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| Registros recuperados: 97 | |
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| Dhurmeea, Zahirah; Zudaire, Iker; Chassot, Emmanuel; Cedras, Maria; Nikolic, Natacha; Bourjea, Jerome; West, Wendy; Appadoo, Chandani; Bodin, Nathalie. |
| The reproductive biology of albacore tuna, Thunnus alalunga, in the western Indian Ocean was examined through analysis of the sex ratio, spawning season, length-at-maturity (L50), spawning frequency and fecundity. From 2013 to 2015, a total of 923 female and 867 male albacore were sampled. A bias in sex ratio was found in favor of females with fork length (LF) < 100 cm. Using histological analyses and gonadosomatic index, spawning was found to occur between 10°S and 30°S, mainly to the east of Madagascar from October to January. Large females contributed more to reproduction through their longer spawning period compared to small individuals. The L50 (mean ± standard error) of female albacore was estimated at 85.3 ± 0.7 cm LF. Albacore spawn on average... |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00362/47284/47261.pdf |
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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... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00244/35517/34022.pdf |
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| Chavance, Pierre; Chassot, Emmanuel; Bourjea, Jerome; Evano, Hugues; Huet, Jerome; Bach, Pascal; Sabarros, Philippe. |
| Pour ce qui concerne la France (excluant Mayotte), trois flottilles ont des activités de pêche thonière dans l'océan Indien : - les senneurs opérant pour l’essentiel à partir des Seychelles et de l’Ile Maurice, - les palangriers basés à La Réunion, et à un moindre degré la petite pêche réunionnaise. - La flottille thonière française à la senne exerçant dans l’océan Indien atteint 8 navires en 2013 et ses capture se sont élevées à 39 958 tonnes, soit un niveau légèrement supérieur à celui de 2012 (37 155 t) avec une légère augmentation de l’effort de pêche (2 291 jours de pêche en 2013 et 1 944 jours en 2012). Le programme observateur mis en place depuis 2005, qui a permis de fournir les premières évaluations des rejets et des prises accessoires en 2008, a... |
| Tipo: Text |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00239/35015/33552.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; 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... |
| Tipo: Text |
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| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/00244/35516/34021.pdf |
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| Nikolic, Natacha; Fonteneau, Alain; Hoarau, Ludovic; Morandeau, Gilles; Puech, Alexis; Bourjea, Jerome. |
| The most comprehensive contribution to our understanding of albacore tuna, Thunnus alalunga, comes from studies in the Pacific and Atlantic Ocean. In the Indian Ocean, there is little information about this species in the literature. In the present paper, we propose a short review on albacore in the Indian Ocean with a particular attention on the biology, the structure, and the migration. We focused on these fields because they are key components of stock assessment undertaken by the Regional Fishery Management Organization. This work is part of an ongoing work on a global review of albacore tuna in the world. |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00208/31925/30343.pdf |
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| Muths, Delphine; Gouws, G.; Mwale, M.; Tessier, Emmanuel; Bourjea, Jerome. |
| Examining the genetic structure of species allows an estimate of the level of evolutionary connectivity between localities; this information is important for marine biodiversity protection, in particular, for the delineation of marine protected areas. In this context, a total of 601 Lutjanus kasmira (Forsskal, 1775) were sampled in 16 localities of the western Indian Ocean and analyzed with both mitochondrial cytochrome b sequencing and eight microsatellite loci genotyping. Both genetic markers indicate that differentiation was not significant even between samples separated by more than 4000 km. This absence of genetic differentiation among samples was favored by ecological plasticity of the species and is now ensured by resultant high levels of dispersal.... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00079/19044/16647.pdf |
