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International audience; Inter- and intraspecific competition can lead to resource partitioning in sympatric species, processes likely affected by environmental productivity and population size. We investigated the foraging behaviour and diet of masked (Sula dactylatra) and red-footed (S. sula) boobies at Tromelin Island, western Indian Ocean, to examine the role of resource partitioning in the foraging strategies of these sympatric species in an extreme oligotrophic environment. We compared our results to published studies with differing environmental conditions or population sizes. We used GPS loggers and Argos transmitters to track foraging movements and used time-depth recorders to estimate dive depths. Masked boobies travelled further and at faster rates than red-footed boobies, and sexes did not differ in foraging behaviour. Based on randomization tests, the foraging range of each species (95% utilization distribution; UD) overlapped significantly. However, at core foraging areas (50% and 25% UD), interspecific segregation was greater than expected by chance alone. No intraspecific spatial segregation was detected between sexes. Environmental characteristics of area-restricted search zones differed between species, but not sexes; masked boobies utilized warmer, deeper, and less windy oceanic environments than red-footed boobies. Masked boobies attained greater diving depths than red-footed boobies and consumed primarily flying fish, whereas red-footed boobies consumed mostly squid. Red-footed and masked boobies breeding in the extreme oligotrophic environment near Tromelin demonstrated greater dietary partitioning differences in foraging ranges compared to a less oligotrophic environment. This suggests that environmental productivity may play a role in processes of resource partitioning in these sympatric species.

International audience; We isolated and characterized 16 polymorphic microsatellite loci for Lytocarpia brevirostris (Aglaophe- niidae), a hydrozoan common in the tropical Indo-Pacific region. Four to 34 alleles per locus were detected at the Indo-Pacific scale. At the population level, observed (Ho) and expected (He) heterozygosities ranged across 0.100–0.625 and 0.097–0.597, respectively. Three markers showed significant deviation from Hardy–Weinberg equi- librium, all of them presenting null alleles. Linkage dis- equilibrium was detected in three pairs of loci among 120. These primers provide powerful tools for studying popu- lation genetic diversity and the implication of life cycle strategies on population differentiation in tropical hydro- zoans. This will be valuable for the conservation of coral reefs biodiversity and the design of marine protected areas.

International audience; The reflection of baseline isotopic signals along marine food chains up to higher trophic levels has been widely used in the study of oceanic top predators but rarely for intertidal predators. We investigated variation in the δ13C and δ15N ratios of a sedentary, rocky shore predator, the African black oystercatcher Haematopus moquini, over ~2000 km of the southern African coastline, which is characterized by strong biogeographic patterns in primary productivity and intertidal communities. Blood and feathers from breeding adults and chicks and muscle tissues from primary prey items (mussels and limpets) were sampled between southern Namibia and the southeast coast of South Africa. 15N enrichment was observed between the southeast and west coasts in oystercatcher tissues and their prey, mirroring an isotope shift between the oligotrophic Agulhas Current on the east coast and the eutrophic Benguela upwelling system on the west coast. Oystercatcher blood showed δ13C values that varied between those of the carbon-depleted mussels and the carbon-enriched limpets along the coastline, which reflected changes in the proportion of grazers and filter feeders in the oystercatcher diet across the sampling range. The geographic shift in diet, dominated by mussels on the west coast and composed of mixed proportions of mussels and limpets on the southeast coasts, strongly reflected regionally high abundances of the invasive Mediterranean mussel Mytilus galloprovincialis. Finally, isotope signatures of blood and feathers displayed a strong correlation throughout the study area, indicating seasonal stability in environmental conditions and feeding habits of the adults. There were, however, local discrepancies on the south coast that indicated movement of adults occurred outside the breeding season possibly in response to a lower abundance of food in this region. Overall, the results indicate that the influence of regional oceanic conditions on the base of the food web can penetrate to the predator level, but that local effects can be incorporated within this pattern.

Theories of species coexistence have played a central role in ecology and evolutionary studies of the origin and maintenance of biodiversity in highly diverse communities. The concept of niche and associated theories predict that competition for available ecological space leads to a ceiling in species richness that influences further diversification patterns. By contrast, the neutral theory supports that speciation is stochastic and diversity independent. We examined the phylogenetic community structure and diversification rates in three families and 14 sites within coral reef fish communities from the Indian and Pacific oceans. Using the phylogenetic relationships among 157 species estimated with 2300 bp of mitochondrial DNA, we tested predictions in terms of species coexistence from the neutral and niche theories. At the regional scale, our findings suggest that phylogenetic community structure shifts during community assembly to a pattern of dispersion as a consequence of allopatric speciation in recent times but overall, variations in diversification rates did not relate with sea level changes. At the local scale, the phylogenetic community structure is consistent with a neutral model of community assembly since no departure from a random sorting of species was observed. The present results support a neutral model of community assembly as a consequence of the stochastic and unpredictable nature of coral reefs favoring generalist and sedentary species competing for living space rather than trophic resources. As a consequence, the observed decrease in diversification rates may be seen as the result of a limited supply of living space as expected in a finite island model.

