Éditeur(s) : CARDI : Caribbean Agricultural Rechearch and Development Institute Université des Antilles. Service commun de la documentation
Extrait de : 52e congrès annuel de la Société caribéenne des plantes alimentaires / 52nd annual meeting of the Caribbean food crops society (CFCS), du 10 au 16 juillet 2016. INRA, CFCS
Description : Banana and plantain (Musa spp) are important foreign exchange earners in Guyana and the Windward Islands of the Caribbean. Black Sigatoka Disease (BSD) also referred to as black leaf streak disease is one of the most destructive diseases of banana and plantain and is present within the region. In Guyana within two years following its introduction in 2008, the industry was totally decimated, recording a 100% decline, turning the country to a net banana importer. Also, from 2009 ? 2012 the disease spread in the Windward Islands causing as much as 100% decrease in the export of banana. The disease is caused by the ascomycete fungus, Mycosphaerella fijiensis (anamorph Pseudocercospora fijiensis) and is aggressive, challenging to control and results in enormous crop damage if left uncontrolled. In an effort to develop an integrated management approach to the disease the Caribbean Agricultural Research and Development Institute (CARDI) with financial assistance from the Caribbean Development Bank (CDB) is evaluating five FHIA banana and plantain accessions and eight IITA plantain accessions for tolerance to BSD. The evaluation is presently conducted in four Caribbean countries, Dominica, Guyana, St Lucia and St Vincent and the Grenadines. In each country, four distinct agro- ecological zones were selected for the trial evaluation blocks and using a randomized block design, four blocks were established in each country. Five FHIA accessions: FHIA-01, FHIA-03, FHIA-18, FHIA-21 and FHIA-23 are being evaluated in Dominica, St Lucia and St Vincent and the Grenadines whereas, plantain accessions: PITA-17, PITA-21, PITA-22, PITA-23, PITA-24 and PITA-26 are to be evaluated in Guyana for tolerance to the disease. Cavendish are used as regional controls and as borders rows to increase disease pressure. The disease parameters evaluated are youngest leaf spotted (YLS), disease development time (DDT), leaf emission rate (LER), disease severity at 6 months, bunch emergence and harvest, and index of standing leaves. Agronomic data; days from planting to flowering, bunch weight, number of hands in bunch, average weight of hands and average number of fingers per hand and bunch, as well as organoleptic characteristics of both cooked and ripe fruits are also evaluated. The early data collection, of the FHIA only accessions, show trends in the disease tolerance and agronomic performance as well as their adaptability in the different agro-ecological zone. The trends indicate better disease tolerance of FHIA varieties with higher leaf counts before, at bunching and at harvest. The organoleptic test shows a preference to FHIA 03 and FHIA 21. La banane et le plantain (espèces de Musa) sont les acquéreurs de devises étrangères importants en Guyane et en Îles du Vent des Caraïbe. La maladie noire de Sigatoka (schéma) également désignée sous le nom de la maladie noire de filet de feuille est l'une des maladies les plus destructives de la banane et du plantain et est présente dans la région. En Guyane dans un délai de deux ans après son introduction en 2008, l'industrie a été totalement décimée, enregistrant une baisse de 100%, tournant le pays à un importateur net de banane. En outre, à partir de 2009-2012 la propagation de maladie en Îles du Vent causant pas moins de la diminution de 100% de l'exportation de la banane. La maladie est provoquée par le champignon d'ascomycète, fijiensis de Mycosphaerella (fijiensis anamorph de Pseudocercospora) et est agressive, contestant pour commander et les résultats dans l'énorme culture endommagent si laissé incontrôlé. Dans un effort de développer une approche intégrée de gestion à la maladie l'institut agricole des Caraïbes de recherche et développement (CARDI) avec l'aide financière de la banque de développement des Caraïbes (BDC) évalue des adhésions de banane et de plantain de cinq FHIA et huit adhésions de plantain d'IITA pour la tolérance au schéma. L'évaluation est actuellement effectuée quatre pays des Caraïbes, Dominique, Guyane, St Lucia et Saint-Vincent-et-les Grenadines. Dans chaque pays, quatre agro zones écologiques distinctes ont été sélectionnées pour les blocs d'essai d'évaluation et employant une conception de bloc randomisé, quatre blocs ont été établis dans chaque pays. Cinq adhésions de FHIA : FHIA-01, FHIA-03, FHIA-18, FHIA-21 et FHIA-23 sont évalués en Dominique, au St Lucia et au Saint-Vincent-et-les Grenadines tandis que, des adhésions de plantain : PITA-17, PITA-21, PITA-22, PITA-23, PITA-24 et PITA-26 doivent être évalués en Guyane pour la tolérance à la maladie. Cavendish sont employés en tant que contrôles régionaux et comme rangées de frontières pour augmenter la pression de la maladie. Les paramètres de la maladie évalués sont la plus jeune feuille repérée (YLS), le temps d'élaboration de la maladie (DDT), le taux d'émission de feuille (LER), la sévérité de la maladie à 6 mois, émergences et récoltes de groupe, et index des feuilles debout. Données agronomiques ; des jours de la plantation à la floraison, du poids de groupe, nombre de mains dans le poids de groupe et moyen des mains et du nombre moyen de doigts par main et groupe, aussi bien que les caractéristiques organoleptiques des fruits cuits et mûrs sont également évalués. La collecte de données tôt, des adhésions de FHIA seulement, exposition tend dans la tolérance de maladie et la représentation agronomique aussi bien que leur adaptabilité dans la zone agro-écologique différente. Les tendances indiquent qu'une meilleure tolérance de maladie des variétés de FHIA avec une plus haute feuille compte avant, à se rassembler et à la récolte. L'essai organoleptique montre une préférence à FHIA 03 et à FHIA 21.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V16266
V16266

