Éditeur(s) : HAL CCSD Université des Antilles
Résumé : International audience
Within thirty years, the small island of Saint-Barthelemy (25 km²) is out of its secular isolation to be among major luxury tourism destinations in the world. In this study, the idea is to identify structural element and different cyclical factors that help to understand Saint-Barthelemy tourism situation. The small size of the territory itself can be seen as a fundamental handicap or, conversely, as a considerable asset. Everything depends on development project. It is necessary to know how to take advantage of specific characteristics of this type of territory. In Saint-Barthelemy case, scarcity is coveted; this coveted rarity is accessible only for rich people. The coveted rarity leads to luxury. Isolation is relative: this destination is not accessible to the jumbo jets. The airline market is controlled essentially by two small local companies and the airspace is open to charter flies and private aircrafts. Some other companies provide more or less regular flights from nearby airports of San Juan (Puerto Rico), Sint-Maarten and Guadeloupe. Luxury cannot be decreed, it is not planned. Luxury tourism is the election of a territory by elites who gather there to enjoy away from the rest of the world.
En l’espace de trente ans, la petite île de Saint-Barthélemy (25 km²) est sortie de son isolement séculaire pour s’imposer parmi les grandes destinations du tourisme de luxe dans le monde. Dans le cadre de cette étude, l’idée est d’identifier les éléments structurels et les différents facteurs conjoncturels qui permettent de comprendre la situation touristique de Saint-Barthélemy. L’exiguïté du territoire en lui-même peut être perçue comme un handicap fondamental ou, inversement, comme un atout considérable. Tout dépend du projet de développement. Il faut savoir tirer profit des spécificités du territoire considéré. Dans le cas de Saint-Barthélemy, l’exiguïté favorise la rareté et cette rareté convoitée n’est accessible qu’aux personnes les plus argentées. La rareté convoitée conduit au luxe. L’isolement est relatif : cette destination n’est pas accessible aux avions gros porteurs, l’essentiel du marché aérien est contrôlé par deux petites compagnies locales et l’espace aérien est ouvert aux petits avions privés. Le luxe ne se décrète pas, il ne se planifie pas. Le tourisme de luxe, c’est l’élection d’un territoire par des élites qui s’y retrouvent pour jouir de leur fortune à l’écart du monde.
ISSN: 1779-0980

Droits : http://creativecommons.org/licenses/by-nc/
hal-01364775
https://hal.univ-antilles.fr/hal-01364775
https://hal.univ-antilles.fr/hal-01364775/document
https://hal.univ-antilles.fr/hal-01364775/file/L%27%C3%AEle%20de%20Saint-Barth%C3%A9lemy%20une%20destination%20du%20tourisme%20de%20luxe.pdf
DOI : 10.4000/etudescaribeennes.6831

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999 15-19 octobre 1999
Résumé : Payao is a traditional concept, which has been successfully commercialized to increase the landings of several species valuable to the country's export and local industries. It has become one of the most important developments in pelagic fishing that significantly contributed to increased tuna production and expansion of purse seine and other fishing gears. The introduction of the payao in tuna fishing in 1975 triggered the rapid development of the tuna and small pelagic fishery. With limited management schemes and strategies, however, unstable tuna and tuna-like species production was experienced in the 1980s and 1990s. In this paper, the evolution and development of the payao with emphasis on the technological aspect are reviewed. The present practices and techniques of payao in various parts of the country, including its structure, ownership, distribution, and fishing operations are discussed. Monitoring results of purse seine/ringnet operations including handline using payao in Celebes Sea and Western Luzon are presented to compare fishing styles and techniques, payao designs and species caught. The fishing gears in various regions of the country for harvesting payao are enumerated and discussed. The inshore and offshore payaos in terms of sea depth, location, designs, fishing methods and catch composition are also compared. Fishing companies and fisherfolk associations involved in payao operation are presented to determine extent of utilization and involvement in the municipal and commercial sectors of the fishing industry. The issues and problems concerning the use of payao, and its biological, economic impact as well as management aspect are presented. Recommendations are given for future research and actions.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15284/12670.pdf
http://archimer.ifremer.fr/doc/00042/15284/

Éditeur(s) : HAL CCSD Wiley
Résumé : 1. Trade-offs among functional traits reveal major plant strategies that can give insight into species distributions and ecosystem processes. However, current identification of plant strategies lacks the integration of root structural traits together with leaf and stem traits. 2. We examined correlations among 14 traits representing leaf, stem and woody root tissues. Traits were measured on 1084 individuals representing 758 Neotropical tree species, across 13 sites representative of the environmental variation encompassed by three widespread habitats (seasonally flooded, clay terra firme and white-sand forests) at opposite ends of Amazonia (French Guiana and Peru). 3. Woody root traits were closely aligned with stem traits, but not with leaf traits. Altogether leaf, stem and woody root traits delineated two orthogonal axes of functional trade-offs: a first axis defined by leaf traits, corresponding to a leaf economics spectrum, and a second axis defined by covarying stem and woody root traits, corresponding to a wood economics spectrum. These axes remained consistent when accounting for species evolutionary history with phylogenetically independent contrasts. 4. Despite the strong species turnover across sites, the covariation among root and stem structural traits as well as their orthogonality to leaf traits were strongly consistent across habitats and regions. 5. We conclude that root structural traits mirrored stem traits rather than leaf traits in Neotropical trees. Leaf and wood traits define an integrated whole-plant strategy in lowland South American forests that may contribute to a more complete understanding of plant responses to global changes in both correlative and modelling approaches. We suggest further meta-analyses in expanded environmental and geographic zones to determine the generality of this pattern.
ISSN: 0269-8463

hal-01032415
https://hal.archives-ouvertes.fr/hal-01032415
DOI : 10.1111/j.1365-2435.2012.02020.x