Spatial and seasonal variability of sources of particulate organic matter (POM) were evaluated in a coral reef ecosystem. Reef water POM was sampled monthly along a south-north gradient. The passage of tropical cyclone Gamede, which crossed Reunion Island in February 2007, provided an ideal opportunity to examine the impact of high river discharge. Stable isotope composition (δ13C, δ15N) was determined in oceanic, riverine and reef water POM, sedimentary organic matter (SOM), benthic primary producers and detritus. Trace elements (Ti, Fe, Cr, Ni, Cu, Zn) measured in SOM were used as additional terrestrial tracers. Stable isotope analysis of reef water showed that POM was affected by anthropogenic non-point nutrient sources, water circulation patterns and residence time. During the cold and dry season, the southern end of the reef received organic matter input derived from ocean primary production, while the middle and northern reef water POM originated primarily from SOM, reflecting an important bentho-pelagic coupling process. During the hot and wet season, reef water was enriched in benthic detritus due to higher autochthonous production. We found important spatial variability in POM sources, highlighting the importance of small-scale (hundreds of meters) studies when investigating ecosystem functioning. Although coastal tidal currents transported some river discharge material to the south of the reef, riverine POM input was limited, even after cyclone passage. We hypothesized that the major effect of the cyclone was the export of SOM and benthic detritus out of the system and that persistent disturbances such as groundwater discharges can be of greater importance than a cyclone in long-term degradation of ecosystems.

International audience; Gadfly petrels are strictly oceanic seabirds that range very far from their breeding grounds. Foraging movements outside the breeding season are poorly described. We used global location sensing (GLS) to describe the migration pathways and wintering habitats of Barau's petrels Pterodroma baraui, an endemic, endangered seabird of Reunion Island (western Indian Ocean). In 2 consecutive years, petrels migrated far eastward, up to 5000 km from their breeding colony, to the central and eastern Indian Ocean. Migration pathways, timing, and wintering areas varied little among individuals, and non-breeding areas were remarkably consistent between years. There was no sexual variation in migration patterns. Barau's petrels did not occur in the most productive areas of the Indian Ocean (Arabian Gulf and Somalia upwelling region) but instead foraged over warm oligotrophic and mesotrophic waters. Tracked birds consistently occurred in areas with relatively strong and consistent easterly winds, and avoided northern regions with weaker westerly winds. Our results indicate that Barau's petrels use an expansive wintering area between the western South Equatorial Current and the eastern Equatorial Counter Current, characterised by warm sea surface temperatures (SST) and low productivity. However, wind regimes in the Indian Ocean are strongly influenced by the Asian Monsoon; in this particular area, wind and currents may create a frontal system where prey are aggregated, increasing their accessibility for Barau's petrels. These results provide important baseline information for conservation, and are useful for the selection of potential marine reserves and the evaluation of effects of pollution or climate change on this highly threatened species.

Most animals, including birds, have cyclic life histories and numerous studies generally conducted on captive animals have shown that photoperiod is the main factor influencing this periodicity. Moon cycles can also affect periodic behavior of birds. Few studies have investigated the influence of these environmental cues in natural settings, and particularly in tropical areas where the change in photoperiod is slight and some bird species keep cyclic behaviors. Using miniaturized light sensors, we simultaneously investigated under natural conditions the influence of photoperiod and moon phases on the migration dates and at-sea activity of a tropical seabird species, the Barau's petrel, throughout its annual cycle. Firstly, we found that birds consistently started their pre- and post-breeding migrations at precise dates corresponding in both cases to a day-duration of 12.5 hours, suggesting a strong influence of the photoperiod in the regulation of migration behavior. We also found that mean population arrival dates to the colony changed from year to year and they were influenced by moon phases. Returns at their colonies occurred around the last full moon of the austral winter, suggesting that moon cycle is used by birds to synchronize their arrival. Secondly, variations of day-time activity were sinusoidal and correlated to seasonal changes of daylength. We thus hypothesize that the photoperiod could directly affect the behavior of the birds at sea. Night-time at-sea activity exhibited a clear cycle of 29.2 days, suggesting that nocturnal foraging was highly regulated by moon phase, particularly during the non-breeding season. To our knowledge, this is the first study to document a mixed regulation of the behavior of a wild bird by photoperiod and moon phases throughout its annual cycle.