Éditeur(s) : INRA : Institut National de la Recherche Agronomique Université des Antilles. Service commun de la documentation University of Suriname
Extrait de : 52e congrès annuel de la Société caribéenne des plantes alimentaires / 52nd annual meeting of the Caribbean food crops society (CFCS), du 10 au 16 juillet 2016. INRA, CFCS
Description : Many rural areas in Suriname are lacking information on technology from extension agents from the government extension agency, and research institutes. Communication and informal voices of farmers are shared by media. As part of a baseline study conducted for the sixth operational strategic plan of the Small Grants Programme in Suriname, four communities were selected: Moengo, Pokigron, Nickerie, Sipaliwini and Para. The purpose of this study was to collect data from communities regarding problems related to climate change, agricultural innovation and landscape management. This qualitative study was done through the focus group method. Eight focus group meetings were organized and consisted of 8-15 participants each. The key questions were extracted from the SEPLS method (Socio-ecological Production Landscapes and Seascapes). The data was analyzed through the SWOT method. Based on the results, the communities have a good level of awareness about management of their landscapes. Improvement of agriculture management will be possible by access to innovative and new knowledge developed in and outside the community. Climate change is an important issue that the community already is aware of, they developed their own local strategy in resilience to this issue. Beaucoup de zones rurales au Surinam manquent d'information sur la technologie des agents de vulgarisation de l'agence d'extension de gouvernement, et des instituts de recherche. La communication et les voix informelles des agriculteurs sont partagées par media. En tant qu'élément d'une étude de ligne de base entreprise pour le sixième plan stratégique opérationnel du petit programme de concessions au Surinam, les quatre communautés ont été sélectionnées : Moengo, Pokigron, Nickerie, Sipaliwini et paragraphe. Le but de cette étude était de rassembler des données de communautés concernant des problèmes liés au changement climatique, à l'innovation agricole et à la gestion de paysage. Cette étude qualitative a été faite par la méthode de groupe cible. Huit réunions de groupe cible ont été organisées et se sont composées de 8-15 participants chacun. Les questions clé ont été extraites à partir de la méthode de SEPLS (des paysages et des paysages marins Socio-écologiques de production). Les données ont été analysées par la méthode de BÛCHEUR. Basé sur les résultats, les communautés ont un bon niveau de conscience au sujet de la gestion de leurs paysages. L'amélioration de la gestion d'agriculture sera possible par l'accès aux connaissances innovatrices et nouvelles développées à l'intérieur et à l'extérieur de la communauté. Le changement climatique est une question importante que la communauté a pris en compte et développé sa propre stratégie locale dans la résilience.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V16256
V16256

Éditeur(s) : HAL CCSD
Résumé : International audience
Many countries are legally obliged to embrace ecosystem-based approaches to fisheries management. Reductions in bycatch and physical habitat damage are now commonplace, but mitigating more sophisticated impacts associated with the ecological functions of target fisheries species are in their infancy. Here we model the impacts of a parrotfish fishery on the future state and resilience of Caribbean coral reefs, enabling us to view the tradeoff between harvest and ecosystem health. We find that the implementation of a simple and enforceable size restriction of >30 cm provides a win:win outcome in the short term, delivering both ecological and fisheries benefits and leading to increased yield and greater coral recovery rate for a given harvest rate. However, maintaining resilient coral reefs even until 2030 requires the addition of harvest limitations (<10% of virgin fishable biomass) to cope with a changing climate and induced coral disturbances, even in reefs that are relatively healthy today. Managing parrotfish is not a panacea for protecting coral reefs but can play a role in sustaining the health of reefs and high-quality habitat for reef fisheries.
http://hal.univ-reunion.fr/hal-01369752

hal-01369752
http://hal.univ-reunion.fr/hal-01369752
DOI : 10.1073/pnas.1601529113

Éditeur(s) : Yale University
Résumé : Sea-surface temperature images of the coastal upwelling regions off Northwest Africa show that the core of upwelling is sometimes located far from the coast. This has been documented in three regions that share a common feature, namely a wide and shallow continental shelf. This upwelling feature plays a key role in the ecology of the Canary Current System. It creates an innerfront which provides retention for biological material, e.g. fish eggs and larvae, in the highly productive nearshore environment. An analytical model has been developed based on a two dimensional extension of Ekman's solution. The linear and steady response of a homogeneous ocean forced by an upwelling-favorable wind provides a mechanism for the upwelling separation from the coast. The merging of the surface and bottom Ekman layers induces a very weak cross-shore circulation and a "kinematic barrier" for the Ekman transport divergence. In the case of an alongshore wind, the barrier is located near the isobath h ≈ 0.4D, where D is the thickness of Ekman layers. This yields an upwelling cell which is essentially concentrated in the region 0.5D < h < 1.25D, with upwelling occurring preferentially near the isobath h ≈ 0.6D. It turns out that the cross-shore width of upwelling scales with D/S, the ratio of Ekman depth to bottom topographic slope. The application of this solution to real bathymetric profiles rationalizes, not only the offshore upwelling observations in Northwest Africa, but also the influence of topography on the cross-shelf structure of a wind-driven coastal upwelling. The model also quantifies the effect of the cross-shore wind component showing how it drives the nearshore pressure gradient adjustment and how it affects the upwelling. A linear numerical experiment reproduces the theoretical steady solution, thereby allowing investigation of the transient regime. Relaxation of the hypothesis in the numerical model validates the linear assumption of the theory and then allows investigation of the sensitivity to friction parameterizations and the influence of stratification. The latter leads to an "oscillation" of the upwelling cell with seaward migration driven by outcropping and homogeneization of the water column, and, coastal incursion driven by a "boundary layers splitting" process caused by shoreward advection of the isopycnal dome and stratification of the inner shelf.
Journal of Marine Research (Yale University), 2008-09 , Vol. 66 , N. 5 , P. 589-616

Droits : 2008 Yale University
http://archimer.ifremer.fr/doc/2008/publication-6334.pdf
DOI:10.1357/002224008787536790
http://archimer.ifremer.fr/doc/00000/6334/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
29 inorganic compounds (Al, As, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Fe, Gd, K, Mg, Mn, Mo, Na, Nd, Ni, Pb, Sb, Se, Sr, Ti, U, V and Zn) were measured in the tap water of 484 representative homes of children aged 6 months to 6 years in metropolitan France in 2008-2009. Parents were asked whether their children consumed tap water. Sampling design and sampling weights were taken into account to estimate element concentrations in tap water supplied to the 3,581,991 homes of 4,923,058 children aged 6 months to 6 years. Median and 95th percentiles of concentrations in tap water were in mu g/L: Al: <10, 483, As: 02, 2.1; B: <100, 100; Ba: 30.7, 149.4; Ca: 85,000, 121,700; Cd: <0.5, <0.5; Ce: <0.5, <0.5; Co: <0.5, 0.8; Cr: <5, <5; Cu: 70, 720; K: 2210, 6740; Fe: <20, 46; Mn: <5, <5; Mo: <0.5,1.5; Na: 14,500, 66,800; Ni: <2,10.2; Mg: 6500,21,200; Pb: <1, 5.4; Sb: <0.5, <0.5; Se: <1, 6.7; Sr: 256.9, 1004; TI: <0.5, <0.5; U: <0.5, 2.4; V: <1, 1; Zn; 53, 208. Of the 2,977,123 young children drinking tap water in France, some were drinking water having concentrations above the 2011 World Health Organization drinking water quality guidelines: respectively 498 (CI 95%: 0-1484) over 700 mu g/L of Ba; 121,581 (CI 95%: 7091-236,070) over 50 mg/L of Na; 2044 (CI 95%: 0-6132) over 70 mu g/L of Ni, and 78,466 (17,171-139,761) over 10 mu g/L of Pb. Since it is representative, this tap water contamination data can be used for integrated exposure assessment, in conjunction with diet and environmental (dust and soil) exposure data. (C) 2016 Elsevier Ltd. All rights reserved.
ISSN: 0160-4120

hal-01390976
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01390976
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01390976/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01390976/file/Le%20Bot%202016%20EI%20revision1%20.pdf
DOI : 10.1016/j.envint.2016.06.009