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Bruggemann, J.H. (2016). Phylogenetic relationships within Aglaopheniidae (Cnidaria, Hydrozoa) reveal unexpected generic diversity. — Zoologica Scripta, 45, 103–114. Morphology can be misleading in the representation of phylogenetic relationships, especially in simple organisms like cnidarians and particularly in hydrozoans. These suspension feeders are widely distributed in many marine ecosystems, and the family Aglaopheniidae Marktanner-Turneretscher, 1890 is among the most diverse and visible, especially on tropical coral reefs. The taxonomy of this family is based on morphological characters with emphasis on reproductive structures for the identification of genera. This study is the most comprehensive molecular phylogeny of the Aglaopheniidae to date, including six genera and 38 species, of which 13 were investigated for the first time and sampled on tropical coral reefs throughout the Indo-Pacific region. For newly sampled individuals, we sequenced the 16S rRNA, the nuclear locus comprising the complete ITS1-5.8S rRNA gene-ITS2 and the first intron of the calmodulin nuclear gene. Phylogenetic analyses of the data revealed and confirmed a general polyphyly, or doubtful monophyly, of all sampled genera in tropical regions based on both the mitochondrial and nuclear markers. Our results revealed that several morphological characters used today are unsuited to resolve phylogenetic relationships between species and genera, as well as the high phyletic diversity within this family. Future revision of the classification of this family will require extensive geographic sampling and the use of an integrative approach.
ISSN: 0300-3256

hal-01359414
https://hal.archives-ouvertes.fr/hal-01359414
DOI : 10.1111/zsc.12135

Éditeur(s) : Elsevier Sci Ltd
Résumé : Time-series studies have reported trophic cascades in land, freshwater and marine environments in many geographic areas. However, the spatial extent of habitats, a key metric of ecosystem structure, has not been mapped in these studies. Marine reserves can provide experimental, before-after and inside-outside (control-impacted), situations for assessing the impact of fishing on ecosystems. We mapped seabed habitats and their associated communities (biotopes) in New Zealand's oldest marine reserve for comparison with pre-reserve maps created about 30 years previously. Areas grazed bare by sea urchins were entirely replaced in the centre of the reserve by kelp, or alga turf, an intermediate biotope between heavily grazed encrusting algae and lightly grazed kelp. Urchins declined following increased abundance and body size of spiny (rock) lobsters and fish (especially snapper) in the reserve but maintained bare rock outside. While this gradient in habitat change matched the gradient of predator abundance, it also matched the extent of reef habitat area. Thus the trophic cascade may be influenced by the effect of habitat on the abundance and behavioural interactions of urchins and their predators. Further ecosystem changes may arise should the abundance of mega-predators, such as seals, cetaceans and large sharks, increase in the region; if parasites become pathogenic; and/or when invasive species reach the reserve. No-take marine reserves provide real-world experiments that show the importance of species in food webs, and the consequences of fishing for ecosystems. Because these changes in ecosystem structure may continue, and will vary with environment, climate and species distributions, reserves need to be permanent and replicated geographically. Habitat maps should be produced for all reserves to enable ecological changes in the ecosystem to be spatially quantified. (C) 2012 Elsevier Ltd. All rights reserved.
Biological Conservation (0006-3207) (Elsevier Sci Ltd), 2012-10 , Vol. 155 , P. 193-201

Droits : 2012 Elsevier Ltd. All rights reserved
http://archimer.ifremer.fr/doc/00107/21842/20067.pdf
DOI:10.1016/j.biocon.2012.05.009
http://archimer.ifremer.fr/doc/00107/21842/

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Upper-mantle flow beneath the South Pacific is investigated by analysing shear wave splitting parameters at eight permanent long-period and broad-band seismic stations and 10 broad-band stations deployed in French Polynesia from 2001 to 2005 in the framework of the Polynesian Lithosphere and Upper Mantle Experiment (PLUME). Despite the small number of eventsand the rather poor backazimuthal coverage due to the geographical distribution of the natural seismicity, upper-mantle seismic anisotropy has been detected at all stations except at Tahiti where two permanent stations with 15 yr of data show an apparent isotropy. The median value of fast polarization azimuths (N67.5°W) is parallel to the present Pacific absolute platemotion direction in French Polynesia (APM: N67°W). This suggests that the observed SKS fast polarization directions result mainly from olivine crystal preferred orientations produced by deformation in the sublithospheric mantle due to viscous entrainment by the moving Pacific Plate and preserved in the lithosphere as the plate cools. However, analysis of individualmeasurements highlights variations of splitting parameters with event backazimuth that imply an actual upper-mantle structure more complex than a single anisotropic layer with horizontal fast axis. A forward approach shows that a two-layer structure of anisotropy beneath French Polynesia better explains the splitting observations than a single anisotropic layer. Second ordervariations in the measurements may also indicate the presence of small-scale lateral heterogeneities. The influence of plumes or fracture zones within the studied area does not appear to dominate the large-scale anisotropy pattern but may explain these second-order splitting variations across the network.
ISSN: 0956-540X

hal-01249275
https://hal.archives-ouvertes.fr/hal-01249275
https://hal.archives-ouvertes.fr/hal-01249275/document
https://hal.archives-ouvertes.fr/hal-01249275/file/GJI2007SKS.pdf
DOI : 10.1111/j.1365-246X.2007.03475.x

