tracking studies that suggest that mating occurs close to nesting grounds in this region. The 5 management units identified within the Mediterranean included nesting grounds from (1) Libya and Cyprus, (2) Israel, (3) Lebanon, (4) Turkey and (5) Greece. The genetic similarity between distant nesting areas (i.e. Libya and Cyprus) suggests the presence of a more complex pattern of breeding behaviour. Three possible hypotheses, that remain to be tested in future studies, could explain this result: (1) mating might take place in common foraging grounds; (2) mating could occur en route while migrating to/from the breeding grounds; or (3) recent colonisation events could connect the 2 nesting grounds. Overall, our work suggests that widespread male-mediated gene flow between loggerhead nesting grounds is likely to have been previously overstated although opportunistic breeding patterns might connect some widely separated areas.
Loggerhead turtles Caretta caretta use a wide variety of foraging strategies, and some populations forage in sub-optimal habitats. Different foraging strategies may not be equivalent in terms of ...fitness and may result in differences in adult body size and clutch size among populations. Accordingly, we tested whether differences in clutch size among rookeries in the Mediterranean Sea are related to differential use of foraging grounds of contrasting productivity. Stable isotope ratios of carbon and nitrogen of turtle hatchlings from 8 Mediterranean rookeries were used to characterise the foraging grounds of their mothers. Clutch size was also studied in each rookery to assess reproductive output linked to foraging ground productivity. According to stable isotope ratios, most of the females nesting in the considered rookeries foraged in the southern Ionian Sea. The highly productive Adriatic/northern Ionian Sea region was mainly used by females nesting in western Greece. The explanation for these patterns might be linked to water circulation patterns and drifting trajectories followed during developmental migrations, which might determine individual knowledge on the location of productive foraging patches. Average clutch size in each rookery was positively correlated to the proportion of females accessing highly productive areas such as the Adriatic/northern Ionian Sea. This has a strong influence on reproductive output, and hence females using the most productive foraging grounds had the largest clutch sizes.
Conservation measures are crucial to sustain the marine environment vital. Sea turtles become an important conservation tool as their populations face major anthropogenic threats worldwide, at sea ...and on their nesting beaches. Most of the populations are declining. Rescuing sea turtles go beyond just saving these taxa because marine turtles also serve as flagship and umbrella species that help to increase public awareness to conservation issues in general. Conservation efforts are focused on applying effective management plans to save these threatened populations by primarily protecting their habitats and developing methods to rescue injured individuals. In this study, I focused on four aspects of marine turtle ecology and conservation. First, I identified the spatiotemporal priority habitats of loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtles in the eastern Mediterranean Sea using satellite transmitters. Since fishing is the major threat turtles face worldwide, I than characterized Israel's fishery impacts on sea turtle populations. Studying the turtle encounters with fishing activities led me to the third goal of this study: enhancing the medical knowledge required for better treatment of sea turtles, focusing on diagnostics and husbandry. I defined hematological and biochemical blood values of post drowning and healthy sea turtles for reference use in turtle rescue centers. Finally, I developed an optimal medical treatment facility for intensive care of sea turtles and provided recommendations to help the sea turtle populations.In this study, tracked sea turtles (n=15) spent their time foraging in a median of 137 km2 core home range (50% kernel density estimation). Home range size increased to a median of 464 km2 during the inter-nesting season. Migration varied widely, most turtles migrated short distances (~300 km) within the south-eastern Levant Sea. Home range depth and distance from shore were the same areas as the high fishing effort revealed by this study, and this overlap increases the risk for turtles. Gillnets and trawlers were found to be the main threats to sea turtles in this area (Trawler's catch rate of 0.015 turtles/hour) responsible for almost 3,000 turtles caught annually. The mortality rate in Israeli waters due to trawling and the stranding density was found as the highest in the Mediterranean.Incidental capture by fishing is commonly associated with forced apnea, which seems to be the major cause of death from a turtle’s encounter with all of the common fishing methods worldwide. In this study, I exhibit the first healthy and drowned turtles (n=163) blood parameters of the eastern Mediterranean Sea that can be used for medical diagnosis, and I suggest to consider a novel treatment - lung lavage in severe drowning cases.In addition, I developed an intensive care tank to fit the specific needs of medical treatment to varied turtle injuries. It allows medical procedures to be performed easily, greatly reduce the turtle’s stress, and elevate the chances of survival of an injured turtle while allowing the caregiver accessibility in treatment and enabling even remote rescue centers to provide the best possible conditions for treatment at the first critical weeks. Saving mature individuals struggling for survival against anthropogenic threats, elevates the population’s survival rate by returning these vital turtles, who succeeded to reach maturity to reproduce in the wild. The blood parameters values for diagnosis and the intensive care tank unit can be highly efficient in turtle rescue centers worldwide. Additionally, conservation recommendations derived from this study, once applied, can mitigate turtle threats in the south eastern Mediterranean and help recover the sea turtle populations in this area, which seems to be a multifunctional habitat for reproduction, migration and foraging.
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