Éditeur(s) : ICCAT
Résumé : The present working document aims to list the main environmental databases (including in-situ observations, remote-sensing data and ocean models outputs), that are currently available on the Net and of interest in open-sea fisheries biology and ecology.
Ce document a pour objet de lister les principales bases de données environnementales (concernant les données in-situ, satellitaires et les sorties de modèles océaniques), qui sont actuellement disponibles sur la toile et d’intérêt pour l’écologie halieutique se rapportant aux ressources thonières.
El objetivo de este documento es presentar una relación de las principales bases de datos medioambientales (sobre datos in situ, vía satélite y valores de salida de los modelos oceánicos) que están disponibles actualmente en la red y que revisten interés para la ecología pesquera relacionada con los recursos atuneros.
Collective Volume of Scientific Papers (1021-5212) (ICCAT), 2005 , Vol. 58 , N. 5 , P. 1756-1760

Droits : ICCAT
http://archimer.ifremer.fr/doc/00194/30501/28911.pdf
http://archimer.ifremer.fr/doc/00194/30501/

Éditeur(s) : EDP Sciences
Résumé : The WFD monitoring requirements for surface waters were adapted to the coastal area with the selection of the relevant parameters to qualify the maritime ecosystems, with appropriate strategies of sampling. Ifremer and Cemagref for the fish indicator in the estuarine waters, are in charge of the elaboration of the monitoring programme in coastal waters (surveillance monitoring and operational monitoring). Ifremer has elaborated technical recommendations for the monitoring of the biological (benthic and phytoplanctonic) and chemical elements, according to many years of observations by the french monitoring networks (RNO, Rephy, Rinbio, RSL, Rebent). These recommendations were established within experts groups They clarify the parameters, the analytical methods, and the strategies of sampling for the classification of the water bodies in five ecological classes and two chemical classes. The work on the relevant indicators of the ecological status still goes on, in relation with the 2006 european intercalibration exercise. Available data and future data will be used in order to set the borders between the classes of high, good, and moderate status, before the monitoring programme starts. Data sets have to be completed to set the borders and to assess the ecological status of water bodies.
Houille Blanche - Revue internationale de l'eau (0018-6368) (EDP Sciences), 2006-07 , N. 4 , P. 68-74

Droits : © Société Hydrotechnique de France 2006
http://archimer.ifremer.fr/doc/2006/publication-3530.pdf
DOI:10.1051/lhb:200604011
http://archimer.ifremer.fr/doc/00000/3530/

Résumé : After a period of rapid development of the sites (an increase in both reared surface area and production), tropical shrimp aquaculture is currently being faced with critical problems due to economical and ecological constraints. In many countries with favourable conditions for shrimp aquaculture such as indonesia or Vietnam, sites are often badly selected and/or over-exploited. This conducts to sorne extent to decreases or collapses in the production due to the difficulty in predicting the maximum production capacity of the sites. Furthermore, it appears that production sustainability depends on many factors among which socio-economy and ecolo gy are of prime importance. The STD3 project titled « Assessment of tropical shrimp aquaculture impact on the environment in tropical countries using hydrobiology, ecology and remote sensing as helping tools for diagnosis )) was initiated in 1994, with the aim to study the sustainability of marine shrimp aquaculture in tropical areas, main! y Indonesia and Vietnam, through the following tasks: (i) improve site selection and study the impact of aquaculture on marine environments presenting a variable sensitivity to organic sewage, (ii) analyse the socio-economical aspects and profitability of the aquaculture industry and of common resources (iii) use remote sensing and geographical data bases for diagnosis and monitoring of site degradation (iv) reinforce the capacity of Asian scientists through training. Severa! aquaculture sites have been investigated in the Lampung region (South Sumatra, Indonesia), the Mekong delta (Vietnam) and on the West coast of New-Caledonia, providing a large range of typical ecosystems encountered in Asia and in the Pacifie, from coralline sites to coastal plains with mangrove and deltaic areas. The study concerned the spatial structure and seasonal influence of these ecosystems, the temporal variation during the course of the project (3 years) and the relation between the ecological structure and farm productions. Remote sensing provides a synoptic vision over large land expanses. Severa! scenes were processed for landuse mapping using conventional classification techniques. Concerning water quality assessment, a general relation for the Java sea was found between image and field data in terms of total suspended matter. Applying this relation to a new site in Sumatra has provided an initial approach to water type and, together with land use mapping, a preliminary assessment of the suitability of the area to shrimp aquaculture development. Socio-economic research has been focused on the identification ofneeds for collective action, including public policy, in the perspective of shrimp farming sustainability. The main concern is in the regulation of shrimp farming intensification and extensification at the scale of coastal ecosystemic entities in a common property resource management perspective. The common considered here is coastal water quality. Comparing the local development profiles and the institutional grounds for the design and implementation of collective management rules shows that variables such as land tenure system, farm owner socio-economic profile, social homogeneity or heterogeneity of the farmers are key factors to analyse the potential for sustainability. The defmition of water quality and the possible means to ensure its collective management are discussed. The main conclusion is that the economie incentives to farming development are strong but there is no significant difference among traditional, semi-intensive and intensive systems in terms of economie efficiency or wealth distribution. The description of the functioning of the different kinds of ecosystems make it possible to give an advice concerning the positioning of the activity inside the ecosystem, and furthermore to have a reference state in order to determine the impact of the activity on the coastal environnement. This impact can be summarized as an increase in the concentration of total suspended matt€?r, of particulate organic matter and of sulfate reducing bacterias. This organic ma~.er is either issued from rearing activities or from telluric origine, due to mangrove eradication when building the ponds. An evaluation of the relationship existing between productivity and characteristics of each ecosystem bas been conducted by correlating ecological indicators data (concentration of total suspended matter, particulate organic matter, chlorophyll, percentage of pheopigments in total pigments and cyanobacteria and sulfatereducing bacteria in water and sediments) with the average production of the farms. This comparison lead to the compilation of a scale of observed production integrating the range of these environmental parameters with shrimp production levels, bound to facilitate the positioning of shrimp farming in relation with the confmement leve! of each ecosystem. Lastly, ali geographie data originated from the various compartments of the study have been geo-referenced and loaded into a geographical information system. This allows to display any query made on spatial variables and their related statistical data, including the ir variations over the last few years and to reveal patterns and phenomena otherwise not obvious.
Le programme mis en oeuvre par la DRV (Paris, CREMA-L'Houmeau, DELIAO Brest, COP Tahiti, GIE/RA Nouvelle Calédonie), dans le cadre d'un projet européen STD3 «(Sciences et Technique au Service du Développement», en collaboration avec l'Université de Montpellier II, l'Ecole Nationale d'Agronomie de Rennes, l'ITC (Hollande), l'Institut Océanographique de Nha Trang (Vietnam), le BADC de Jepara et le BPPT de Jakarta (Indonésie), avait pour but la mise au point de méthodes permettant d'améliorer la sélection des sites ainsi que le suivi du développement et de l'impact de l'aquaculture des crevettes Péneides en milieu tropical pour éviter la surexploitation. Quatre axes de recherche ont été défmis : a) identifier la nature et quantifier les rejets de déchets issus de ce type d'aquaculture, b) définir les caractéristiques écologiques des écosystèmes susceptibles d'accueillir l'activité aquacole et suivre leur évolution sous l'influence des rejets, c) déterminer l'influence de la gestion des fermes et des ressources (aspects économiques) sur les performances de productivité, d) déterminer la capacité de la télédétection comme outil de diagnostic d'impact à l'échelle de la région, e) mener un programme de formation d'étudiants et jeunes chercheurs Vietnamiens et Indonésiens.

