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| Bourjea, Jerome; Benhamou, Simon; Mouquet, Pascal; Quod, Jean-pascal. |
| Les objectifs de la missions étaient les suivants: Composante 1 « Tortue » : cette composante est divisée en deux volets : (i) Etude des Processus de navigation des tortues vertes dans le sud ouest de l'océan Indien. Sur la base de 12 tortues déplacées à 100 milles de leur plage de ponte, en direction du sud ouest, afin de disposer d'un point de lâcher éloigné des principales îles de la région (Comores, Mayotte, Madagascar, Seychelles), les processus de navigation et d’orientation en fonction du champs magnétique terrestre et des courants seront étudiées grâce à des balises Argos. Cette composante est très semblable au travail qui a été menée lors de la mission Glorieuses 2008. (ii) Importance des îles du Sud Ouest de l’océan Indien en tant qu’habitat de... |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00244/35517/34022.pdf |
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| Bourjea, Jerome; Benhamou, Simon. |
| Les objectifs de cette mission étaient les suivants : Composante 1 : Etude des Processus de navigation des tortues vertes dans le sud ouest de l'Océan Indien. Sur la base de 12 tortues déplacées à 100 milles de leur plage de ponte, en direction de l'ouest, afin de disposer d'un point de lâcher éloigné des principales îles de la région (Comores, Mayotte, Madagascar, Seychelles), les processus de navigation et d’orientation en fonction du champs magnétique terrestre et des courants seront étudiées grâce à des balises Argos. Composante 2 : Importance des îles du Sud Ouest de l’océan Indien en tant qu’habitat de développement pour les tortues marines. Dans la continuité des missions réalisées ces 3 dernières années dans les îles Eparses, une campagne de... |
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| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/00244/35516/34021.pdf |
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| Girard, Charlotte; Sudre, Joël; Benhamou, Simon; Roos, David; Luschi, Paolo. |
| As open sea navigators, green turtles Chelonia mydas have to deal with oceanic currents. These currents may have a mechanical influence, forcing turtles away from their desired course, but they may also provide information to navigating turtles by bringing chemical cues down-current from their target area. In the present paper, we have introduced new path analysis methods, coupling remote-sensing oceanographic data and satellite-tracking data in order to test these hypotheses. These methods were exemplified on the homing routes of 3 green turtles nesting on Europa, an isolated island in the southern part of Mozambique Channel. The turtles, displaced by ship east-southeast from Europa, returned to their nesting island in 13 to 59 d, following long,... |
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Palavras-chave: Sea turtle; Satellite telemetry; Oceanography; Navigation; Homing; Current drift. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1984.pdf |
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| Luschi, Paolo; Benhamou, Simon; Girard, Charlotte; Ciccione, Stéphane; Roos, David; Sudre, Joël; Benvenuti, Silvano. |
| Marine turtles are renowned long-distance navigators, able to reach remote targets in the oceanic environment; yet the sensory cues and navigational mechanisms they employ remain unclear [1-3]. Recent arena experiments indicated an involvement of magnetic cues in juvenile turtles' homing ability after simulated displacements [4, 5], but the actual role of geomagnetic information in guiding turtles navigating in their natural environment has remained beyond the reach of experimental investigations. In the present experiment, twenty satellite-tracked green turtles (Chelonia mydas) were transported to four open-sea release sites 100-120 km from their nesting beach on Mayotte island in the Mozambique Channel; 13 of them had magnets attached to their head [6]... |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2407.pdf |
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| Benhamou, Simon; Sudre, Joël; Bourjea, Jerome; Ciccione, Stephane; De Santis, Angelo; Luschi, Paolo. |
| Background: Laboratory and field experiments have provided evidence that sea turtles use geomagnetic cues to navigate in the open sea. For instance, green turtles (Chelonia mydas) displaced 100 km away from their nesting site were impaired in returning home when carrying a strong magnet glued on the head. However, the actual role of geomagnetic cues remains unclear, since magnetically treated green turtles can perform large scale (.2000 km) post-nesting migrations no differently from controls. Methodology/Principal Findings: In the present homing experiment, 24 green turtles were displaced 200 km away from their nesting site on an oceanic island, and tracked, for the first time in this type of experiment, with Global Positioning System (GPS), which is able... |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00048/15958/13390.pdf |
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| Dalleau, Mayeul; Ciccione, Stephane; Mortimer, Jeanne A.; Garnier, Julie; Benhamou, Simon; Bourjea, Jerome. |
| Changes in phenology, the timing of seasonal activities, are among the most frequently observed responses to environmental disturbances and in marine species are known to occur in response to climate changes that directly affects ocean temperature, biogeochemical composition and sea level. We examined nesting seasonality data from long-term studies at 8 green turtle (Chelonia mydas) rookeries that include 21 specific nesting sites in the South-West Indian Ocean (SWIO). We demonstrated that temperature drives patterns of nesting seasonality at the regional scale. We found a significant correlation between mean annual Sea Surface Temperature (SST) and dates of peak nesting with rookeries exposed to higher SST having a delayed nesting peak. This supports the... |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00098/20940/18558.pdf |
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| Dalleau, Mayeul; Benhamou, Simon; Sudre, Joel; Ciccione, Stephane; Bourjea, Jerome. |
| While our understanding of the early oceanic developmental stage of sea turtles has improved markedly over recent decades, the spatial context for this life history stage remains unknown for Indian Ocean loggerhead turtle populations. To address this gap in our knowledge, 18 juvenile loggerheads were satellite tracked from Reunion Island (21.2A degrees S, 55.3A degrees E) between 2007 and 2011. Nine turtles swam north toward Oman (20.5A degrees N, 58.8A degrees E), where one of the world's largest rookeries of loggerheads is located. Three individuals traveled south toward South Africa and Madagascar, countries that also host loggerhead nesting grounds. Fourteen of the transmitters relayed diving profiles. A dichotomy between diurnal and nocturnal diving... |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00210/32173/32178.pdf |
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