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| Registros recuperados: 21 | |
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| Dortel, Emmanuelle; Sardenne, Fany; Bousquet, N.; Rivot, Etienne; Million, Julien; Le Croizier, Gael; Chassot, Emmanuel. |
| The Indian Ocean Tuna Tagging Program provided a unique opportunity to collect demographic data on the key commercially targeted tropical tuna species in the Indian Ocean. In this paper, we focused on estimating growth rates for one of these species, yellowfin (Thunnus albacares). Whilst most growth studies only draw on one data source, in this study we use a range of data sources: individual growth rates derived from yellowfin that were tagged and recaptured, direct age estimates obtained through otolith readings, and length-frequency data collected from the purse seine fishery between 2000 and 2010. To combine these data sources, we used an integrated Bayesian model that allowed us to account for the process and measurement errors associated with each... |
| Tipo: Text |
Palavras-chave: Indian Ocean yellowfin; Hierarchical Bayesian model; Tagging; Fisheries. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00254/36513/35080.pdf |
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| Chassot, Emmanuel; Sabarros, Philippe; Maufroy, A; Ruiz, J; Ramos, Ml; Barreau, E; Barde, Julien. |
| Observations of turtles in the open-ocean are essential to complement the information collected at nesting sites and rookeries, especially during the ‘lost years’ of their surface-pelagic juvenile phase. We used a large dataset of observations at sea collected onboard Seychelles, Spanish and French purse seiners over the period 2003-2019 to describe the occurrence of five species of turtles in the Western Indian Ocean: green ( Chelonia mydas ), loggerhead ( Caretta caretta ), leatherback ( Dermochelys coriacea ), Olive ridley ( Lepidochelys olivacea ) and hawksbill ( Eretmochelys imbricata ). A total of 895 turtles were recorded by human observers, 487 turtles after having been caught in the purse seine and hauled onboard the vessels and 408 turtles... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00599/71131/69446.pdf |
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| Sardenne, Fany; Dortel, Emmanuelle; Le Croizier, Gael; Million, Julien; Labonne, Maylis; Leroy, Bruno; Bodin, Nathalie; Chassot, Emmanuel. |
| The Indian Ocean Tuna Tagging Program (IOTTP) provided a unique opportunity to assess the viability of estimating the age of tropical tunas from the micro-structural features of otoliths. Here, we analyzed the length measurements and micro-increment counts collected for 506 sagittal otoliths, of which 343 were chemically marked with oxytetracycline, for bigeye (Thunnus obesus), skipjack (Katsuwonus pelamis), and yellowfin tuna (Thunnus albacares). Our results show that the otoliths of tropical tunas grow more slowly than the rest of the body. Our findings confirm that both yellowfin and juvenile bigeye deposit daily increments in their otoliths, though ages are underestimated for large bigeye (>100 cm) when derived from micro-increment counts. Our... |
| Tipo: Text |
Palavras-chave: Daily age; Micro-increment; Mark-recapture; Oxytetracycline; Thunnus. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00254/36511/35082.pdf |
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| Bonhommeau, Sylvain; Dubroca, Laurent; Le Pape, Olivier; Barde, Julien; Kaplan, David; Chassot, Emmanuel; Nieblas, Anne-elise. |
| Trophic levels are critical for synthesizing species' diets, depicting energy pathways, understanding food web dynamics and ecosystem functioning, and monitoring ecosystem health. Specifically, trophic levels describe the position of species in a food web, from primary producers to apex predators (range, 1-5). Small differences in trophic level can reflect large differences in diet. Although trophic levels are among the most basic information collected for animals in ecosystems, a human trophic level (HTL) has never been defined. Here, we find a global HTL of 2.21, i.e., the trophic level of anchoveta. This value has increased with time, consistent with the global trend toward diets higher in meat. National HTLs ranging between 2.04 and 2.57 reflect a... |
| Tipo: Text |
Palavras-chave: Human ecology; Nutrition transition; Trophic ecology. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00171/28190/26609.pdf |
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| Marsac, Francis; Chassot, Emmanuel; Cauquil, Pascal; Chavance, Pierre; Clot, Thierry; Bach, Pascal; Bourjea, Jerome; Bodin, Natalie. |
