Le suivi socio-économique des usages des récifs coralliens et des pressions anthropiques qu’ils génèrent

in "Faisabilité pour le suivi socio-économique des récifs coralliens à l’aide d’indicateurs", David G., 201

Les petits états et territoires insulaires face aux changements climatiques : vulnérabilité, adaptation et développement

Sur l'île d'Anjouan, aux Comores, les premiers levés topographiques effectués sur les plages entre 2008 et 2009 montrent des morphotypes de profils à tendance convexe ou concave accusée. L'évolution de ces profils de plages est influencée par l'extraction du sable et par l'exposition aux forçages météo-marins. L'extraction du sable de plage est plus importante sur les plages avec des profils concaves accusés que celles avec des profils à tendance convexe. L'érosion qui en résulte est souvent confondue avec les effets du changement climatique annoncé. Dans ce contexte, avec le soutien de la communauté internationale, les pouvoirs publics développent une stratégie de construction de murs pour protéger les populations et les infrastructures installées sur les littoraux impactés. Ce choix risque d'accentuer la fragilisation du littoral et contraste avec la perception réaliste des acteurs de l'extraction du sable de plage. Ces derniers estiment que la lutte contre l'érosion du littoral ne peut se faire que par l'analyse des causes des extractions et la proposition de solutions alternatives, notamment sociales

Coastal and marine biodiversity of La Réunion

98-103Réunion Island marine biota comprise 4374 taxon records. Algae, scleractinians, hydrozoans, molluscs (except nudibranchs and cephalopods) and vertebrates are the better known taxa. Sponges, cnidarians (except hard corals and hydroids), crustaceans and echinoderms are zoological groups that need more investigations. Species diversity of ctenophores, platyhelminthes and others worms, lophophorates and tunicates is completely unknown. In order to increase accessibility to these records, taxa and species distribution data have been recorded in a new online interoperable database, developed by software engineers of Réunion University, and integrated in the information system of the coastal zone network project (Système d’information du Littoral, SIL). Rocky coasts constitute the largest coastal marine habitat of Réunion Island, but coral reefs have been more investigated. Among them, the Saint-Gilles/La Saline coral reef complex is the most studied area and the other reefs and platforms have been neglected so far. Further, hardly any studies exist for the rocky coast and the deep-water ecosystems. Although Réunion coral reefs shelter 191 species registered either in IUCN red list (2003), CITES, CMS and regional Nairobi conventions, the marine biodiversity and the coastal habitats are under increasing anthropogenic threats. In spite of the high species richness, the high number of threatened species and the numerous economic activities that depend of the health of coral reefs, no marine protected areas exist as yet in Réunion, mainly because of disagreements between stakeholders

Spatial analysis of malaria distribution in the Union of Comoros

International audienceBackground: Malaria remains endemic in Comoros. In 2006, malaria was the leading cause of mortality, morbidity and consultation in hospitals. The Government of the Union of the Comoros is committed in the fight against malaria through the establishment of a National Strategic Plan in 2007 that was later updated for the period 2012-2016. The results of these efforts show that the disease is in a pre-elimination phase. Despite a clear decline of malaria several aspects of its epidemiology should be clarified including the identification of endemic areas.Methods: Monthly cases, as reported by the “Programme National de lutte Contre le paludisme” (PNLP) from 2010 to 2014, were geo-referenced in each island at the sanitary district level. The incidence of malaria by district was calculated using population data from the National Census. We completed the spatial database with data on environmental and social factors including meteorology, physical geography, land use (analyzed by remote sensing of SPOT 5 satellite images), population characteristics, and health care facilities. We performed statistical analyzes to show the relationships between the variables and the prevalence of malaria.Results: The mapping of malaria incidence between 2010 and 2014 shows its heterogeneity among the 17 sanitary districts. Five districts (Hambou, Centre, Fomboni, Mutsamudu and Pomoni) reveal a high endemicity. Also we have highlighted the spatial relationships between malaria incidences and environmental and socio-demographic variables.Conclusion: This work is the first spatial analysis of the epidemiology of malaria in Comoros. It contributes to a better understanding of the spatial dynamics of malaria to help the Ministry of Health to eradicate malaria by 2016

Validation of a fish larvae dispersal model with otolith data in the Western Indian Ocean and implications for marine spatial planning in data-poor regions

The pelagic larval period is probably the least understood life stage of reef fish, yet the processes of larval dispersal and settlement exert a strong influence on the persistence of reef fish populations. A thorough understanding of these processes is essential to determining whether distant populations are connected and how to adapt management plans to patterns in connectivity. Managers may erroneously assume that local populations are isolated when they are actually replenished by distant reefs beyond their jurisdiction. Researchers increasingly rely on numerical hydrodynamic models that simulate the spatio-temporal dispersal of larvae by ocean currents to elucidate these connections and guide marine spatial planners, yet relatively little work has been done to validate these models with empirical data. In this study, we tested a dispersal simulation model against in situ observations of young post-larval fish to investigate a whether larvae settling at La Reunion (in the western Indian Ocean) might have originated at Mauritius, 200 km distant. First, we collected post larval specimens of honeycomb grouper (Epinephelus merra) shortly after an episodic mass settlement that occurred in 2002 at La Reunion. Using sclerochronology, we established the age of the fish from their otoliths. Finally, we simulated dispersal of larvae from La Reunion, Mauritius, and other reefs in the region by ocean currents using a 20 Eulerian advection-diffusion model driven by current velocities derived from satellite remote sensing. The simulation suggested that larvae spawned at la Reunion were carried away from the island while larvae spawned at Mauritius were carried to La Reunion. The otolith-derived ages of the fish were compatible with this hypothesis, when we accounted for the time required for larvae to drift from Mauritius to La Reunion. The combined results suggest a dispersal connection from Mauritius to la Reunion. To best maintain populations of adult reef fish at La Reunion, managers should protect stocks spawning at Mauritius. Although more study is needed to characterize patterns of regional connectivity and account for seasonal and inter-annual variations in these patterns, the example presented here demonstrates the possibility of distant connections in the western Indian Ocean. We urge managers in the region to look beyond their own jurisdictions, view their jurisdictions as part of a connected network, and undertake a collaborative approach to protecting the network as a whole