Droits : 1998 Ifremer
http://archimer.ifremer.fr/doc/00132/24357/22357.pdf
http://archimer.ifremer.fr/doc/00132/24357/

Éditeur(s) : Ecole nationale supérieure agronomique de Rennes
Résumé : Describe and gain understanding on fluctuations in animal population over time and space is a central goal of population ecology. This is also crucial to ensure the sustainable management of exploited resources, particularly those with complex population dynamics such as the bluefin tuna. The goal of this work is to collect bluefin tuna catches from the ancestral Mediterranean and Atlantic trap fisheries to (i) characterise long-term fluctuations in bluefin tuna population migrating in the Mediterranean, (ii) analyse their causes et (iii) assess their implications for fisheries management. The bluefin tuna main biological and ecological characteristics are first detailed. Then, the first part presents the trap fishery, and the process of collect and validation of the historical catches. This leads to develop a data base of 54 time-series more than 20 years long, the longest ones spanning about four centuries. Mean historical catches were around 15 000 tons/year ([7 000;25 000]). Time-series are analysed in a second part. Temporal variability of trap catches may be decomposed in three components: 100-year-long periodic fluctuations, 20-year cycles and inter-annual variations. These medium- to long-term fluctuations, representing more than 50% of the variability in the time-series, were synchronous all around the western Mediterranean and adjacent North Atlantic. In contrast, short-term variability was synchronous at a local scale only. It is argued that long-term fluctuations in trap catches could be considered as a proxy for those in abundance, and a synthetic time-series is computed to depict them. Biological and ecological processes that could cause such long-term fluctuations are discussed in a third part. We tested whether long-term fluctuations in Atlantic bluefin tuna might be related to large-scale environmental changes, using long time-series of the North Atlantic Oscillation (NAO), the Length of the Day index (LOD, a proxy of the atmospheric circulation index ACI) and the temperature. Spectral analyses of trap catches, LOD and temperature displayed similar spectra with peak at low frequency, whereas those of the NAO exhibited a broad band spectrum. Regression analyses and tests of correlation did not reveal any clear relationship between trap catches on the one hand and NAO and LOD on the other hand. In contrast, long-term fluctuations in trap catches appear to be negatively and significantly related to long-term trends in temperature. Underlying processes that could explain such a relationship are discussed, with special focus on changes in migration patterns. Finally, implications of such fluctuations in term of fisheries management are discussed in a fourth part. A simulation framework, in which a simulated population dynamics model is coupled with a VPA, is built to test the pertinence of the diagnostic of stock assessment according to different scenarios on fluctuations origins and population status. In the hypothesis of fluctuations linked to variations in the recruitment, VPA appears able to reconstruct the fluctuations but the predictions may be biased if natural fluctuations are not taking into account. In the hypothesis of fluctuations linked to changes in migration pattern, VPA is not able to reconstruct the population dynamics. In a precautionary approach, quotas which follow may be unsuitable in the best case, at worst dangerous if they are defined in comparison with a reference point. The concept of cible reference points, fixe and unique over time, appears not relevant for bluefin tuna; estimate trajectory reference pertinent may prove to be more pertinent.
Décrire et comprendre les fluctuations spatio-temporelles des espèces animales constituent les enjeux majeurs de l'écologie. La question est également cruciale pour réussir la gestion durable des ressources exploitées, en particulier celle du thon rouge, grand pélagique migrateur à la dynamique complexe. L'objectif de ce travail est de collecter les captures historiques de thon rouge par les madragues méditerranéennes et proche atlantiques pour (i) caractériser les fluctuations à long terme de la population migrante en Méditerranée, (ii) étudier leur déterminisme et (iii) évaluer leurs implications en terme de gestion des pêcheries. Après avoir décrit les principales caractéristiques biologiques et écologiques du thon rouge, la première partie présente la pêcherie à la madrague, puis le processus de collecte et de validation des données historiques de captures. Ce dernier conduit à la mise en place d'une base de données de 54 séries de plus de 20 ans, dont les plus longues s'étendent sur près de 4 siècles. Les productions historiques sont estimées à environ 15 000 tonnes/an ([7 000;25 000]). Les séries historiques de captures sont analysées dans la seconde partie. Leur variabilité temporelle peut être décomposée en trois composantes : de larges cycles pseudo-séculaires, des variations périodiques d'une vingtaine d'années et des fluctuations inter-annuelles. Les fluctuations à moyen et long terme, expliquant plus de la moitié de la variance des séries, sont synchrones à l'échelle du bassin méditerranéen occidental et du proche Atlantique. La variabilité inter-annuelle, en revanche, n'est synchrone qu'à une échelle locale. On montre finalement que les fluctuations à long terme des captures peuvent être considérées comme de bons indices des tendances des abondances de la population de thons rouges migrants en Méditerranée. Une série synthétique est construite pour les décrire. Les processus biologiques et écologiques susceptibles d'être à l'origine de ces fluctuations sont discutés dans la troisième partie. L'hypothèse d'un forçage environnemental à grande échelle est testée en utilisant des indices à long terme de l'Oscillation Nord Atlantique (NAO), de la longueur du jour (LOD, un indicateur de l'indice de circulation atmosphérique ACI) et de la température. Les analyses spectrales sur les séries de captures, du LOD et des températures révèlent des spectres similaires, avec un pic sur les basses fréquences, alors que celles sur le NAO conduisent à une large bande spectrale. Les régressions et les tests de corrélations ne montrent aucune relation significative entre les captures par les madragues et le NAO et le LOD. En revanche, les fluctuations à long terme des captures apparaissent significativement et négativement corrélées avec les fluctuations à long terme des températures. Les processus sous-jacents susceptibles d'expliquer une telle relation, en particulier des changements migratoires, sont discutés. Finalement, les implications des fluctuations pour la gestion de la pêcherie sont discutées dans une quatrième partie. Un cadre de simulation, couplant un modèle de dynamique de population à une VPA, est élaboré pour tester la pertinence des diagnostics d'évaluation de stock selon différents scénarios d'origine des fluctuations et d'état de la population. Dans l'hypothèse de fluctuations liées à des variations du recrutement, la VPA apparaît capable de reconstruire les fluctuations mais les prédictions sont biaisées lorsqu'il n'est pas tenu compte des fluctuations naturelles du stock. Dans l'hypothèse de fluctuations liées à des changements migratoires, la VPA est alors incapable de reproduire la dynamique de la population. Dans une approche de précaution, les quotas qui en découlent peuvent se révéler au mieux inappropriés, au pire dangereux s'ils sont définis par rapport à un point de référence. Ce concept de point cible, fixe et unique dans le temps, apparaît inapproprié pour le thon rouge ; estimer des "trajectoires de référence" serait sans doute plus pertinent.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2003/these-65.pdf
http://archimer.ifremer.fr/doc/00000/65/