International audience; Poster about diversification of terrestrial and marine biotas in the Southwest Indian Ocean (Program ANR BIOTAS)

This review presents environmental and biological indicators of the impact of three major categories of inputs in coral reef lagoons i.e. particles, nutrients and metals. Information was synthesized to extract well established indicators together with some interesting new concepts currently under development, and to provide the reader with an assessment of their respective advantages and drawbacks. The paper has been organized according to the capacity of three categories of indicators to respond either in a specific or a non specific way to a given source of input. The first section focuses on abiotic indicators which main interest is to respond instantaneously and in a truly specific way to a given source of input. The second and third sections present informations on bioindicators either at the sub-individual level or at the individual to community level, indicator specificity generally decreasing as a direct function of biological or ecological complexity. This review showed that even though significant work has already been done on coral reef ecosystems, much more scientific studies are still needed to answer the growing local demands for simple and truly validated tools to be used in environmental surveys. It is further stressed that, due to the biological and environmental diversity of coral reef lagoons, a preliminary step of on-site validation must be considered as an absolute prerequisite when indicators are planned to be used in the frame of a local environmental monitoring programme.; Cette synthèse bibliographique présente les caractéristiques environnementales et biologiques pouvant être utilisées comme indicateurs des effets de trois grandes catégories d'apports exogènes dans les milieux récifo-lagonaires : les particules, les éléments nutritifs et les métaux. Les données de la littérature ont été analysées pour en extraire des indicateurs reconnus ainsi que de nouveaux concepts en cours de développement, et afin d'examiner leurs avantages et inconvénients respectifs. L'article a été structuré selon la capacité de trois types d'indicateurs à répondre de manière spécifique ou non spécifique à l'une des trois catégories d'apports cités précédemment. En premier lieu, les indicateurs abiotiques qui ont pour principal intérêt de répondre instantanément et spécifiquement à l'un des trois types d'apports, puis les bio-indicateurs respectivement considérés à l'échelle infra-organisme ou à une échelle allant de l'organisme à la communauté. La spécificité de ces indicateurs diminuant en fonction de l'augmentation de la complexité biologique et écologique. Bien qu'il existe déjà un nombre important de travaux portant sur les systèmes récifo-lagonaires, un effort scientifique majeur reste nécessaire pour répondre à des demandes croissantes de définition d'outils simples et validés pouvant être utilisés dans le cadre de la surveillance de l'environnement. De plus, et compte tenu de la diversité biologique et environnementale des lagons et des récifs coralliens cette étude montre que l'utilisation d'indicateurs, dans le cadre de programmes de suivi environnementaux à l'échelle locale, passe par une phase préliminaire indispensable de validation sur site, des indicateurs sélectionnés.

International audience; This study presents an inventory of possible chemical reactions affecting, or having affected, the Venus surface. Fluid rock reactions are simulated using experiments under conditions close to the present surface. Slabs or powder of several natural and synthetic silicate material (crystalline fresh basalt, altered basalt, obsidian, pumice and basalt glass) were reacted at 475°C in CO 2-H 2 O-H 2 S-SO 2-CO gas mixture. Most of the runs were carried out at roughly 90 bars with a duration of one week, some experiments having longer (one month) or shorter (one day) durations. The role of H 2 O content was explored through a wide range of water pressure: from dry gas for the current Venus conditions up to 590 bars (86%H 2 O) for early Venus (or other early terrestrial planets). The gas phase was sampled before the completion of the runs for chemical analysis of major gas components (CO, H 2 S, SO 2) as well as trace elements possibly released by the rocks. The altered samples were examined by a suite of mineralogical and chemical techniques (scanning and transmission electron microscopy, X-ray diffraction and spectroscopy). In dry atmosphere, the redox potential of the gas was close to the Ni/NiO buffer (−21.3 to −27.3 log fO 2), thus close to the current Venus conditions. The sample alteration is tenuous and limited to surface oxidation of glasses and coating of olivine by iron oxides, as well as the general deposition of (Ca,Na)SO 4 at the sample surface. The oxidation of glass is reflected in the formation of magnesioferrite under the surface and is accompanied by the release of Ca, Mg and Na into the gas phase or mineralized as sulfate at the surface. In wet atmosphere, obsidian recrystallizes into a mixture of plagioclase and amphibole while basaltic glass produced non-expandable clays minerals: chlorite-type (2:1:1) at the surface and likely celadonite (2:1) below the surface. Olivine is preserved. Using obsidian (the most alterable material) as a proxy of aluminosilicates, we discuss the surface reactions operating under supercritical conditions, and we used a shrinking-core equation for modeling the long-term reactions. These parametric exploration offer new insights into processes having affected the surface of Venus and contribute to the discussion of open questions such as the fate of water or the lifetime of vitreous dust or fine grain material if present in the current or past Venusian environment. Longer duration experiments will provide more kinetic parameters that can be extrapolated to the geologic history of Venus.