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : La République des Seychelles constitue un archipel formé de quelque 115 petites îles situées dans l’océan Indien, totalisant 455 km² et s’étendant sur 1 200 km. Les trois plus grandes îles intérieures sont Mahé, Praslin et La Digue qui regroupent 95 % de la population. Les îles des Seychelles offrent en raison de leur situation géographique, de leurs particularités climatiques et de l’attractivité de leurs images de destinations touristiques, la possibilité de pratiquer dans des conditions optimales une grande diversité d’activités de tourisme et de sports de nature tout au long de l’année. Les randonnées pédestre et équestre, le VTT, l’escalade, le surf, la plongée, la voile et le canoë-kayak marquent de leurs empreintes cet archipel. L’objectif de cette réflexion est d'identifier la place des activités de sports de nature dans l’offre touristique des Seychelles et de voir dans quelle mesure elles peuvent contribuer au développement durable de l’île, notamment en tissant des relations avec l’activité économique, la structuration du territoire et la construction identitaire. L’enjeu de développement durable est-il pris en compte par les acteurs seychellois dans le domaine touristique ?
The Republic of Seychelles is made of more than 115 small islands in the Indian Ocean, with 455 km2 of land in a stretch of about 1200 km. The three biggest inner islands are Mahe, Praslin, and La Digue, which include about 95% of the population. The Seychelles islands give the possibility in optimal conditions a vast variety of tourism activities and nature sports all year long, due to their geographical situations, their geomorphological configurations, their climate particularities, and their attractive images of touristic destinations. Walking and equestrian trekking, mountain bike, climbing, surfing, diving, yachting, and canoe-kayaking are some activities available in this insular territory. Because of this exceptional potential, the development of “nature” sports is in the (universe) field of leisure and tourism. The objective of this study is to identify what place “nature” sport activities play in the tourism offer in the Seychelles. Don’t they contribute, in the long-term development of the islands by having relations more interactive with the economic activity, the territorial structure, and the identity construction? Is the outcome of long-term development taken seriously by the actors of Seychelles in tourism field?
Seychelles

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.5642
http://journals.openedition.org/etudescaribeennes/5642

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : The EUNIS (European Union Nature Information System) habitat classification system aims to provide a common European reference set of habitat types within a hierarchical classification, and to cover all terrestrial, freshwater and marine habitats of Europe. The classification facilitates reporting of habitat data in a comparable manner, for use in nature conservation (e.g. inventories, monitoring and assessments), habitat mapping and environmental management. For the marine environment the importance of a univocal habitat classification system is confirmed by the fact that many European initiatives, aimed at marine mapping, assessment and reporting, are increasingly using EUNIS habitat categories and respective codes. For this reason substantial efforts have been made to include information on marine benthic habitats from different regions, aiming to provide a comprehensive geographical coverage of European seas. However, there still remain many concerns on its applicability as only a small fraction of Europe's seas are fully mapped and increasing knowledge and application raise further issues to be resolved. This paper presents an overview of the main discussion and conclusions of a workshop, organised by the MeshAtlantic project, focusing upon the experience in using the EUNIS habitats classification across different countries and seas, together with case studies. The aims of the meeting were to: (i) bring together scientists with exper_ience_in the use of the EUNIS marine classification and representatives from the European Environment Agency (EEA); (ii) agree on enhancements to EUNIS that ensure an improved representation of the European marine habitats; and (iii) establish practices that make marine habitat maps produced by scientists more consistent with the needs of managers and decision-makers. During the workshop challenges for the future development of EUNIS were identified, which have been classified into five categories: (1) structure and hierarchy; (2) biology; (3) terminology; (4) mapping; and (5) future development. The workshop ended with a declaration from the attendees, with recommendations to the EEA and European Topic Centre on Biological Diversity, to take into account the outputs of the workshop, which identify weaknesses in the current classification and include proposals for its modification, and to devise a process to further develop the marine component of the EUNIS habitat classification. (C) 2012 Elsevier Ltd. All rights reserved.
Marine Pollution Bulletin (0025-326X) (Pergamon-elsevier Science Ltd), 2012-12 , Vol. 64 , N. 12 , P. 2630-2638

Droits : 2012 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00125/23663/22686.pdf
DOI:10.1016/j.marpolbul.2012.10.010
http://archimer.ifremer.fr/doc/00125/23663/