Éditeur(s) : Université des Antilles et de la Guyane
Résumé : The need for an integrated approach to fisheries is now widely affirmed, including the FAO, in particular in the context of tropical artisanal fisheries. These small-scale fisheries, often multispecies are very important in terms of production, employment and food security. However these fisheries and the exploited resources are often characterized by a lack of data making difficult their management within an ecosystem approach, and by the ecological and economic system complexities including trophic and technological interactions. This thesis aims to contribute to the development of bioeconomic tools for small tropical fisheries in a sustainable management perspective based on the ecosystem approach. In this perspective, the French Guiana coastal fishery constitutes an interesting case study. The thesis proposes multi-criteria evaluations, complex bioeconomic models and viable management scenarios for this fishery. At first, multivariate statistical analysis suggests a satisfactory overall status of the fishery in terms of sustainability. However, some performance differences are noted within the fishery, particularly at border areas. Also, management improvements are proposed. Then, through bioeconomic modeling, projections of different fishing scenarios show that, in the long-term, the current exploitation level may not be consistent with the future increase of local demand and a loss of biodiversity may occur. A scenario called "co-viability" reconciling ecological, economic and social objectives, with a high probability of achievement is exhibited. Finally, the comparison of optimal behavior in cooperative and non-cooperative conditions, confirms that harvest levels are greater when actors do not cooperate. Furthermore, it is shown that the state of the ecosystem depends on the fishing strategies and the type of interaction between species. Beyond the diagnosis made for the case study, the method is promising in the context of small tropical fisheries, while the co-viability approach allows finding the exploitation conditions under which ecological and socio-economic sustainability are meet, what the conventional fisheries management generally do not allow.
La nécessité d’une approche intégrée des pêches est actuellement largement affirmée, notamment par la FAO, en particulier dans le contexte des pêcheries artisanales tropicales. Ces pêcheries à petites échelles, souvent multi-spécifiques sont très importantes en termes d’emploi et de production, y compris pour la sécurité alimentaire. Néanmoins ces pêcheries et la biodiversité exploitées sont souvent marquées, d’une part, par le manque de données rendant difficile leur gestion dans le cadre d’une approche écosystémique, d’autre part, par la complexité des systèmes écologiques et économiques sous-jacents incluant interactions trophiques et techniques. Cette thèse contribue à la mise au point d’outils bioéconomiques adaptés aux petites pêcheries tropicales dans la perspective d’une gestion durable des pêches fondée sur l’approche écosystémique. Dans cette perspective, la pêcherie côtière en Guyane Française constitue un cas d’étude particulièrement fécond. La thèse propose ainsi des évaluations multi-critères, des modèles bioéconomiques complexes et des scénarios de gestion viable pour cette pêcherie. Dans un premier temps l’analyse statistique multivariée suggère un statut global satisfaisant de la pêcherie en termes de durabilité. Cependant des différences de performance sont notées au sein de la pêcherie, notamment au niveau des zones frontalières. Aussi des améliorations dans le mode de gestion sont proposées. Ensuite, à travers la modélisation bioéconomique, les projections des différents scénarios de pêche montrent qu’à long terme le niveau d’exploitation actuel peut ne pas être en adéquation avec la future augmentation de la demande locale et qu’une perte de biodiversité peut avoir lieu. Un scenario dit de "co-viabilité" conciliant des objectifs à la fois écologique, économique et social, avec une probabilité de réalisation satisfaisante, est mis en exergue. Enfin, la comparaison des comportements optimaux en situation coopératif et non coopératif, montre dans quelle mesure la viabilité est favorisée quand les acteurs coopèrent. Au-delà du diagnostic apporté pour le cas d’étude, la méthode utilisée s’avère prometteuse dans le contexte des petites pêcheries tropicales, tandis que l’approche de co-viabilité permet de trouver les modalités d’exploitation dans le cadre de compromis entre durabilité écologique et socio-économique, ce que les principes de gestion halieutiques traditionnels ne permettent généralement pas.

Droits : 2013 Université des Antilles et de la Guyane
http://archimer.ifremer.fr/doc/00144/25492/23646.pdf
http://archimer.ifremer.fr/doc/00144/25492/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : This paper discusses the hypothesis that small tunas and the various species found in association with drifting fads (such as "mahi-mahi", rainbow runner, wahoo, etc.) may be biologically trapped by such a strong association. Massive seeding of drifting artificial fads was observed worldwide during recent years. In this hypothesis, we suggest that fads may alter some biological characteristics of epipelagic populations associated with them: migration, growth, condition factors, predation and natural mortality. As fads are most often used in the equatorial currents, they tend to exhibit zonal drift. Therefore, the associated populations would be artificially transferred from one part of the ocean to another, when they would show different movement patterns in the absence of fads. Natural logs were probably beneficial in terms of ecology and evolution, because they tend to accumulate in convergence areas, most often considered as rich forage areas. Now, fads are seeded in offshore areas, which are not necessarily favourable for tuna feeding. This apparently strong association between fishes and drifting fads may then produce an unexpected biological impact on tuna populations and their associated fauna. The plan is to test this hypothesis in the Atlantic, developing an ad hoc research programme based on tagging, biological and physiological studies, in association to an analysis of high resolution fishery data before and after the development of the fad fishery.Original Abstract: Cet article discute l'hypothese selon laquelle les petits thons et les differentes especes associees a des DCP derivants (comme les coryphenes, elagatis, thazards, etc.) pourraient etre pris dans un piege biologique resultant de cette forte association. Le deploiement massif de DCP artificiels derivants a ete constate a l'echelle mondiale au cours des dernieres annees. Dans cette hypothese, ces DCP, colonises en permanence par de grandes fractions de populations epipelagiques, pourraient modifier les caracteristiques biologiques des especes concernees: leur migration, leur croissance, leurs facteurs de condition, la predation et la mortalite naturelle. Les DCP etant plus frequemment utilises dans les courants equatoriaux, ils tendent a deriver zonalement. Ainsi, les populations associees seraient artificiellement transferees d'un bord a l'autre de l'ocean, alors qu'elles manifesteraient d'autres types de deplacements en l'absence de DCP. Les debris naturels etaient probablement benefiques sur le plan de l'ecologie et de l'evolution car ils s'accumulent dans des zones de convergence le plus souvent considerees comme des zones riches en nourriture. Maintenant, les DCP sont mouilles au large, dans des zones qui peuvent ou non etre favorables a l'alimentation des thons. Cette association apparemment forte entre poissons et DCP derivants pourrait alors causer un impact biologique inattendu sur les populations pelagiques (thons et faune accompagnante). L'objectif est de tester cette hypothese dans l'Atlantique au moyen d'un programme de recherche s'appuyant sur du marquage et des etudes biologiques et physiologiques, parallelement a une analyse des donnees de peche (tailles et CPUE, avant et apres le deploiement des DCP derivants).