International audience; Population genetics has been increasingly applied to study large sharks over the last decade. Whilst large shark species are often difficult to study with direct methods, improved knowledge is needed for both population management and conservation, especially for species vulnerable to anthropogenic and climatic impacts. The tiger shark, Galeocerdo cuvier, is an apex predator known to play important direct and indirect roles in tropical and subtropical marine ecosystems. While the global and Indo‐West Pacific population genetic structure of this species has recently been investigated, questions remain over population structure and demographic history within the western Indian (WIO) and within the western Pacific Oceans (WPO). To address the knowledge gap in tiger shark regional population structures, the genetic diversity of 286 individuals sampled in seven localities was investigated using 27 microsatellite loci and three mitochondrial genes (CR, COI, and cytb). A weak genetic differentiation was observed between the WIO and the WPO, suggesting high genetic connectivity. This result agrees with previous studies and highlights the importance of the pelagic behavior of this species to ensure gene flow. Using approximate Bayesian computation to couple information from both nuclear and mitochondrial markers, evidence of a recent bottleneck in the Holocene (2,000–3,000 years ago) was found, which is the most probable cause for the low genetic diversity observed. A contemporary effective population size as low as 111 [43,369] was estimated during the bottleneck. Together, these results indicate low genetic diversity that may reflect a vulnerable population sensitive to regional pressures. Conservation measures are thus needed to protect a species that is classified as Near Threatened.

International audience; The reduced species richness typical of oceanic islands provides an interesting environmental setup to examine in natura the epidemiological dynamics of infectious agents with potential implications for public health and/or conservation. On Amsterdam Island (Indian Ocean), recurrent die-offs of Indian yellow-nosed albatross (Thalassarche carteri) nestlings have been attributed to avian cholera, caused by the bacterium Pasteurella multocida. In order to help implementing efficient measures for the control of this disease, it is critical to better understand the local epidemiology of P. multocida and to examine its inter- and intra-annual infection dynamics. We evaluated the infection status of 264 yellow-nosed albatrosses over four successive breeding seasons using a real-time PCR targeting P. multocida DNA from cloacal swabs. Infection prevalence patterns revealed an intense circulation of P. multocida throughout the survey, with a steady but variable increase in infection prevalence within each breeding season. These epizootics were associated with massive nestling dies-offs, inducing very low fledging successes (≤ 20%). These results suggest important variations in the transmission dynamics of this pathogen. These findings and the developed PCR protocol have direct applications to guide future research and refine conservation plans aiming at controlling the disease.

Este artículo contiene 10 páginas, 5 figuras., Without drastic efforts to reduce carbon emissions and mitigate globalized stressors, tropical coral reefs are in jeopardy. Strategic conservation and management requires identification of the environmental and socioeconomic factors driving the persistence of scleractinian coral assemblages—the foundation species of coral reef ecosystems. Here, we compiled coral abundance data from 2,584 Indo-Pacific reefs to evaluate the influence of 21 climate, social and environmental drivers on the ecology of reef coral assemblages. Higher abundances of framework-building corals were typically associated with: weaker thermal disturbances and longer intervals for potential recovery; slower human population growth; reduced access by human settlements and markets; and less nearby agriculture. We therefore propose a framework of three management strategies (protect, recover or transform) by considering: (1) if reefs were above or below a proposed threshold of >10% cover of the coral taxa important for structural complexity and carbonate production; and (2) reef exposure to severe thermal stress during the 2014–2017 global coral bleaching event. Our findings can guide urgent management efforts for coral reefs, by identifying key threats across multiple scales and strategic policy priorities that might sustain a network of functioning reefs in the Indo-Pacific to avoid ecosystem collapse.

Biodiversity hotspots have provided useful geographic proxies for conservation efforts. Delineated from a few groups of animals and plants, biodiversity hotspots do not reflect the conservation status of freshwater fishes. With hundreds of new species described on a yearly basis, fishes constitute the most poorly known group of vertebrates. This situation urges for an acceleration of the fish species inventory through fast and reliable molecular tools such as DNA barcoding. The present study focuses on the freshwater fishes diversity in the Sundaland biodiversity hotspot in Southeast Asia. Recent studies evidenced large taxonomic gaps as well as unexpectedly high levels of cryptic diversity, particularly so in the islands of Java and Bali. The Cypriniformes genera Rasbora and Nemacheilus account for most of the endemic species in Java and Bali, however their taxonomy is plagued by confusion about species identity and distribution. This study examines the taxonomic status of the Rasbora and Nemacheilus species in Java, Bali and Lombok islands through DNA barcodes, with the objective to resolve taxonomic confusion and identify trends in genetic diversity that can be further used for conservation matters. Several species delimitation methods based on DNA sequences were used and confirmed the status of most species, however several cases of taxonomic confusion and two new taxa are detected. Mitochondrial sequences argue that most species range distributions currently reported in the literature are inflated due to erroneous population assignments to the species level, and further highlight the sensitive conservation status of most Rasbora and Nemacheilus species on the islands of Java, Bali and Lombok.

