Éditeur(s) : Springer
Résumé : We investigated the habitat use in green turtles exploiting a 13-ha multispecific seagrass meadow at Mayotte Island, south-western Indian Ocean. A phytoecological survey shows the occurrence of eight seagrass species, dominated by Halodule uninervis and Syringodium isoetifolium, distributed according to four distinct seagrass communities along the depth gradient. Direct underwater censuses show that green turtles occurred all over the meadow. Yet when community relative surface area was taken into account green turtles preferentially frequented the most seaward, biomass-richer S. isoetifolium-dominated community, suggesting that green turtles compensate for their intrinsically nutrient-poor herbivorous diet. Additionally, smaller (80 cm standard curved carapace length, SCCL) individuals also preferentially occurred in the most shoreward H. univervis-dominated community where no larger ([80 cm SCCL) individuals were sighted, suggesting habitat use is indicative of diet selection and may reflect size-specific food requirements and physiology.
Marine Biology (0025-3162) (Springer), 2010-12 , Vol. 157 , N. 12 , P. 2581-2590

Droits : 2010 Springer
http://archimer.ifremer.fr/doc/00018/12918/10201.pdf
DOI:10.1007/s00227-010-1520-7
http://archimer.ifremer.fr/doc/00018/12918/

Éditeur(s) : Aquaculture 67 : 260-261
Résumé : An infection caused by a Perkinsus -like parasite has been observed in Ruditapes decussatus from Portugal (Comps and Chagot, 1987). Following a pathological study carried out on clams affected by mortalities in the Algarve area, this parasite was found again, inducing a reaction process in the host. Histological examination reveals the parasite in the connective tissue of different organs. The adjoining tissues, particularly the epithelia, are not affected.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1987/acte-3109.pdf
http://archimer.ifremer.fr/doc/00000/3109/

Éditeur(s) : Conseil International pour l'Exploration de la Mer (CIEM), C. M. 1975/K: 21
Résumé : Following our aim of developing oyster culture in French Guyana and studying the different options available to increase a stock of new oyster species, we were lead to search for possible parasites in Crassostrea rhizophorae. These oysters from the French Guyanese coasts host some gregarine Nematopsis sp. spores, characterized by Comps, Grizel and Tige (1972). Through this work, we conducted some experimental infestation trials between Crassostrea rhizophorae spats parasited by these spores and the most common crab on metropolitan farms Carcinus maenas.
Poursuivant les objectifs de développement de l'ostréiculture en Guyane et étudiant les possibilités d'accroissement d'un stock constitué de nouvelles espèces d'huîtres, nous avons été amenés à rechercher d'éventuels parasites chez Crassostrea rhizophorae. Ces huîtres des côtes de la Guyane française abritent des spores de Grégarines, Nematopsis sp. mises en évidence par COMPS, GRIZEL et TIGE (1972). Au cours de ce travail nous avons réalisé des essais d'infestations expérimentales entre du naissain de Crassostrea rhizophorae parasité par ces spores et le crabe le plus répandu sur les parcs à huîtres métropolitains, Carcinus maenas.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1975/acte-6290.PDF
http://archimer.ifremer.fr/doc/00000/6290/

Résumé : Les 21 et 22 juin 2000, le Département des Ressources Aquacoles a consacré ses journées annuelles à une revue du thème "santé des cheptels" et du dispositif de recherche en pathologie sur les filières poissons, crustacés et mollusques, domaine très stratégique pour l'aquaculture marine française. Les objectifs des ces journées, rappelés par Yves Harache, Directeur du Département, étaient les suivante : • Dresser le bilan des actions de recherche menées par l'Ifremer en pathologie des espèces aquacoles, • Repréciser la stratégie (objectifs/moyens) du Département des Ressources Aquacoles sur le thème "santé des cheptels", • Programmer les actions de recherche à venir, • Stimuler les interactions entre groupes de recherche et laboratoires impliqués. Le présent rapport rend compte du contenu des débats de ces deux journées.

Droits : 2000 Ifremer
http://archimer.ifremer.fr/doc/00164/27547/25711.pdf
http://archimer.ifremer.fr/doc/00164/27547/

Éditeur(s) : Institut Océanographique
Résumé : Afin de mieux comprendre les problèmes de parasitologie des mollusques, il est nécessaire de donner un aperçu rapide sur : les principales espèces de mollusques réellement cultivées dans le monde, la naissance de la conchyliculture, le contexte de développement des recherches de parasitologie.
Océanis (Institut Océanographique), 1976 , Vol. 3 , N. 5 , P. 190-207

Droits : Institut Océanographique
http://archimer.ifremer.fr/doc/00013/12465/9301.pdf
http://archimer.ifremer.fr/doc/00013/12465/

Éditeur(s) : Académie des Sciences
Résumé : Along the French Guiana coast, mainly in the Monsinéry River, there are populations of natural oysters belonging to the species Crassostrea rhizophorae (Guilding). Within the scope of the growth of oyster farming in Guiana, we researched possible parasites of these oysters that are still little studied. This work, conducted based on living and set samples, allowed us to highlight the presence of nematops spores.
Sur la côte de la Guyane française, principalement dans la rivière de Montsinéry existent des populations d'huîtres naturelles appartenant à l'espèce Crassostrea rhizophorae (Guilding). Dans le cadre du développement de l'ostréiculture en Guyane, nous avons recherché des parasites éventuels de ces huîtres encore peu étudiées. Ce travail mené à partir d'échantillons vivants et fixés nous a permis de mettre en évidence la présence de spores nématopsidiennes.
Comptes Rendus Académie Sciences Paris (Académie des Sciences), 1972-09 , Vol. 275 , N. 15 , P. 1693-1695