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15303/12636.pdf
http://archimer.ifremer.fr/doc/00042/15303/

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: Sampling design is a key issue when establishing species inventories and characterizing habitats within highly heterogeneous landscapes. Sampling efforts in such environments may be constrained and many field studies only rely on subjective and/or qualitative approaches to design collection strategy. The region of Cacao, in French Guiana, provides an excellent study site to understand the presence and abundance of Anopheles mosquitoes, their species dynamics and the transmission risk of malaria across various environments. We propose an objective methodology to define a stratified sampling design. Following thorough environmental characterization, a factorial analysis of mixed groups allows the data to be reduced and non-collinear principal components to be identified while balancing the influences of the different environmental factors. Such components defined new variables which could then be used in a robust k-means clustering procedure. Then, we identified five clusters that corresponded to our sampling strata and selected sampling sites in each stratum. RESULTS: We validated our method by comparing the species overlap of entomological collections from selected sites and the environmental similarities of the same sites. The Morisita index was significantly correlated (Pearson linear correlation) with environmental similarity based on i) the balanced environmental variable groups considered jointly (p = 0.001) and ii) land cover/use (p-value<0.001). The Jaccard index was significantly correlated with land cover/use-based environmental similarity (p-value = 0.001). CONCLUSIONS: The results validate our sampling approach. Land cover/use maps (based on high spatial resolution satellite images) were shown to be particularly useful when studying the presence, density and diversity of Anopheles mosquitoes at local scales and in very heterogeneous landscapes.
BMC Ecology

pasteur-00914104
https://hal-riip.archives-ouvertes.fr/pasteur-00914104
https://hal-riip.archives-ouvertes.fr/pasteur-00914104/document
DOI : 10.1186/1472-6785-13-45
PUBMED : 24289184

Éditeur(s) : Wiley-blackwell
Résumé : 1. Abiotic and biotic variables of coastal lagoons are highly heterogeneous in both space and time, and this heterogeneity complicates the assessment of their ecological status. These variables are essential to the monitoring and preservation of these fragile ecotones and the resources and services they sustain. 2. An integrative approach for evaluating the ecological status of coastal lagoons, based on field investigations of the key parameters driving their functioning and a set of selected ecological indicators matching lagoon management information needs for societal benefits, is investigated. Consistency in lagoon status evaluation from multiple and different variables was estimated, through a case study comparing three adjacent yet contrasting French Mediterranean shallow water lagoons. 3. French Mediterranean shallow water lagoons are used to demonstrate the potential of such an approach and to underline the need for a multi-faceted framework, for correctly evaluating lagoon status, and underlining the need for high-frequency lagoon monitoring to avoid errors in status assessment and resulting management plans. 4. Based on the results, a continuous monitoring system is proposed that would record high frequency biotic and abiotic data in the lagoons. The use of such an ad hoc observatory system, based on appropriate diagnostic indicators and risk estimators would simplify interactions between scientists and managers and would improve the efficiency of their analyses. 5. A lagoon management plan based on a holistic approach is proposed to help scientists and local managers to reach a consensus about the set of ecological indicators to monitor in the lagoons needed to assess their global health status in accordance with both conservation and/or societal needs. Copyright (c) 2011 John Wiley & Sons, Ltd.
Aquatic Conservation-marine And Freshwater Ecosystems (1052-7613) (Wiley-blackwell), 2011-11 , Vol. 21 , N. 7 , P. 728-742