International audience; Metallic and organic pollutants constitute a serious threat for coral reef ecosystems, potentially affecting a great number of species interacting within complex trophodynamic processes. Pesticides, PCBs and trace elements were measured on coral reef communities of three Pacific islands (Moorea, Wallis and New Caledonia) in relation with d15N values, a proxy of trophic level. Several potential sources of organic matter, benthic invertebrates and fish belonging to various trophic strategies were sampled at each island. Wallis and New Caledonia displayed, respectively, the highest concentrations of pesticides and trace elements. In the three islands, most trace element concentrations (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and V) decreased when d15N was rising (i.e. bioreduction), whereas Hg and Se biomagnified with increasing d15N values. Only few trace elements in some islands did not show any significant trend in relation with d15N (i.e., Ag in New Caledonia, Zn in Wallis and As plus Zn in Moorea). PCBs concentrations showed a significant bioreduction in New Caledonia and in Moorea, but a significant biomagnification in Wallis. Aldrin and heptachlor were the only pesticides to show a similar significant bioreduction in the three islands. Other pesticides, such as chlordecone, diazinon, endosulfan I and II, heptachlor-epoxide A and B, lindane and pp’-DDE displayed contrasted patterns (e.g. chlordecone significantly biomagnified in New Caledonia, significantly bioreduced in Wallis and did not displayed any significant trend in Moorea). Finally, for unclear reasons, Moorea displayed only negative significant correlations between d15N and all pesticides (except pp’-DDT). Our results highlight that trophic level, here assessed through d15N values, is a good predictor of metallic trace elements biomagnification or bioreduction in coral reef organisms. However, at large spatial scale, trophic level relevance to predict pesticides and PCBs biomagnification or bioreduction should be considered with caution and studied in close relation with local characteristics.

International audience; The multidisciplinary programme BioReCIE (Biodiversity, Resources and Conservation of coral reefs at Eparses Is.) inventoried multiple marine animal groups in order to provide information on the coral reef health of the Iles Eparses. All five classes of echinoderms were observed by visual census, photographed and later identified. About 100 species are reported, including a few unidentified ones which require further studies. The Holothuroidea and Ophiuroidea are the most diverse. One new species, the asterinid Aquilonastra chantalae O'Loughlin and McKenzie (2013), was discovered in addition to several new records of echinoderms. The illegal fishery targeting holothurians, which are presently highly valuable resources in this zone, is discussed.

Aim Enhanced management of areas important for marine biodiversity are now obligations under a range of international treaties. Tracking data provide unparalleled information on the distribution of marine taxa, but there are no agreed guidelines that ensure these data are used consistently to identify biodiversity hotspots and inform marine management decisions. Here, we develop methods to standardize the analysis of tracking data to identify sites of conservation importance at global and regional scales. Location We applied these methods to the largest available compilation of seabird tracking data, covering 60 species, collected from 55 deployment locations ranging from the poles to the tropics. Methods Key developments include a test for pseudo-replication to assess the independence of two groups of tracking data, an objective approach to define species-specific smoothing parameters (h values) for kernel density estimation based on area-restricted search behaviour, and an analysis to determine whether sites identified from tracked individuals are also representative for the wider population. Results This analysis delineated priority sites for marine conservation for 52 of the 60 species assessed. We compiled 252 data groupings and defined 1052 polygons, between them meeting Important Bird and Biodiversity Area criteria over 1500 times. Other results showed 13% of data groups were inadequate for site definition and 10% showed some level of pseudo-replication. Between 25 and 50 trips were needed within a data group for data to be considered at least partially representative of the respective population. Main conclusions Our approach provides a consistent framework for using animal tracking data to delineate areas of global conservation importance, allowing greater integration into marine spatial planning and policy. The approaches we describe are exemplified for pelagic seabirds, but are applicable to a range of taxonomic groups. Covering 4.3% of the oceans, the sites identified would benefit from enhanced protection to better safeguard the threatened species populations they contain.