Éditeur(s) : HAL CCSD IRD
Résumé : International audience
The number of satellites and remote sensing sensors devoted to earth observation becomes increasingly high, providing more and more data and especially images. In the same time the access to such a data and to the tools to process them has been considerably improved. In the presence of such data flow - and regarding the necessity to follow up and predict environmental and societal changes in highly dynamic socio-environmental contexts - we need automatic image interpretation methods. This could be accomplished by exploring some strengths of artificial intelligence. Our main idea consists in inducing classification rules that explicitly take into account structural knowledge, using Aleph, an Inductive Logic Programming (ILP) system. We applied our proposed methodology to three land cover/use maps of the French Guiana littoral. One hundred and forty six classification rules were induced for the 39 land-cover classes of the maps. These rules are expressed in first order logic language which make them intelligible and interpretable by non-experts. A ten-fold cross validation gave average values for classification accuracy, specificity and sensibility equal to, respectively, 98.82 %, 99.65% and 70%. The proposed methodology could be valuably exploited to automatically classify new objects and/or help operators using object-based classification procedures.
Symposium of the Latin American Society for Remote Sensing and Spatial Information Systems (SELPER)
Cayenne, French Guiana

ird-00797337
http://hal.ird.fr/ird-00797337
http://hal.ird.fr/ird-00797337/document
http://hal.ird.fr/ird-00797337/file/Bayoudh_et_al_2012_FP_SELPER-086.pdf
IRD : fdi:010058343

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Fishing with a beach seine for catching small pelagic fishes is a traditional activity in Martinique. Since the early eighties, an important decrease in the number of fishermen practising this activity has been recorded. In the context of high exploitation of reef resources, the beach seine presents a low selectivity, catching too many juveniles of demersal fish. The fads established in coastal areas, have been successfully used in others regions of the world for exploiting small pelagics. Thus, it could allow to favour a change of exploitation style of these resources in Martinique. In partnership, Ifremer, the Regional Council and the Fishing Committee have began an evaluation of the potentialities for this type of structures around the island. To achieve this study, several experimental coastal fads have been established in different places. Surveys by subaquatic observations are periodically carried out to compare the attractive power of different aggregation devices (colour, shape, volume) and understand the factors influencing the determinism of the aggregation (biotic and abiotic). The results presented and discussed correspond to the initial stage of this study which should be pursued in the next months.Original Abstract: La peche a la senne de plage pour la capture des petits poissons pelagiques est une activite halieutique traditionnelle et ancienne en Martinique. Depuis le debut des annees quatre-vingt, une diminution importante du nombre de pecheurs pratiquant cette activite est enregistree. Les dispositifs de concentration de poissons (DCP) implantes en zone cotiere sont abondamment utilises dans d'autres regions du monde avec succes. Ils pourraient donc permettre de redynamiser ce secteur en Martinique. L'Ifremer, le conseil regional et le comite des peches ont entrepris, en partenariat, une etude permettant d'evaluer les potentialites du developpement de ce type d'amenagement autour de l'ile. Pour realiser cette etude, plusieurs DCP cotiers experimentaux ont ete implantes dans differents sites. Ils font l'objet d'un suivi halieutique base sur les comparaisons des captures realisees par les professionnels sur et hors DCP. En parallele, des campagnes d'observations sous-marines sont effectuees de facon periodique. Elles permettent d'une part de comparer les pouvoirs attractifs de differents dispositifs d'agregation (forme, volume, couleur) et, d'autre part, de mieux comprendre les facteurs biotiques et abiotiques influencant le determinisme de l'agregation. Les resultats presentes et discutes correspondent a la phase initiale de l'etude qui doit se poursuivre dans les prochains mois afin de couvrir toute la saison de peche.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15302/12634.pdf
http://archimer.ifremer.fr/doc/00042/15302/

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
ABSTRACT: BACKGROUND: Climate change poses unprecedented challenges, ranging from global and local policy challenges to personal and social action. Heat-related deaths are largely preventable, but interventions for the most vulnerable populations need improvement. Therefore, the prior identification of high risk areas at the community level is required to better inform planning and prevention. We aimed to demonstrate a simple and flexible conceptual framework relying upon satellite thermal data and other digital data with the goal of easily reproducing this framework in a variety of urban configurations. RESULTS: The study area encompasses Rennes, a medium-sized French city. A Landsat ETM + image (60 m resolution) acquired during a localized heatwave (June 2001) was used to estimate land surface temperature (LST) and derive a hazard index. A land-use regression model was performed to predict the LST. Vulnerability was assessed through census data describing four dimensions (socio-economic status, extreme age, population density and building obsolescence). Then, hazard and vulnerability indices were combined to deliver a heatwave health risk index. The LST patterns were quite heterogeneous, reflecting the land cover mosaic inside the city boundary, with hotspots of elevated temperature mainly observed in the city center. A spatial error regression model was highly predictive of the spatial variation in the LST (R2 = 0.87) and was parsimonious. Three land cover descriptors (NDVI, vegetation and water fractions) were negatively linked with the LST. A sensitivity analysis (based on an image acquired on July 2000) yielded similar results. Southern areas exhibited the most vulnerability, although some pockets of higher vulnerability were observed northeast and west of the city. The heatwave health risk map showed evidence of infra-city spatial clustering, with the highest risks observed in a north--south central band. Another sensitivity analysis gave a very high correlation between 2000 and 2001 risk indices (r = 0.98, p < 10-12). CONCLUSIONS: Building on previous work, we developed a reproducible method that can provide guidance for local planners in developing more efficient climate impact adaptations. We recommend, however, using the health risk index together with hazard and vulnerability indices to implement tailored programs because exposure to heat and vulnerability do not require the same prevention strategies.
ISSN: 1476-072X

inserm-00762303
http://www.hal.inserm.fr/inserm-00762303
http://www.hal.inserm.fr/inserm-00762303/document
http://www.hal.inserm.fr/inserm-00762303/file/1476-072X-11-38.pdf
DOI : 10.1186/1476-072X-11-38