Droits : 2011 John Wiley & Sons, Ltd.
http://archimer.ifremer.fr/doc/00056/16702/14202.pdf
DOI:10.1002/aqc.1231
http://archimer.ifremer.fr/doc/00056/16702/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Tuna world fisheries yield 3 million tons per year; the increase rate of whole production is constant and sustained since 30 years. This original figure for marine fisheries is due to enlargement of tuna fleets and fishing grounds over all the world ocean, the continuous increase of tuna fishing power by in board equipment and remote sensing equipment for searching and scouting (on board, aircraft, satellite, telecommunication_). During the last 20 years, the log-associated tuna fishing has contributed to the local individual and tuna fleets efficiency and fishing power either for large industrial tuna seiners by radio-equipped buoys on natural (debris) or artificial man-made logs. The same trend is noted for numerous artisanal tuna and large pelagic coastal fisheries on moored fishing aggregating devices and networks. The first part of the paper is a review of data and results to assess and rank the "Surfaces prospected by in board tuna seiners and associated aircraft and satellite technics" (visual, radar, sar-radar and satellite altimetry sensors). The final objective is the comparison with the surfaces and volumes associated to fads. Since 20 years, tuna ecology and behaviour data from ultrasonic tagging (short-term depth/distance/time migration around logs and fads) are used for fishing of tuna associated with floating objects, namely fads. The second part of this paper is an "Assessment of fad's aggregating associated surface and volume" linked with oceanographic data: large oceanic geostrophic current and observed drift speed of radio-equipped fads in the Indian Ocean. Using the available data on fads, tuna fishing technology linked with oceanographic and biological data results from ultrasonic tuna tracking experiments, the paper is an attempt to identify and place the fads technology in the scale of tuna fishing devices as a contribution to the increase of tuna fishing power either individual tuna boat or tuna fleets.Original Abstract: La production mondiale des pecheries thonieres est actuellement de l'ordre de 3 millions de tonnes par an et conserve depuis pres de 50 ans un taux de croissance annuel soutenu. Cette croissance, exceptionnelle pour un secteur des peches maritimes, est due a plusieurs causes: accroissement des effectifs et des puissances de peche des grandes flottes thonieres industrielles oceaniques qui exploitent les ressources thonieres de l'ocean mondial et le developpement conjoint de nouvelles techniques de peche et de nouvelles technologies d'aide a la peche, telles que les dispositifs de concentration de poissons (DCP). L'accroissement de la puissance individuelle des navires est du au developpement de la construction navale (mecanisation, propulsion, hydraulique, conservation et traitement a borda) et a l'utilisation d'une gamme diversifiee d'aides a la peche : navigation, telecommunication, localisation des zones favorables, detection visuelle ou radiometrique assistee par equipement a bord, en helicoptere et avion, detection acoustique, detection par radar de bord, radar-avion ou, a terme, antenne SAR sur satellite. Plus recemment, soit depuis 20 ans, les caracteristiques du comportement, migration de court terme, agregation et concentration des poissons pelagiques, fixation et retention des bancs de thons, sont utilisees, par les dispositifs de concentration de poissons (DCP) ancres ou derivants. Cette contribution a pour objectif de situer et placer les DCP fixes ou derivants sur cet ensemble de techniques d'aide a la peche thoniere. Les donnees pour cet essai de classement sont d'ordres biologique, ethologique et comportementaux (amplitude de deplacement des thons et dimension de la sphere d'attraction d'un DCP) et d'ordres environnemental et oceanographique : masse d'eau concernee par un DCP dans une large veine de courant oceanique ou cotier. On tente de quantifier et d'ordonner les surfaces et les volumes prospectes par les thoniers et particulierement les volumes et masses d'eau exploites par les thoniers utilisant des DCP. Ce classement des DCP dans la serie des dispositifs d'aide a la peche thoniere facilitera l'appreciation de leur contribution a l'augmentation des puissances de peche des thoniers.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15297/12656.pdf
http://archimer.ifremer.fr/doc/00042/15297/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
CONTEXT: Chlordecone, an environmentally persistent organochlorine insecticide used intensively in banana culture in the French West Indies until 1993, has permanently polluted soils and contaminated foodstuffs. Consumption of contaminated food is the main source of exposure nowadays. We sought to identify main contributors to blood chlordecone concentration (BCC) and to validate an exposure indicator based on food intakes. MATERIAL AND METHODS: We used a food frequency questionnaire (FFQ) completed by a sample of 194 pregnant women to estimate their dietary exposure to chlordecone and compared it to blood levels. In a first approach, chlordecone daily intake was estimated as the product of daily eaten quantity of 214 foodstuffs, multiplied by their chlordecone content, and summed over all items. We then predicted individual blood chlordecone concentration with empirical weight regression models based on frequency of food consumption, and without contamination data. RESULTS: Among the 191 subjects who had BCC determination, 146 (76%) had detectable values and mean BCC was 0.86 ng/mL (range < LOD-13.2). Mean per capita dietary intake of chlordecone was estimated at 3.3 microg/day (range: 0.1-22.2). Blood chlordecone levels were significantly correlated with food exposure predicted from the empirical weight models (r=0.47, p<0.0001) and, to a lesser extent, with chlordecone intake estimated from food consumption and food contamination data (r=0.20, p=0.007). Main contributors to chlordecone exposure included seafood, root vegetables, and Cucurbitaceous. CONCLUSION: These results show that the Timoun FFQ provides valid estimates of chlordecone exposure. Estimates from empirical weight models correlated better with blood levels of chlordecone than did estimates from the dietary intake assessment.
ISSN: 0013-9351

inserm-00517109
http://www.hal.inserm.fr/inserm-00517109
http://www.hal.inserm.fr/inserm-00517109/document
http://www.hal.inserm.fr/inserm-00517109/file/Pesticide_exposureofpregnantwomeninGuadeloupe.pdf
DOI : 10.1016/j.envres.2009.10.015

Résumé : The management of marine fish stocks has stayed non-spatial, considering spatial distributions and their consequences on demography as implicit. But the impacts of climate change and the anthropisation of habitats now require to consider spatial procedures explicitly. The work presented here starts with the question of evaluating population abundance, which requires the modelling of spatial distributions (section 1). Then an ecological understanding of the multi-scale nature of distributions is investigated (section 2). Last, we study how demographic population dynamics depends on the spatial organisation of life cycles (section 3). In this work, the approach has been to combine data acquisition at sea with statistical characterisation and modelling. The application of geostatistics to fisheries survey data provided a solution to abundance evaluation and mapping for many different survey designs. A variety of models were implemented (stationary, non-stationary, non-linear, multivariate, spatio-temporal), depending on the statistical characteristics of the data and the problem posed. Sampling bias were identified by combining different survey methods. New procedures for assessing stocks based on indicators including spatial ones were developed, which prepared for ecosystem assessments. (...)
La gestion des stocks de poissons marins est longtemps restée a-spatiale, considérant implicites les mécanismes d’organisation spatiale qui soutiennent la distribution géographique des ressources et leur dynamique démographique. Mais l’impact du changement climatique et l’anthropisation des habitats nécessitent d’en tenir compte explicitement. Partant de questions d’évaluation qui ont nécessité la modélisation des distributions spatiales (section 1), le déterminisme écologique de ces distributions a ensuite été abordé à différentes échelles (section 2) puis ont été envisagées les conséquences de l’organisation spatiale sur la dynamique démographique des populations (section 3). L’approche scientifique suivie intègre l’acquisition de données à la mer, la caractérisation statistique et la modélisation. L’application de la géostatistique aux données des campagnes halieutiques permet de proposer une solution à l’estimation d’abondance et la cartographie pour une variété de plans d’échantillonnage. Différents modèles sont mis en oeuvre (stationnaires, non-stationnaires, non-linéaires, multivariés, spatio-temporels) en fonction du comportement des données et du problème posé. Des biais d’échantillonnage sont identifiés en combinant différentes méthodes d’échantillonnage. Des procédures nouvelles d’évaluation de stocks à partir d’indicateurs dont des indicateurs spatiaux sont développées, qui préparent à l’évaluation des écosystèmes. (...)