International audience; Good governance is paramount to the sustainability of fisheries, and inclusiveness of stakeholder groups has become the centerpiece in the ethos of managing small-scale fisheries. Understanding the effect of governance network structures on fishery sustainability can help guide governance to achieve desired outcomes. Data on resource users, fishing methods, governance networks and classifications of stock health were compiled for 17 sea cucumber fisheries in the Indian Ocean. The subjective influence of the actors and the complexity of governance networks on the health of wild stocks were analyzed. The fisheries differed widely in their resource users, fishing methods and governance networks. Little correspondence was found between the number of nodes in the governance networks and the health (exploitation status) of wild stocks. Government entities dominated the networks but neither their relative influence in the networks nor their proportionate contribution to the number of entities in the networks greatly affected stock health. These findings do not refute the benefits of inclusive governance, but rather suggest that multiple other factors (e.g. inadequate regulations, weak enforcement, high number of fishers) are also likely to play a role in influencing sea cucumber fishery sustainability. These factors must be tackled in tandem with good governance.

As part of the Bagnold Dune campaign conducted by Mars Science Laboratory rover Curiosity, visible/near-infrared reflectance spectra of dune sands were acquired using Mast Camera (Mastcam) multispectral imaging (445–1013 nm) and Chemistry and Camera (ChemCam) passive point spectroscopy (400–840 nm). By comparing spectra from pristine and rover-disturbed ripple crests and troughs within the dune field, and through analysis of sieved grain size fractions, constraints on mineral segregation from grain sorting could be determined. In general, the dune areas exhibited low relative reflectance, a weak ~530nm absorption band, an absorption band near 620 nm, and a spectral downturn after ~685nm consistent with olivine-bearing sands. The finest grain size fractions occurred within ripple troughs and in the subsurface and typically exhibited the strongest ~530nmbands, highest relative reflectances, and weakest red/near-infrared ratios, consistent with a combination of crystalline and amorphous ferric materials. Coarser-grained samples were the darkest and bluest and exhibited weaker ~530nm bands, lower relative reflectances,andstrongerdownturns in the near-infrared, consistent with greater proportions ofmafic minerals such as olivine and pyroxene. These grains were typically segregated along ripple crests and among the upper surfaces of grain flows in disturbed sands. Sieved dune sands exhibited progressive decreases in reflectance with increasing grain size, as observed in laboratory spectra of olivine size separates. The continuum of spectral features observed between the coarse- and fine-grained dune sands suggests that mafic grains, ferric materials, and air fall dust mix in variable proportions depending on aeolian activity and grain sorting. This work was funded by the NASA Mars Science Laboratory Participating Scientist program through the Jet Propulsion Laboratory (contracts 1350588, 1449892, and 1546033). A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The U.S. portion of ChemCam and MSL rover operations was funded by NASA’s Mars Exploration Program. The French contribution to MSL is supported by the Centre National d’Etudes Spatiales (CNES)… E.A.C. thanks NSERC, CSA, CFI, and MRIF for supporting the UW Planetary Spectrophotometer Facility at UW. https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016JE005187

Background Metastatic colorectal cancer (mCRC) is one of the major causes of cancer-related death. Despite the substantial progress in mCRC management, it remains important to identify new therapeutic options and biological markers for personalized medicine. Here, we investigated the expression of claudin-1 (CLDN1), a major tight junction transmembrane protein, in the different colorectal cancer (CRC) molecular subtypes and then assessed the anti-tumor effect of a new anti-CLDN1 monoclonal antibody (mAb). Methods Gene expression profiling and immunochemistry analysis of normal and tumor tissue samples from patients with stage IV CRC were used to determine CLDN1 gene expression. Then, the 6F6 mAb against CLDN1 extracellular part was generated. Its effect on CRC cell cycle, proliferation, survival and migration was assessed in vitro, using a 3D cell culture system, flow cytometry, clonogenic and migration assays. In vivo, 6 F6 mAb efficacy was evaluated in nude mice after subcutaneous xenografts or intrasplenic injection of CRC cells. Results Compared with normal mucosa where it was almost exclusively cytoplasmic, in CRC samples CLDN1 was overexpressed (p

The sea cucumber fisheries have expanded during the past two decades, at a faster rate than the management capacity. The exploitation is now qualified as ‘serial’ and ‘contagious’. I present the most recent trends from the last six years of the FAO capture data. Hong Kong remains the most important market for the imports and re-exports of the processed products, mainly the dry “trepang” (or bêche-de-mer), but also other product forms, which raised difficulties for the analysis. The catches still increase. with new countries developing export fisheries, species targeted change and new products are traded. Rev. Biol. Trop. 65(Suppl. 1): S1-S10. Epub 2017 November 01.

