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| Registros recuperados: 11 | |
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| Derville, Solene; Jean, Claire; Dalleau, Mayeul; Le Gal, Jean-yves; Ciccione, Stephane; Bourjea, Jerome. |
| Situated about 500 km off the Malagasy east coast, the island of Tromelin is a key nesting site for the endangered green turtle, Chelonia mydas, in the south Western Indian Ocean. Nesting turtles found in this isolated island have been closely monitored since the 1970s, but the most recent estimates of nesting parameters date from 1986. Using mark-recapture data, track counts, and nests monitoring data collected over the 2009/2010 nesting peak, reproductive characteristics, population size, and offspring production were updated and discussed in the light of the track survey undertaken from 1986 to 2010. Females showed a consistent reproductive behaviour compared with previous studies in terms of clutch frequency (2.75 +/- 1.46) and nesting success (0.65).... |
| Tipo: Text |
Palavras-chave: Reptilia Testudines: Cheloniidae Chelonia mydas; Green turtle nesting activity population assessment Indian Ocean Tromelin Island. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00273/38424/36794.pdf |
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| Muths, Delphine; Grewe, R.; Jean, Claire; Bourjea, Jerome. |
| Genetic variation was surveyed at 11 microsatellite loci and at 517 bp of the mitochondrial control region to investigate the presence of genetic stock structure in swordfish (Xiphias gladius) in four proximal localities of the southwest Indian Ocean. One aim of this study was to serve as a preliminary examination for congruency of structure detected by these two genetic markers, prior to conducting a more comprehensive basin-wide survey of the Indian Ocean and nearby surrounding areas. Analyses of multilocus microsatellite genotypes and mitochondrial control region sequences both revealed a great homogeneity between samples. Genetic diversity detected at the regional scale was not significantly higher than detected at the local scale. Results suggest that... |
| Tipo: Text |
Palavras-chave: Indian Ocean; Population genetic; MtDNA; Microsatellites; Swordfish. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6455.pdf |
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| Jensen, Michael P.; Dalleau, Mayeul; Gaspar, Philippe; Lalire, Maxime; Jean, Claire; Ciccione, Stéphane; Mortimer, Jeanne A.; Quillard, Mireille; Taquet, Coralie; Wamukota, Andrew; Leroux, Géraud; Bourjea, Jerome. |
| Understanding how ocean currents impact the distribution and connectivity of marine species, provides vital information for the effective conservation management of migratory marine animals. Here, we used a combination of molecular genetics and ocean drift simulations to investigate the spatial ecology of juvenile green turtle (Chelonia mydas) developmental habitats, and assess the role of ocean currents in driving the dispersal of green turtle hatchlings. We analyzed mitochondrial (mt)DNA sequenced from 358 juvenile green turtles, and from eight developmental areas located throughout the Southwest Indian Ocean (SWIO). A mixed stock analysis (MSA) was applied to estimate the level of connectivity between developmental sites and published genetic data from... |
| Tipo: Text |
Palavras-chave: Chelonia mydas; Green turtle; Juvenile; MtDNA; Drifting simulation; Connectivity; Mixed stock analysis; Southwest Indian Ocean. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00612/72443/71398.pdf |
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| Bourjea, Jerome; Mortimer, Jeanne A.; Garnier, Julie; Okemwa, Gladys; Godley, Brendan J.; Hughes, George; Dalleau, Mayeul; Jean, Claire; Ciccione, Stephane; Muths, Delphine. |
| To refine our understanding of the spatial structure of the green turtle (Chelonia mydas) populations in the South West Indian Ocean (SWIO), we analysed patterns of mitochondrial DNA (396 base pairs control region fragment) variation among 171 samples collected at five distinct locations (Kenya, Northern Mozambique, and three locations in the Republic of Seychelles: the Granitic, Amirantes, and Farquhar groups) and compared them to genetic data (n = 288), previously collected from 10 southern locations in the SWIO. We also analysed post-nesting satellite tracks (n = 4) from green turtles nesting in the Amirantes group. Pairwise comparisons of haplotype frequencies showed significant genetic differentiation amongst rookeries and suggest that the SWIO hosts... |
| Tipo: Text |
Palavras-chave: Indian Ocean; MtDNA; Satellite tracking; Phylogeography; Management unit; Chelonia mydas. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00266/37732/36062.pdf |
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| Mulochau, Thierry; Jean, Claire; Gogendeau, Pierre; Ciccione, Stéphane. |
| Young green turtles, Chelonia mydas, frequent the Syringodium isoetifolium seagrass beds on Reunion’s inner reef flats of fringing reefs, where they come to feed. Photographs of a green turtle looking for and eating the snake sea cucumber. Synapta maculata, were taken for the first time at Reunion Island. S. maculata is a sea cucumber species that was frequently observed on the inner reef flats and on the back-reef depression, but these abundances seem to be decreasing in recent years. Studies of S. maculata populations are needed to monitor changes in densities of this species, which has an important ecosystem role, as well as other observations to determine whether this case of green sea turtle predation is an isolated one or whether S. maculata may... |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00685/79700/82486.pdf |