Éditeur(s) : Institut national agronomique Paris Grignon
Résumé : The flat oyster Ostrea edulis L. is the indigenous oyster of the Atlantic as well as the Mediterranean coasts of Europe. Its commercial exploitation dates back to Antiquity but its breeding is now threatened by two parasitic protozoa, among which Bonamia ostreae. Various aspects of the genetics of this species' natural and farmed populations have been studied with the aid of microsatellite markers. At first, the implementation and the screening of two partial genomic libraries made it possible to identify 28 new microsatellite loci. Analysis of the segregation of 12 of these loci and of two enzymatic loci shows that most microsatellite loci are transmitted in a Mendelian way, but some loci have significant segregation distortions. Moreover, seven linkage groups, of which four contain at least two markers, were identified in Ostrea edulis. The genetic variability of three populations selected for one or two generations for resistance to Bonamia ostreae was analysed with the aid of 5 microsatellite loci. In spite of the absence of genealogical data, we have shown that these selected populations were descended from a very low number of founding genitors (from 3 to 15 depending on the population) and for two populations, we were able to reconstruct the genealogy and the relationships between the individuals were identified. These selected populations have, in addition to a very low genetic variability, real and at times high levels of consanguinity. These results have a significant implication for the continuation of the selection programme (consanguinity management, augmentation of genetic variability by introducing wild genitors). The geographical structuring of the genetic variability of natural populations of Ostrea edulis has been analysed with the aid of 5 microsatellite loci on a sampling covering almost the entire distribution area of the species (from Norway to the Adriatic Sea). The results are consistent with those published in the literature and using enzymatic markers. The populations show a low level of differentiation that could correspond to a model of isolation by distance. The Atlantic populations, which have a reduced polymorphism, could be descended from post-glacial recolonisation from Mediterranean populations that had survived the glaciations of the Quaternary Period. The current distribution of flat oyster populations is surely also subject to anthropogenic activities. Finally, the genetic bases of the heterozygosis-growth correlation were studied in a natural population with the aid of enzymatic and microsatellite markers. Although leads favouring the direct contribution of enzymatic loci have been found, biases in the sampling design make it impossible to come to a formal conclusion. However, this study has made it possible to show that the capture of individuals over a short period (around ten days) leads to a sampling of a population descended from a very low number of founding genitors, in contradiction with the generally accepted idea that marine bivalve populations are large panmictic populations with significant, efficient numbers. These results confirm in a natural population the observations of a significant reduction of efficient sizes in hatchery populations.
L'huître plate Ostrea edulis L. est l'huître indigène des côtes européennes aussi bien atlantiques que méditerranéennes. Son exploitation commerciale remonte à l'Antiquité mais son élevage est aujourd'hui menacé par deux protozoaires parasites dont Bonamia ostreae. Différents aspects de la génétique des populations naturelles et cultivées de cette espèce ont été étudiés à l'aide de marqueurs microsatellites. Dans un premier temps, la réalisation et le criblage de deux banques génomiques partielles ont permis l'identification de 28 nouveaux locus microsatellites. L'analyse de la ségrégation de 12 de ces locus et de deux locus enzymatiques montre que la plupart des locus microsatellites sont transmis de façon mendélienne, mais certains locus présentent des distorsions de ségrégation importantes. Par ailleurs, sept groupes de liaison dont quatre contiennent au moins deux marqueurs ont été identifiés chez Ostrea edulis. La variabilité génétique de trois populations sélectionnées depuis une ou deux générations pour une résistance à Bonamia ostreae a été analysée à l'aide de 5 locus microsatellites. Malgré l'absence de données généalogiques, nous avons montré que ces populations sélectionnées étaient issues d'un très faible nombre de géniteurs fondateurs (de 3 à 15 selon les populations) et pour deux populations, la généalogie a pu être reconstituée et les liens de parenté entre les individus ont été identifiés. Ces populations sélectionnées présentent, outre une très faible variabilité génétique, des niveaux de consanguinité réels et parfois élevés. Ces résultats ont une implication importante pour la continuation du programme de sélection (gestion de la consanguinité, augmentation de la variabilité génétique par introduction de géniteurs sauvages). La structuration géographique de la variabilité génétique des populations naturelles d'Ostrea edulis a été analysée à l'aide de 5 locus microsatellites sur un échantillonnage couvrant presque toute l'aire de répartition de l'espèce (de la Norvège à la Mer Adriatique). Les résultats sont cohérents avec ceux publiés dans la littérature et utilisant des marqueurs enzymatiques. Les populations montrent un niveau de différenciation faible qui pourrait correspondre à un modèle d'isolement par la distance. Les populations atlantiques, qui présentent un polymorphisme réduit, pourraient être issues de recolonisation post-glaciaire à partir de populations méditerranéennes ayant survécu aux glaciations du Quaternaire. La répartition actuelle des populations d'huître plate est certainement aussi soumise aux actions anthropiques. Enfin, les bases génétiques de la corrélation hétérozygotie-croissance ont été étudiées dans une population naturelle à l'aide de marqueurs enzymatiques et microsatellites. Bien que des pistes en faveur de la contribution directe des locus enzymatiques aient été trouvées, des biais dans le dispositif expérimental ne permettent pas de conclure de façon formelle. Cependant, cette étude a permis de montrer que le captage d'individus sur une faible période (une dizaine de jours) conduit à l'échantillonnage d'une population issue d'un nombre très réduit de géniteurs fondateurs, en contradiction avec l'idée reçue que les populations de bivalves marins sont de larges populations panmictiques à effectif efficace important. Ces résultats confirment dans une population naturelle les observations de réduction importante des tailles efficaces dans des populations d'écloserie.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1998/these-1919.pdf
http://archimer.ifremer.fr/doc/00000/1919/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Background : Biological communities are normally composed of a few abundant and many rare species. This pattern is particularly prominent in microbial communities, in which most constituent taxa are usually extremely rare. Although abundant and rare subcommunities may present intrinsic characteristics that could be crucial for understanding community dynamics and ecosystem functioning, microbiologists normally do not differentiate between them. Here, we investigate abundant and rare subcommunities of marine microbial eukaryotes, a crucial group of organisms that remains among the least-explored biodiversity components of the biosphere. We surveyed surface waters of six separate coastal locations in Europe, independently considering the picoplankton, nanoplankton, and microplankton/mesoplankton organismal size fractions.Results : Deep Illumina sequencing of the 18S rRNA indicated that the abundant regional community was mostly structured by organismal size fraction, whereas the rare regional community was mainly structured by geographic origin. However, some abundant and rare taxa presented similar biogeography, pointing to spatiotemporal structure in the rare microeukaryote biosphere. Abundant and rare subcommunities presented regular proportions across samples, indicating similar species-abundance distributions despite taxonomic compositional variation. Several taxa were abundant in one location and rare in other locations, suggesting large oscillations in abundance. The substantial amount of metabolically active lineages found in the rare biosphere suggests that this subcommunity constitutes a diversity reservoir that can respond rapidly to environmental change.Conclusions : We propose that marine planktonic microeukaryote assemblages incorporate dynamic and metabolically active abundant and rare subcommunities, with contrasting structuring patterns but fairly regular proportions, across space and time.
ISSN: 0960-9822