International audience; We found a diversity of Rickettsia spp. in seabird ticks from 6 tropical islands. The bacteria showed strong host specificity and sequence similarity with strains in other regions. Seabird ticks may be key reservoirs for pathogenic Rickettsia spp., and bird hosts may have a role in dispersing ticks and tick-associated infectious agents over large distances.

International audience; Temporal trends in growth of the rusty parrotfish Scarus ferrugineus were studied on a southern Red Sea fringing reef that experiences seasonal changes in environmental conditions and benthic algal resources. Length increment data from tagging and recapture were compared among periods and sexes and modelled using GROTAG, a von Bertalanffy growth model. The growth pattern of S. ferrugineus was highly seasonal with a maximum occurring between April and June and a minimum between December and March. Body condition followed the seasonal variation in growth, increasing from April to June and decreasing from December to March. The season of maximum growth coincided with high irradiation, temperature increases and peak abundance of the primary food source, the epilithic algal community. There was a decline in growth rate during summer (July to October) associated with a combination of extreme temperatures and lowered food availability. There were strong sexual size dimorphism (SSD) and life-history traits. Terminal-phase (TP) males achieved larger asymptotic lengths than initial-phase individuals (IP) (L∞ 34·55 v. 25·12 cm) with growth coefficients (K) of 0·26 and 0·38. The TPs were growing four times as fast as IPs of similar size. Three individuals changed from IP to TP while at liberty and grew eight times faster than IPs of similar size, suggesting that sex change in S. ferrugineus is accompanied by a surge in growth rate. The SSD in S. ferrugineus thus coincided with fast growth that started during sex change and continued into the TP. Faster growth during sex change suggests that the cost associated with sex change is limited.

On coral reefs, feeding by parrotfishes may prevent coral to macroalgal phase shifts by keeping algae in a cropped state. To predict the response of grazers to changing conditions, knowledge of the factors that affect feeding intensity is needed. Therefore, we studied food intake of the parrotfish Scarus ferrugineus on an inshore fringing reef in the southern Red Sea, Eritrea, where seasonality and extreme summer temperatures were expected to influence feeding rates. Bite rates (bites min(-1)), defecation rates (defecations min(-1)) and yield per bite (mass ingested bite(-1)) were estimated for 3 life-phase categories: 20 to 25 cm initial phase (IP), 30 to 35 cm terminal phase (TP) and 30 to 35 cm territorial terminal phase (TTP). The bite rates increased from low levels in the morning to peak values in the afternoon. IP bite rates increased linearly with seawater temperature. For TP, the temperature-bite rate relationship was quadratic, with maximum bite rates at similar to 32 degrees C and lower rates at higher temperatures. Yield per bite in both IP and TP did not differ with time of year. Throughout the year, the total daily bites were highest in IP and lowest in TTP, resulting in similar to 23% lower daily intake in TTP compared to similar-sized TP males. Daily intake of ash-free dry mass of epilithic algal matrix (g AFDM d(-1)) was 7.5 to 9.6 for IP, 12.4 to 17.5 for TP and 8.7 to 13.2 for TTP. Intake and defecation rates and hence gut turnover rates peaked from April to July. The quadratic temperature response of TP suggests that large individuals may be close to their upper thermal limit, implying that temperature rises are likely to negatively affect grazing by large-bodied parrotfishes.

International audience; Coral reefs are characterized by intense herbivory. Spatial patterns in herbivory--particularly along the depth gradient--influence the distribution and abundance of algae. Depth gradients in herbivorous reef fishes are generally assumed to be temporally stable, but this assumption has rarely been questioned. Here, we use underwater visual census and herbivore exclusion experiments to study the community composition and temporal patterns in habitat use by roving herbivorous fishes in an environment characterized by profound seasonal changes in algal biomass and distribution and extreme summer temperatures. Among the 18 species of roving herbivores recorded, parrotfishes were dominant in species richness and biomass, while regional endemic species represented 77 % of the total biomass. During most of the year, roving herbivores aggregate in the shallow reef zones and their biomass declines with depth. The herbivore community on the reef flat is distinct from that in deeper zones. The former is characterized by Siganus rivulatus, Acanthurus gahhm and Hipposcarus harid, while the deeper reef zones are characterized by S. ferrugineus, Chlorurus sordidus and Ctenochaetus striatus. In summer, the distinct community structures among reef zones are lost as reef flat herbivores tend to exploit deeper reef zones and some reef crest species venture on to the reef flat. This summer change in herbivore distribution is also reflected in reduced turf biomass and increased yield to herbivores in the deeper reef zones. Habitat use is related to the feeding mode such that browsers dominate the reef flat and scrapers the reef crest, while the seasonal changes correspond to changes in availability of targeted algal resources. These seasonal changes appear to be driven by the extreme temperatures in summer, reaching 36 °C on the shallow reef flat.