Droits : Ifremer, UPMC
http://archimer.ifremer.fr/doc/00013/12410/9197.pdf
http://archimer.ifremer.fr/doc/00013/12410/

Éditeur(s) : Elsevier
Résumé : A field survey was conducted on two intensive shrimp farms using similar technical practices: one (DF) historically affected by a vibriosis, the other (HC) in which the pathogen has been observed although no mortality event has occurred. Because historical data suggest that eutrophication process may directly or indirectly play a role in the disease outbreak, we focussed our research on its dynamics. A higher variability of the phytoplanktonic compartment linked to an imbalance in the molar N:P ratio was observed in farm DF compared to farm HC, implying a modification on the linkage between the bacteria and phytoplankton compartments at DF. The beginning of the mortality outbreak at DF followed a shift from picoto nanophytoplankton. The organic matter mineralization process at the water-sediment interface may explain the disturbance observed in the water column during eutrophication. The consequences of this disturbance on shrimps' health status and pathogen ecology are discussed. (C) 2009 Elsevier Ltd. All rights reserved.
Marine Pollution Bulletin (0025-326X) (Elsevier), 2010-03 , Vol. 60 , N. 3 , P. 402-411

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00002/11368/8119.pdf
DOI:10.1016/j.marpolbul.2009.10.012
http://archimer.ifremer.fr/doc/00002/11368/

Résumé : Les études écologiques sont maintenant considérées comme prometteuses en raison de leur capacité à intégrer dans un même modèle autant des facteurs individuels que populationnels. Le mouvement récent de l’open data pourrait jouer un rôle important dans la pérennisation des démarches multidisciplinaires. Cette thèse montre que l’association des méthodes écologiques aux données publiques permet d’éclairer sous un angle nouveau des problématiques des maladies infectieuses.En Guyane Française, des méthodes écologiques dites de séries temporelles couplées aux données climatiques libres ont contribué à une meilleure compréhension du rôle du climat sur la dynamique de la transmission du paludisme, de la leishmaniose cutanée ainsi que de l’histoplasmose disséminée. L’utilisation de méthodes écologiques sur des données libres de la littérature scientifique concernant la séroprévalence toxoplasmose dans les populations humaines a permis d’identifier les principaux facteurs influençant le niveau de séroprévalence globale et indirectement du risque de toxoplasmose congénital associé. L’association de données onusiennes à des méthodes écologiques a permis de montrer qu’une prévalence importante d’ascaridiose est associée à une réduction par 10 de l’incidence du paludisme et l’impact significatif de la corruption sur la mortalité juvéno-infantile et sur les résistances aux anti-tuberculeux. Ces études montrent que l’association des méthodes écologiques aux données publiques permet d’éclairer sous un angle nouveau des problématiques des maladies infectieuses. Ce type d‘étude fournit la flexibilité nécessaire à l’étude des interactions complexes des nombreux déterminants de la santé.
Ecological studies are now considered promising because of their ability to integrate as well as individual factors than populational ones in the same model. The recent open data movement could play an important role in the sustainability of multidisciplinary approaches. The studies developed in this thesis show that the combination of ecological methods with open data could give original results in the issues of infectious diseases.In French Guiana, ecological methods called time series, coupled with open climate data, have contributed to a better understanding of the role of climate on the dynamics of malaria, cutaneous leishmaniasis and disseminated histoplasmosis. The use of ecological methods with open data from the scientific literature concerning toxoplasmosis seroprevalence in human populations has permitted to identify the main factors influencing the level of overall seroprevalence and indirectly to estimate the associated risk of congenital toxoplasmosis.The combination of UN data to ecological methods has shown that a high prevalence of ascariasis is associated with a reduction from 10 in the incidence of malaria and that corruption has a significant impact on child mortality and resistance to TB.The various studies developed in this thesis show that the combination of ecological methods to public data sheds a new light on the issues of infectious diseases. This type of study provides the flexibility to study the complex interactions of many determinants of health.

http://www.theses.fr/2011AGUY0482/document

Éditeur(s) : Gauthier-Villars
Résumé : The variability of ''yellow substance'' in waters of the Skagerrak and the Kattegat was studied during the international Skagex programme in 1990 and 1991. Data on attenuation of light and fluorescence of dissolved organic matter (DOM) in sea water were collected with a spectral transmissiometer and a submersible fluorometer within a depth range of 0-250 m at several stations. More than fifty-fold variations of fluorescence intensity over space and time were due to the combined action of different sources of DOM in the straits. The surface maximum of fluorescing DOM, related to river outflow, was spreading from Oslo fjord to the central Skagerrak in late spring. This maximum may be ecologically important because it diminishes shortwave PAR. In the autumn the brightest DOM fluorescence was found in the Kattegat and along the Norwegian coast in accordance with earlier studies. The local minima of DOM fluorescence are associated with the Jutland current. Both the instability of the current and a ten-fold difference in DOM content between deep layers of the Skagerrak and Kattegat resulted in strong synoptic variability of fluorescence in the transitional area between the straits. Seasonal and synoptic variabilities of ''yellow substance'' were minimal in the southern Kattegat. The vertical gradients of DOM fluorescence were mostly negative at the depth of the thermocline of the open Skagerrak in spring, reaching values of 40-50 % m-1. Fine structure and complex shape were inherent to fluorescence profiles from areas of intensive water mixing. DOM fluorescence closely covaried with attenuation of UV light: the correlation coefficient was + 0.9 for wavelength w <= 350 nm regardless of season. The inverse dependence between wavelength derivative and magnitude of UV attenuation in the straits did not change with season. DOM fluorescence and water salinity were negatively correlated at depths of 25-50 m but they varied independently in the upper 10 m. No significant correlation between fluorescence and nitrates has been found. Estimates of correlation with phosphates ranged from 0.7 to 0.8. In general, the changes of fluorescence were due to variations of DOM content in sea water but not to variability of DOM composition or state. The properties of DOM fluorescence in the Skagerrak-Kattegat area make it a useful natural tracer of water movements suitable for active remote sensing with airborne lidar.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1993 , Vol. 16 , N. 2 , P. 115-125

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00099/21041/18667.pdf
http://archimer.ifremer.fr/doc/00099/21041/

Éditeur(s) : ISTPM
Résumé : This paper is a study of the feeding ecology of Macrouridae. After Data on their taxonomy and on the stomach contents, the author gives the results obtained: coefficient of vacuity, indication of a prey frequency, percentage in number and in weight, the mean number of prey per stomach, the mean weight of the prey, the alimentary coefficient of a prey. The diet of every species of Macrouridae and the characteristics of feeding in these species are described. He concludes with considerations on the Macrouridae in the ocean and their geographical distribution, and on the deep feeding chain, especially the trophic role of different groups of preys. It is thought that, in the Macrouridae, the alimentary diet is little specialized, and based on benthic and pelagic preys and a tendency to microphagy which can be considered an adaptation to a deep life. Feeding helps determine the area that the fish inhabits at great depths, particularly their vertical distribution which seems to be in direct relation with feeding ecology.
Revue des Travaux de l'Institut des Pêches Maritimes (0035-2276) (ISTPM), 1978-09 , Vol. 42 , N. 3 , P. 177-261

Droits : Ifremer
http://archimer.ifremer.fr/doc/1978/publication-1957.pdf
http://archimer.ifremer.fr/doc/00000/1957/