| Depuis le passage de Mayotte comme territoire sous régime communautaire, l’outre-mer français tropical de l’océan Indien ne concerne plus que les îles Eparses qui sont rattachées à l’administration supérieure des Terres Australes et Antarctiques françaises (TAAF). Un parc naturel marin a été créé le 22 février 2012 (décret n°2012-245), il s’agit du PNM des Glorieuses, qui dépend des îles Eparses et s’étend sur l’ensemble de la ZEE des Glorieuses. Les Iles Eparses sont inhabitées et ne disposent pas de flottilles thonières immatriculées à France-Territoires. Néanmoins, les TAAF délivrent des licences de pêche à des palangriers et senneurs français et étrangers souhaitant pêcher dans les eaux françaises, et un programme observateur accompagne l’octroi de ces... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00308/41896/41162.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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| Laurent-monpetit, Christophe; Chavance, Pierre; 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 senneurs français immatriculés à Mayotte se sont élevées en 2011 à 26 610 tonnes, soit une augmentation sensible de 45% par... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00109/21984/19600.pdf |
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| Chassot, Emmanuel; Bonhommeau, Sylvain; Dulvy, Nicholas K.; Melin, Frederic; Watson, Reg; Gascuel, Didier; Le Pape, Olivier. |
| Primary production must constrain the amount of fish and invertebrates available to expanding fisheries; however the degree of limitation has only been demonstrated at regional scales to date. Here we show that phytoplanktonic primary production, estimated from an ocean-colour satellite (SeaWiFS), is related to global fisheries catches at the scale of Large Marine Ecosystems, while accounting for temperature and ecological factors such as ecosystem size and type, species richness, animal body size, and the degree and nature of fisheries exploitation. Indeed we show that global fisheries catches since 1950 have been increasingly constrained by the amount of primary production. The primary production appropriated by current global fisheries is 17-112% higher... |
| Tipo: Text |
Palavras-chave: Bottom-up; Large Marine Ecosystem; Quantile regression; Sustainable fishing. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00002/11294/7836.pdf |
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| Maufroy, Alexandra; Chassot, Emmanuel; Joo, Rocio; Kaplan, David. |
| Since the 1990s, massive use of drifting Fish Aggregating Devices (dFADs) to aggregate tropical tunas has strongly modified global purse-seine fisheries. For the first time, a large data set of GPS positions from buoys deployed by French purse-seiners to monitor dFADs is analysed to provide information on spatio-temporal patterns of dFAD use in the Atlantic and Indian Oceans during 2007-2011. First, we select among four classification methods the model that best separates "at sea" from "on board" buoy positions. A random forest model had the best performance, both in terms of the rate of false "at sea" predictions and the amount of over-segmentation of "at sea" trajectories (i.e., artificial division of trajectories into multiple, shorter pieces due to... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00271/38256/73660.pdf |
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| Imzilen, Taha; Bonhommeau, Sylvain; Rouyer, Tristan; Kell, Laurence T; Chassot, Emmanuel; Barde, Julien. |
| In this note, we present an approach which has been recently used to execute online the set of codes used for eastern blue_n tuna (BFT-E) stock assessment at ICCAT. We aim at discussing the possible interest of the approach to the IOTC Community for focusing on Indian ocean tuna and tuna-like stocks and running other assesment models such as Stock Synthesis 3 (SS3). In 2014, ICCAT BFT-E working group has been able to execute thousands of model runs by using parallelization of R and Fortran codes on a supercomputer. This approach has a lot of scienti_c bene_ts, in particular for better including the multiple sources of uncertainty in assessment results and associated scienti_c advice. However, very few participants would be able to reproduce it without... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00360/47135/47084.pdf |
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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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| Chassot, Emmanuel; Bonhommeau, Sylvain; Reygondeau, Gabriel; Nieto, Karen; Polovina, Jeffrey J.; Huret, Martin; Dulvy, Nicholas K.; Demarcq, Herve. |
| Satellite remote sensing (SRS) of the marine environment has become instrumental in ecology for environmental monitoring and impact assessment, and it is a promising tool for conservation issues. In the context of an ecosystem approach to fisheries management (EAFM), global, daily, systematic, high-resolution images obtained from satellites provide a good data source for incorporating habitat considerations into marine fish population dynamics. An overview of the most common SRS datasets available to fishery scientists and state-of-the-art data-processing methods is presented, focusing on recently developed techniques for detecting mesoscale features such as eddies, fronts, filaments, and river plumes of major importance in productivity enhancement and... |
| Tipo: Text |
Palavras-chave: Ecosystem approach; Fisheries; Mesoscale; Satellite; Tracking. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00031/14188/11468.pdf |
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| Imzilen, Taha; Lett, Christophe; Chassot, Emmanuel; Kaplan, David. |