hal-01149637
http://hal.upmc.fr/hal-01149637
http://hal.upmc.fr/hal-01149637/document
http://hal.upmc.fr/hal-01149637/file/Logares_et_al_CurrentBiol_accepted.pdf
DOI : 10.1016/j.cub.2014.02.050

Résumé : Les méthodes classiques d'analyse d'images satellites sont inadaptées au volume actuel du flux de données. L'automatisation de l'interprétation de ces images devient donc cruciale pour l'analyse et la gestion des phénomènes observables par satellite et évoluant dans le temps et l'espace. Ce travail vise à automatiser la cartographie dynamique de l'occupation du sol à partir d'images satellites, par des mécanismes expressifs, facilement interprétables en prenant en compte les aspects structurels de l'information géographique. Il s'inscrit dans le cadre de l'analyse d'images basée objet. Ainsi, un paramétrage supervisé d'un algorithme de segmentation d'images est proposé. Dans un deuxième temps, une méthode de classification supervisée d'objets géographiques est présentée combinant apprentissage automatique par programmation logique inductive et classement par l'approche multi-class rule set intersection. Ces approches sont appliquées à la cartographie de la bande côtière Guyanaise. Les résultats démontrent la faisabilité du paramétrage de la segmentation, mais également sa variabilité en fonction des classes de la carte de référence et des données d'entrée. Les résultats de la classification supervisée montrent qu'il est possible d'induire des règles de classification expressives, véhiculant des informations cohérentes et structurelles dans un contexte applicatif donnée et conduisant à des valeurs satisfaisantes de précision et de KAPPA (respectivement 84,6% et 0,7). Ce travail de thèse contribue ainsi à l'automatisation de la cartographie dynamique à partir d'images de télédétection et propose des perspectives originales et prometteuses.
Classical methods for satellite image analysis are inadequate for the current bulky data flow. Thus, automate the interpretation of such images becomes crucial for the analysis and management of phenomena changing in time and space, observable by satellite. Thus, this work aims at automating land cover cartography from satellite images, by expressive and easily interpretable mechanism, and by explicitly taking into account structural aspects of geographic information. It is part of the object-based image analysis framework, and assumes that it is possible to extract useful contextual knowledge from maps. Thus, a supervised parameterization methods of a segmentation algorithm is proposed. Secondly, a supervised classification of geographical objects is presented. It combines machine learning by inductive logic programming and the multi-class rule set intersection approach. These approaches are applied to the French Guiana coastline cartography. The results demonstrate the feasibility of the segmentation parameterization, but also its variability as a function of the reference map classes and of the input data. Yet, methodological developments allow to consider an operational implementation of such an approach. The results of the object supervised classification show that it is possible to induce expressive classification rules that convey consistent and structural information in a given application context and lead to reliable predictions, with overall accuracy and Kappa values equal to, respectively, 84,6% and 0,7. In conclusion, this work contributes to the automation of the dynamic cartography from remotely sensed images and proposes original and promising perpectives