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| Chambault, Philippine; Dalleau, Mayeul; Nicet, Jean-benoit; Mouquet, Pascal; Ballorain, Katia; Jean, Claire; Ciccione, Stéphane; Bourjea, Jerome. |
| Background A strong behavioural plasticity is commonly evidenced in the movements of marine megafauna species, and it might be related to an adaptation to local conditions of the habitat. One way to investigate such behavioural plasticity is to satellite track a large number of individuals from contrasting foraging grounds, but despite recent advances in satellite telemetry techniques, such studies are still very limited in sea turtles. Methods From 2010 to 2018, 49 juvenile green turtles were satellite tracked from five contrasting feeding grounds located in the South-West Indian Ocean in order to (1) assess the diel patterns in their movements, (2) investigate the inter-individual and inter-site variability, and (3) explore the drivers of their daily... |
| Tipo: Text |
Palavras-chave: Chelonia mydas; Home range; Satellite tracking; Diel pattern; Tidal cycle. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00601/71269/69659.pdf |
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| Bourjea, Jerome; Dalleau, Mayeul; Jean, Claire; Ciccione, Stephane. |
| Dans la suite de la mission à Europa en 2011, des missions menées depuis 2005 par les équipes d’Ifremer et de Kélonia, et dans le cadre de l’Action 4.2.3 du Plan National d’Action (PNA) tortues marines dans les îles Eparses, l’objectif de cette mission à Glorieuses et à Juan de Nova a été de continuer à acquérir des données sur la dynamique spatio-temporelle des immatures de tortues vertes présentes dans les îles Eparses. Plus précisément, cette mission a eu pour objectif de : 1- continuer la série longue de marquage –relecture de tortues vertes juvéniles présentes dans le lagon des Glorieuses et de Juan de Nova ainsi que les suivis de croissance des individus recapturés, 2- déterminer le comportement spatial à fine échelle des tortues vertes juvéniles... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00260/37095/35605.pdf |
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| Chambault, Philippine; Hattab, Tarek; Mouquet, Pascal; Bajjouk, Touria; Jean, Claire; Ballorain, Katia; Ciccione, Stéphane; Dalleau, Mayeul; Bourjea, Jerome. |
| Despite the large number of species distribution modelling (SDM) applications driven by tracking data, individual information is most of the time neglected and traditional SDM approaches commonly focus on predicting the potential distribution at the species or population‐level. By running classical SDMs (population approach) with mixed models including a random factor to account for the variability attributable to individual (individual approach), we propose an innovative five‐steps framework to predict the potential and individual‐level distributions of mobile species using GPS data collected from green turtles. Pseudo‐absences were randomly generated following an environmentally‐stratified procedure. A negative exponential dispersal kernel was... |
| Tipo: Text |
Palavras-chave: GPS tracking; Green turtles; Indian Ocean; Pseudo-absences; Shannon index; Spatial modelling. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79412/81963.pdf |
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| Jean, Claire; Bourjea, Jerome; Jouen, Emmanuel; Taquet, Marc. |
| Stock structure of swordfish (Xiphias gladius Linnaeus, 1758) from four areas of the South West Indian Ocean was conducted using Restriction Fragment Length Polymorphism (RFLP) on mtDNA control region and six amplified microsatellite loci. No significant differences were found among the four locations using either molecular technique. Most variability was found within populations, with only a small proportion of variation among samples, suggesting a unique stock of swordfish in the South West Indian Ocean. The sample size of this study is too small to reveal significant structure among the sampling locations. These results are baseline for a future larger scale project in the whole Indian Ocean. |
| Tipo: Text |
Palavras-chave: Indian Ocean; Microsatellite loci; MtDNA; Xiphias gladius; Swordfish. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2313.pdf |
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| Jean, Claire; Ciccione, Stephane; Ballorain, Katia; Georges, Jean-yves; Bourjea, Jerome. |
| Reunion Island in the south-west Indian Ocean once had significant nesting populations of marine turtles but they declined rapidly after human colonization. In 1996, after regular sightings of turtles offshore, an aerial survey programme was initiated to monitor the occurrence of marine turtles and their distribution along the west coast of the island Between 1998 and 2008, along a 30-km coastline transect between Saint Leu and Saint Paul, a total of 1,845 marine turtle sightings were recorded during 146 flights with an ultralight aircraft The mean number of turtle sightings per survey increased significantly between 1998 and 2008, and a variety of sizes were recorded throughout the year Marine turtles were found over coral reef zones and on the outer reef... |
| Tipo: Text |
Palavras-chave: Abundance; Aerial survey; Conservation; Indian Ocean; Marine turtles; Reunion Island. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00005/11588/9280.pdf |
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| Registros recuperados: 11 | |
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