| Debris from fisheries pose significant threats to coastal marine ecosystems worldwide. Tropical tuna purse seine fisheries contribute to this problem via the construction and deployment of thousands of human-made drifting fish aggregating devices (dFADs) annually, many of which end up beaching in coastal areas. Here, we analyzed approximately 40,000 dFAD trajectories in the Indian Ocean and 12,000 dFAD trajectories in the Atlantic Ocean deployed over the decade 2008–2017 to identify where and when beachings occur. We find that there is tremendous promise for reducing beaching events by prohibiting deployments in areas most likely to lead to a beaching. For example, our results indicate that 21% to 40% (depending on effort redistribution after closure) of... |
| Tipo: Text |
Palavras-chave: Marine pollution; Fishing debris; Coral reefs; Fish aggregating device (FAD); Ocean currents. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00669/78060/80807.pdf |
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| Chassot, Emmanuel; Bodin, Nathalie; Sardenne, Fany; Obura, David. |
| The Northern Mozambique Channel (NMC) is a tropical area of similar to 1 million km(2) where pelagic fisheries supply proteins to more than 9 million people living in Comoros, Mayotte, and along the coasts of Mozambique, Tanzania and Madagascar. Although uncertain, statistics suggest that about 20,000 mt of tropical tuna and other pelagic fish are annually caught by artisanal fisheries in the area. The NMC is also a major seasonal fishing ground for high-seas fleets that export an annual average catch of more than 20,000 mt to tuna can and sashimi markets of high-income countries for a value estimated to be more than 100 million USD. The fisheries productivity of the NMC appears to be highly variable in relation to strong annual and seasonal variability in... |
| Tipo: Text |
Palavras-chave: Bigeye; Fisheries management; Mozambique Channel; Skipjack; Yellowfin. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00512/62366/66661.pdf |
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| Pecoraro, Carlo; Babbucci, Massimiliano; Franch, Rafaella; Rico, Ciro; Papetti, Chiara; Chassot, Emmanuel; Bodin, Nathalie; Cariani, Alessia; Bargelloni, Luca; Tinti, Fausto. |
| Yellowfin tuna, Thunnus albacares, is one of the most important seafood commodities in the world. Despite its great biological and economic importance, conflicting evidence arises from classical genetic and tagging studies concerning the yellowfin tuna population structure at local and global oceanic scales. Access to more powerful and cost effective genetic tools would represent the first step towards resolving the population structure of yellowfin tuna across its distribution range. Using a panel of 939 neutral Single Nucleotide Polymorphisms (SNPs), and the most comprehensive data set of yellowfin samples available so far, we found genetic differentiation among the Atlantic, Indian and Pacific oceans. The genetic stock structure analysis carried out... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00460/57128/75130.pdf |
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| Kaplan, David; Bach, Pascal; Bonhommeau, Sylvain; Chassot, Emmanuel; Chavance, Pierre; Dagorn, Laurent; Davies, Tim; Dueri, Sibylle; Fletcher, Rick; Fonteneau, Alain; Fromentin, Jean-marc; Gaertner, Daniel; Hampton, John; Hilborn, Ray; Hobday, Alistair; Kearney, Robert; Kleiber, Pierre; Lehodey, Patrick; Marsac, Francis; Maury, Olivier; Mees, Chris; Menard, Frederic; Pearce, John; Sibert, John. |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00139/25068/23186.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, trois flottilles ont des activités de pêche thonière dans l'Océan Indien : - les senneurs opérant pour l’essentiel à partir des Seychelles, - 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 2011 et ses capture se sont élevées à 42 900 tonnes, soit un niveau sensiblement inférieur à celui de 2010 (47 000 t) malgré une stabilité de l’effort de pêche (2 109 jours de pêche en 2011 et 2 132 jours en 2010). 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 du être stoppé mi 2009 pour raison de sécurité,... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00109/21983/19599.pdf |
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| Bach, Pascal; Chassot, Emmanuel; Bourjea, Jerome; Evano, Hugues; Huet, Jerome; Chavance, Pierre; Floch, I; Cauquil, Pascal; Sabarros, Phillipe; Giannasi, P; Marsac, Francis. |
| Pour ce qui concerne la France en incluant dorénavant le département de Mayotte, rattaché à la flotte de l’UE depuis le 1er janvier 2014, cinq 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, les palangriers basés à Mayotte, et à un moindre degré les pêches artisanales réunionnaise - La flottille thonière française à la senne exerçant dans l’océan Indien atteint 13 navires en 2014 et ses capture se sont élevées à 58 421 tonnes, soit un niveau largement supérieur à celui de 2013 (39958 t) en lien avec une augmentation de l’effort de pêche de 2 291 jours de pêche en 2013 à 3756 jours en 2014. Le programme... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00308/41893/41160.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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| Registros recuperados: 21 | |
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