http://www.theses.fr/2013AGUY0671/document

Éditeur(s) : EDP Sciences
Résumé : Selective fishing pressure on more highly valued marine living resources is one of the key factors proposed to explain changes occurring in fish communities and associated landings of commercial fisheries. The aim of this paper is to establish the nature of changes in the landings of French fishing fleets operating in the Bay of Biscay in the period 1973-2002, and whether these changes could be related to the relative economic attractiveness of different fish species. The analysis focuses on trends observed in the landings of all commercial fish species over the last three decades. It is based on data of annual quantities landed and ex-vessel prices compiled from official French landings records, and on bio-geographical descriptors of these species derived from published data. Using simple index numbers and multivariate analysis, we examined changes in total landings in terms of their volume and value, as well as changes in their composition. We show that the composition of landings significantly changed over the study period, with an increase in the proportion of pelagic species, of lower economic value. The average ex-vessel price of production by the fleets tended to decrease from the late 1980s; partly due to a cross-species drop in prices, occurring mainly after 1993, but also to the increased proportion of low-priced species in the landings. This caused a significant drop in the total gross value of production in the second half of the study period.
La pression de pêche sélective sur les ressources marines vivantes de forte valeur est un des facteurs-clés proposés pour expliquer les changements qui surviennent dans la structure des communautés de poisson et dans les débarquements des pêcheries commerciales associés. L'objectif de cet article est d'établir la nature des changements dans les débarquements des flottilles de pêche françaises opérant dans le golfe de Gascogne, et d'examiner les relations entre ces changements et l'attractivité relative des espèces de poisson d'un point de vue économique. L'analyse se concentre sur les tendances observées au cours des trois dernières décennies dans les débarquements de toutes les espèces commerciales de poissons effectués par les flottilles de pêche opérant dans le golfe. Elle s'appuie sur des données concernant les quantités annuelles débarquées, les prix compilés à partir des enregistrements officiels des débarquements français, et les données publiées concernant les caractéristiques biogéographiques des espèces étudiées. En s'appuyant sur des indices simples et une analyse multivariée, on examine les changements des débarquements totaux en volume et en valeur, ainsi que les changements dans leur composition. On montre que la composition des débarquements a fortement changé au cours de la période étudiée, avec un accroissement important de la part des espèces pélagiques, de plus faible valeur. Le prix moyen de la production a eu tendance à décroître depuis la fin des années 1980. Ceci est en partie dû à une chute des prix de l'ensemble des espèces, après 1993, et en partie lié à l'accroissement de la part des espèces de plus faible valeur dans les débarquements. Une baisse importante de la valeur de la production en a découlé sur cette deuxième moitié de la période d'étude.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2008-07 , Vol. 21 , N. 3 , P. 317-327

Droits : 2008 EDP Sciences
http://archimer.ifremer.fr/doc/2008/publication-5926.pdf
DOI:10.1051/alr:2008048
http://archimer.ifremer.fr/doc/00000/5926/

Éditeur(s) : Wiley-blackwell
Résumé : In bird species that have a high movement capacity, dispersal may connect subpopulations over vast geographical regions, with important consequences for the design of conservation management strategies. Here we used a molecular approach to infer the patterns and rates of dispersal among eight Mediterranean subpopulations of the endangered Bonelli's Eagle, based on 245 individuals screened at 17 microsatellite loci. There was moderate genetic differentiation between subpopulations sampled in the western (Iberia and Morocco) and eastern (Cyprus) Mediterranean, whereas differentiation among subpopulations in the former region was weak to moderate and followed a pattern of isolation by distance. Within the western Mediterranean, the small, peripheral and ecologically unique population of southwest Portugal had the lowest genetic diversity and the highest differentiation. The remaining subpopulations formed two loose clusters, one including Morocco and southwest and eastern Spain, and the other northeast Portugal and western and central Spain. Few recent migrants were detected, and they originated primarily from adjacent subpopulations. Our findings suggest that western Mediterranean Bonelli's Eagles may have a large-scale metapopulation structure, with subpopulations connected to some extent by distance-dependent dispersal, probably influenced by natal philopatry and the geographical configuration of subpopulations. The combination of marked ecological and genetic divergence suggests that the peripheral subpopulation of southwest Portugal may be regarded as a distinct management unit.
Ibis (0019-1019) (Wiley-blackwell), 2013-07 , Vol. 155 , N. 3 , P. 485-498

Droits : 2013 British Ornithologists’ Union
http://archimer.ifremer.fr/doc/00148/25924/24018.pdf
DOI:10.1111/ibi.12065
http://archimer.ifremer.fr/doc/00148/25924/