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| Mahe, Kelig; Evano, Hugues; Mille, Tiphaine; Bourjea, Jerome. |
| Swordfish (Xiphias gladius) is an oceanic-pelagic species currently fully exploited by several fisheries in the Indian Ocean, with suspicion of overexploitation in the southwest, but without a clear understanding of the real stock structure within this Ocean. Population structure of the Indian stock was studied in the western Indian Ocean using 395 individual samples collected from 2009 to 2014. Sagittal otoliths of the fish have been removed and shape analysis performed on these calcified pieces. Otolith morphometrics data and normalized Elliptical Fourier Descriptors (EFDs) were then extracted automatically by the dedicated imageanalysis system TNPC. Preliminary, side effect was tested by Redundancy analysis (RDA) combined to permutation tests on 91... |
| Tipo: Text |
Palavras-chave: Xiphias gladius; Otolith shape; Fourier descriptors; Stock discrimination; Indian Ocean. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00269/37980/36068.pdf |
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| Bourjea, Jerome; Frappier, Julie; Quillard, Mireille; Ciccione, Stephane; Roos, David; Hughes, Georges; Grizel, Henri. |
| 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... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00018/12916/9873.pdf |
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| Nikolic, Natacha; Puech, Alexis; Chouvelon, Tiphaine; Munschy, Catherine; Bodin, Nathalie; Brach-papa, Christophe; Potier, Michel; West, Wendy; Knoery, Joel; Zudaire, Iker; Dhurmeea, Zahirah; Degroote, Maxime; Cedras, Maria; Evano, Hugues; Bourjea, Jerome. |
| The GERMON project had several aims i) to understand the populations’ structure between albacore tuna southwest of the Indian Ocean and southeast Atlantic, ii) to determine the origin of juveniles observed in South Africa iii) to improve the understanding of the biology field (Size/Size and Size/Weight; reproduction and feeding area; trophic linkages) and iv) to initiate work on chemical analyzes and adaptation of the albacore species to its environment. These aims have been held and the results allow a better understanding of the management albacore. A general summary of results is presented in Part 9. |
| Tipo: Text |
Palavras-chave: Germon; Thunnus alalunga; Génétique; Stock; Structure; Connectivité; Chimie; Reproduction; Alimentation; Habitat; Albacore; Thunnus alalunga; Genetic; Stock; Structure; Connectivity; Chemical; Reproduction; Feeding behavior; Habitat. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00293/40461/39152.pdf |
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| Bourjea, Jerome; Le Couls, Sarah; Muths, Delphine; Evano, Hugues. |
| Based on genetic and biological dynamic approaches, the main objective of the IOSSSESPADON project (2009-2011) is to study the biology and the stock structure of the Swordfish (Xiphias gladius) in the Indian Ocean and the bordering oceans (South East Atlantic and West Pacific). The results of this project will greatly contribute to a better stock assessment of this species that is undertaken by fisheries management commissions, mainly the IOTC. The first year of the project was dedicated to finalize the sampling strategy, to elaborate the associated protocols and to implement a large balanced sampling shame organised around a stratified spatio – temporal effort (2 sampling seasons: April – June and October – December) in the whole Indian Ocean. Based on a... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00018/12914/9871.pdf |
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| Chavance, Pierre; Chassot, Emmanuel; Bourjea, Jerome; Evano, Hugues; Nadeau, Aurelie; Bach, Pascal; Marsac, Francis; Dagorn, Laurent. |
| Pour ce qui concerne la France (excluant Mayotte), trois flottilles ont des activités de pêche thonière dans l'Océan Indien : (1) les senneurs opérant pour l’essentiel à partir des Seychelles et de l’Ile Maurice, - les palangriers basés à La Réunion, et à un moindre degré la petite pêche réunionnaise. La flottille thonière française à la senne exerçant dans l’océan Indien atteint 10 navires en 2012 et ses capture se sont élevées à 37 155 tonnes, soit un niveau sensiblement inférieur à celui de 2011 (42 894 t) avec une légère diminution de l’effort de pêche (1 944 jours de pêche en 2012 et 2 109 jours en 2011). Le programme observateur mis en place depuis 2005, qui a permis de fournir les premières évaluations des rejets et des prises accessoires en 2008, a... |