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1972/publication-3008.pdf
http://archimer.ifremer.fr/doc/00000/3008/

Éditeur(s) : Inter-Research
Résumé : Situated in the north of the Mozambique Channel, Mayotte is the easternmost island of the Comoros Archipelago. From 1998 to 2005, Grande Saziley beach was monitored daily for green turtle Chelonia mydas nesting activity. Track surveys were monitored daily on 5 other adjacent beaches. Although nesting occurs throughout the year, nesting seasonality begins at the end of the wet season and intensifies during the dry season to reach an average nesting peak in June. In order to estimate the number of females nesting in the Saziley site and population trends over the study period, incubation success and number of nests per female and per season were estimated at 0.77 (±0.05 SD) and 3.03 (±0.37) respectively. With an average of 1545 nesting turtles per year (±439), the change in nesting numbers over the study period was so small that the population can be regarded as stable, with an estimated annual mean growth rate of 0.912, confirmation that this population is both stable and in good health. Added support for this argument is demonstrated by the fact that the annual carapace size distribution of nesting females is stable, meaning that the nesting green turtle population of Mayotte is not ageing or rejuvenating. After due consideration of data on other nesting sites in the southwest Indian Ocean, the data from Mayotte emphasizes the fact that the green turtle is not an endangered species in this region. Even if it is still illegally exploited and alterations occur in their different habitats, the green turtle populations of this region seem to have successfully survived all threats during the past century.
Endangered Species Research (1613-4796) (Inter-Research), 2007-10-10 , Vol. 3 , P. 273-282

Droits : 2007 Inter-Research
http://archimer.ifremer.fr/doc/00018/12916/9873.pdf
DOI:10.3354/esr00053
http://archimer.ifremer.fr/doc/00018/12916/

Éditeur(s) : Inter-Research
Résumé : The green turtle Chelonia mydas is classified as endangered because of global declines over the past few centuries due to human exploitation and habitat destruction, particularly the loss of nesting areas. We used the number of tracks as an indicator of breeding female abundance at their nesting sites to study the seasonality and trends of turtles breeding at 3 islands in the SW Indian Ocean: Europa, Tromelin and Grande Glorieuse, over 20 yr. On Tromelin, tracks were counted along the entire nesting beach, but on Europa and Grande Glorieuse counts were limited to a proportion of the island. Europa and Tromelin exhibited similar seasonal patterns, with a well-defined peak during the wet season (November–February), compared to a dry season peak for Grande Glorieuse (March–June). The main season was significantly longer on Grande Glorieuse (288 ± 43 d) than on Europa (218 ± 60 d), with Tromelin intermediate (252 ± 43 d). There was greater variation in the start of a season compared to the median and end at all sites throughout the study. Approximately 7178 ± 3053 (n = 19) tracks were recorded annually on the entire nesting beach on Tromelin, compared with 1480 ± 666 (n = 19) on 16% of nesting beaches on Grande Glorieuse and 1361 ± 903 (n = 23) on 26% of beaches on Europa. The number of tracks has increased significantly on Europa (3% yr–1) and Grande Glorieuse (6% yr–1). The increasing number of nesting turtles illustrates the effectiveness of conservation measures on sites formerly exploited by humans.
Endangered Species Research (1613-4796) (Inter-Research), 2007-08-15 , Vol. 3 , P. 217-227

Droits : 2007 Inter-Research
http://archimer.ifremer.fr/doc/00018/12917/9874.pdf
DOI:10.3354/esr003217
http://archimer.ifremer.fr/doc/00018/12917/

Éditeur(s) : Blackwell science
Résumé : Patterns of mitochondrial DNA (mtDNA) variation were used to analyse the population genetic structure of southwestern Indian Ocean green turtle (Chelonia mydas) populations. Analysis of sequence variation over 396 bp of the mtDNA control region revealed seven haplotypes among 288 individuals from 10 nesting sites in the Southwest Indian Ocean. This is the first time that Atlantic Ocean haplotypes have been recorded among any Indo-Pacific nesting populations. Previous studies indicated that the Cape of Good Hope was a major biogeographical barrier between the Atlantic and Indian Oceans because evidence for gene flow in the last 1.5 million years has yet to emerge. This study, by sampling localities adjacent to this barrier, demonstrates that recent gene flow has occurred from the Atlantic Ocean into the Indian Ocean via the Cape of Good Hope. We also found compelling genetic evidence that green turtles nesting at the rookeries of the South Mozambique Channel (SMC) and those nesting in the North Mozambique Channel (NMC) belong to separate genetic stocks. Furthermore, the SMC could be subdivided in two different genetic stocks, one in Europa and the other one in Juan de Nova. We suggest that this particular genetic pattern along the Mozambique Channel is attributable to a recent colonization from the Atlantic Ocean and is maintained by oceanic conditions in the northern and southern Mozambique Channel that influence early stages in the green turtle life cycle.
Molecular Ecology (0962-1083) (Blackwell science), 2007 , Vol. 16 , N. 1 , P. 175-186

Droits : 2007 Blackwell
http://archimer.ifremer.fr/doc/2007/publication-2185.pdf
DOI:10.1111/j.1365-294X.2006.03122.x
http://archimer.ifremer.fr/doc/00000/2185/