Éditeur(s) : HAL CCSD Inter-Research
Résumé : International audience
Many large groupers form spawning aggregations, returning to the same spawning sites in consecutive spawning seasons. Connectivity between spawning aggregations is thus assured by larval dispersal. This study looks into the genetic structure and gene flow among spawning aggregations of a large grouper, the gulf coney Hyporthodus acanthistius, in the northern Gulf of California. First, using the mitochondrial control region and 11 microsatellites, we calculated FST metrics and conducted a Bayesian clustering analysis to determine structure among 5 spawning aggregations. Shallow genetic structure was found, separating the southernmost spawning aggregate from the remainder. Second, we used the results from the structure analysis and local water circulation patterns to delineate 3 distinct models of gene flow. The best-supported model, in which the southernmost spawning aggregate formed one group and all other spawning aggregates were nested into a second group, was the one that was consistent with water circulation during the species’ spawning season. Larval retention within a seasonal anticyclonic gyre that formed during the gulf coney’s spawning season may be responsible for the patterns found. This study highlights the importance of local oceanographic conditions in dictating the structure among spawning aggregations even at small geographic scales and contributes to informed management plans for this overexploited grouper.
Marine Ecology Progress Series

hal-01301199
https://hal-univ-perp.archives-ouvertes.fr/hal-01301199
DOI : 10.3354/meps10637

Éditeur(s) : Wiley-blackwell
Résumé : The history of colonization and dispersal in fauna distributed among deep-sea chemosynthetic ecosystems remains enigmatic and poorly understood because of an inability to mark and track individuals. A combination of molecular, morphological and environmental data improves understanding of spatial and temporal scales at which panmixia, disruption of gene flow or even speciation may occur. Vestimentiferan tubeworms of the genus Escarpia are important components of deep -sea cold seep ecosystems, as they provide long-term habitat for many other taxa. Three species of Escarpia, Escarpia spicata [Gulf of California (GoC)], Escarpia laminata [Gulf of Mexico (GoM)] and Escarpia southwardae (West African Cold Seeps), have been described based on morphology, but are not discriminated through the use of mitochondrial markers (cytochrome oxidase subunit 1; large ribosomal subunit rDNA, 16S; cytochrome b). Here, we also sequenced the exon-primed intron-crossing Haemoglobin subunit B2 intron and genotyped 28 microsatellites to (i) determine the level of genetic differentiation, if any, among the three geographically separated entities and (ii) identify possible population structure at the regional scale within the GoM and West Africa. Results at the global scale support the occurrence of three genetically distinct groups. At the regional scale among eight sampling sites of E. laminata (n=129) and among three sampling sites of E. southwardae (n=80), no population structure was detected. These findings suggest that despite the patchiness and isolation of seep habitats, connectivity is high on regional scales.
Molecular Ecology (0962-1083) (Wiley-blackwell), 2013-08 , Vol. 22 , N. 16 , P. 4147-4162

Droits : 2013 John Wiley & Sons Ltd
http://archimer.ifremer.fr/doc/00152/26354/24515.pdf
DOI:10.1111/mec.12379
http://archimer.ifremer.fr/doc/00152/26354/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The number of satellites and sensors devoted to Earth observation has become increasingly elevated, delivering extensive data, especially images. At the same time, the access to such data and the tools needed to process them has considerably improved. In the presence of such data flow, we need automatic image interpretation methods, especially when it comes to the monitoring and prediction of environmental and societal changes in highly dynamic socio-environmental contexts. This could be accomplished via artificial intelligence. The concept described here relies on the induction of classification rules that explicitly take into account structural knowledge, using Aleph, an Inductive Logic Programming (ILP) system, combined with a multi-class classification procedure. This methodology was used to monitor changes in land cover/use of the French Guiana coastline. One hundred and fifty-eight classification rules were induced from 3 diachronic land cover/use maps including 38 classes. These rules were expressed in first order logic language, which makes them easily understandable by non-experts. A 10-fold cross-validation gave significant average values of 84.62%, 99.57% and 77.22% for classification accuracy, specificity and sensitivity, respectively. Our methodology could be beneficial to automatically classify new objects and to facilitate object-based classification procedures.
ISSN: 0098-3004

hal-01369822
https://hal.archives-ouvertes.fr/hal-01369822
https://hal.archives-ouvertes.fr/hal-01369822/document
https://hal.archives-ouvertes.fr/hal-01369822/file/CAGEO-D-13-00538R1_article.pdf
DOI : 10.1016/j.cageo.2014.08.013

Éditeur(s) : Amer Meteorological Soc
Résumé : The Congo River has the second largest rate of flow in the world and is mainly responsible for the broad tongue of low-salinity water that is observed in the Gulf of Guinea. Despite their importance, near-equatorial river plumes have not been studied as thoroughly as midlatitude plumes and their dynamics remain unclear. Using both theory and idealized numerical experiments that reproduce the major characteristics of the region, the authors have investigated the dynamics of the Congo River plume and examine its sensitivity to different forcing mechanisms. It is found that near-equatorial plumes are more likely to be surface trapped than midlatitude plumes, and the importance of the effect in describing the strong offshore extent of the low-salinity tongue during most of the year is demonstrated. It is shown that the buoyant plume constrained by the geomorphology is subject to the pulling of nonlinear structures and wavelike equatorial dynamics. The wind is found to strengthen the intrinsic buoyancy-driven dynamics and impede the development of the coastal southward current, in coherence with observations.
Journal Of Physical Oceanography (0022-3670) (Amer Meteorological Soc), 2014-03 , Vol. 44 , N. 3 , P. 980-994

Droits : 2014 American Meteorological Society
http://archimer.ifremer.fr/doc/00187/29850/28298.pdf
DOI:10.1175/JPO-D-13-0132.1
http://archimer.ifremer.fr/doc/00187/29850/