| Tipo: Text |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00166/27716/25909.pdf |
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| Bourjea, Jerome. |
| The Areas Beyond National Jurisdiction (ABNJ, or Common Oceans) Tuna Project is a Global Environment Facility (GEF)-funded, FAO-implemented programme of work designed to encourage and reinforce sustainable tuna fisheries. One of the three main components of the project focuses on mitigating bycatch and ameliorating adverse impacts on biodiversity. Taking its cue from a work plan developed by the Joint t-RFMO Technical Working Group- Bycatch, the ABNJ Tuna Project aims to progress prioritized research on sea turtle bycatch mitigation through encouraging data sharing and collaborative analysis (Joint Tuna RFMOs 2011). Funding has been allocated to WCPFC and The Pacific Community (SPC) under the ABNJ work programme to support two sets of workshops on bycatch... |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00366/47693/80260.pdf |
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| Bourjea, Jerome; Dalleau, Mayeul; Derville, S.; Beudard, F.; Marmoex, C.; M'Soili, A.; Roos, David; Ciccione, S.; Frazier, J.. |
| Nesting green turtles Chelonia mydas were studied at Moheli Island, Union of Comoros, southwestern Indian Ocean (SWIO). Five contiguous beaches near Itsamia village, in the southeastern part of the island, were monitored daily for nesting activity from January 1999 to June 2007 and irregularly between August 2009 and December 2014; nesting success was recorded from 2000 to 2006. Nesting occurred year-round and peaked in the austral winter, from March through August, with the highest values in May. During the 7 yr period when nesting success was recorded, 63164 successful nestings were reported, and the total was 69630 when estimates of missing data were included. The average rate of nesting success was 0.49 (SD = 0.04, n = 7). Using the estimate of 3.03... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00266/37733/35745.pdf |
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| Chavance, Pierre; Herfaut, Johanna; Bourjea, Jerome; Chassot, Emmanuel. |
| Les outre-mer français de l’océan indien incluent Mayotte, Département depuis le 31 mars 2011 et les îles Eparses qui sont rattachées à l’administration supérieure des Terres Australes et Antarctiques françaises (TAAF). Depuis janvier 2010, Mayotte dispose d’un parc naturel marin (PNM) doté d’un conseil de gestion dont les limites maritimes sont celles de la ZEE de Mayotte. Un second parc naturel marin a été créé le 22 février 2012 (décret n°2012-245 du 22 février 2012), il s’agit du PNM des Glorieuses, qui dépend des îles Eparses, qui s’étend sur l’ensemble de la ZEE des Glorieuses. Les captures totales dans l’océan Indien des 5 senneurs français immatriculés à Mayotte se sont élevées en 2013 à 26 000 tonnes, soit une diminution de 10% par rapport à 2012... |
| Tipo: Text |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00239/35016/33553.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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| Dhurmeea, Zahirah; Pethybridge, Heidi; Langlais, Clothilde; Somes, Christopher J.; Nikolic, Natacha; Bourjea, Jerome; Appadoo, Chandani; Bodin, Nathalie. |
| Albacore tuna (Thunnus alalunga) is a highly economically important species in the western Indian Ocean. However, knowledge of its ecological and nutritional characteristics, essential for proper management of the species, is lacking in the region. The trophodynamics of the Indian Ocean albacore was thus examined using known fatty acid trophic markers (FATMs) of primary producers, nutritional condition indices (NCIs) (omega-3/omega-6 ratio and total fatty acid content (TFA)), and baseline and lipid corrected stable isotope of carbon (δ13Ccorr) and nitrogen (δ15Ncorr), measured in the muscle tissue. We applied generalized additive mixed models to understand the spatiotemporal patterns and drivers of these tracers, taking into consideration several intrinsic... |
| Tipo: Text |
Palavras-chave: Trophodynamics; Phytoplankton; Environmental parameters; Climate change. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00623/73497/72787.pdf |
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| Registros recuperados: 97 | |
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