International audience; This study assesses changes in subtidal benthic communities on the largest reef flat in Reunion, Saint-Gilles La Saline, using several types of surveys. Temporal and spatial trends are documented over a 22 year period (1987-2009), thus spanning the 1998 and 2000s bleaching events. The most plausible explanations for the observed trends are proposed. We chose two sites that are characterized by two types of community and metabolism: (1) an oligotrophic site dominated by Acropora corals (Site-Toboggan), where sea-urchins are numerous and macroalgae rare and (2) a dystrophic site dominated by non-Acropora corals, mostly massive and submassive, where macroalgae abound and sea-urchins are almost absent (Site-Planch'Alizés). Results are presented in three parts : Part 1 : general trends of the communities, part 2 : primary producers, part 3 : living corals. Part 1 presents three surveys. Survey 1 reports status and trends across the reef flats in 1993, 1996, and 2002, with all attached benthic components reported at the level of the species where possible. Survey 2 reports composition and changes in associated sedentary organisms such as sea urchins, holothurids, and the Pomacentridae fish Stegastes. Survey 3 focuses on the period 1998 to 2009 on permanent transects established in 1987 and monitored periodically, partly as a contribution to the Global Coral Reef Monitoring Network (GCRMN). In general, community structures at both locations remained stable, with primary producer coverage around 5% at Toboggan (T) and around 60% at Planch'Alizés (P). Living coral coverage averaged around 17% at both sites, but it was dominated by Acropora on Site-T (68%) and by massive corals on Site-P (88%). Regular echinoids were very abundant at T but almost absent from P, while the opposite was true for holothurids. The territorial damselfish Stegastes was of comparable abundance at both sites (

The role of birds as reservoirs and disseminators of parasites and pathogens has received much attention over the past several years due to their high vagility. Seabirds are particularly interesting hosts in this respect. In addition to incredible long-distance movements during migration, foraging and prospecting, these birds are long-lived, site faithful and breed in dense aggregations in specific colony locations. These different characteristics can favor both the local maintenance and large-scale dissemination of parasites and pathogens. The Iles Eparses provide breeding and feeding grounds for more than 3 million breeding pairs of seabirds including at least 13 species. Breeding colonies on these islands are relatively undisturbed by human activities and represent natural metapopulations in which seabird population dynamics, movement and dispersal can be studied in relation to that of circulating parasites and pathogens. In this review, we summarize previous knowledge and recently-acquired data on the parasites and pathogens found in association with seabirds of the Iles Eparses. These studies have revealed the presence of a rich diversity of infectious agents (viruses, bacteria and parasites) carried by the birds and/or their local ectoparasites (ticks and louse flies). Many of these agents are widespread and found in other ecosystems confirming a role for seabirds in their large scale dissemination and maintenance. The heterogeneous distribution of parasites and infectious agents among islands and seabird species suggests that relatively independent metacommunities of interacting species may exist within the western Indian Ocean. In this context, we discuss how the patterns and determinants of seabird movements may alter parasite and pathogen circulation. We conclude by outlining key aspects for future research given the baseline data now available and current concerns in eco-epidemiology and biodiversity conservation., Highlights • Seabirds make up a major proportion of vertebrate biodiversity in the Iles Eparses. • Colonial breeding may favor the local transmission and spread of infectious agents. • A diversity of parasites and pathogens have been described within these colonies. • Patterns of infection are linked to seabird genetic structure and individual movements. • Future work is required to understand impacts on seabird dynamics and disease risk.

International audience; TAAF ensures since 2007 the management of 5 small tropical islands lying in the southwestern Indian Ocean: the Iles Eparses. These islands share an exceptional natural heritage including many marine and terrestrial endemic species. At a regional scale the Iles Eparses are some of the most pristine ecosystems, largely preserved from anthropogenic impacts due to their geographical isolation and a historically very limited human occupation. In this context, TAAF wished that Iles Eparses become unique natural laboratories for earth scientists and environmental process observation – like climate change impacts - but also sustainable biodiversity sanctuaries for which the scientific community should provide baseline ecological data to inform on appropriate conservation tools. An inter-agency research consortium emerged in 2009 to meet this commitment for the Iles Eparses. This program was intended to set a science framework in accordance with France' objectives for Research and Conservation. It enabled between 2009 and 2014 the implementation of 18 cross-disciplinary research projects ranging from geology to ecology and represented by the variety of the proposed articles in this special issue. Altogether research projects have dramatically increased knowledge on the Iles Eparses' ecosystems and have provided the first overview of their diversity, their functions and their dynamics and its determinants. In particular applied research efforts have supplied a significant amount of ecological evidence that is now available to develop optimal conservation strategy to ensure the Iles Eparses' long-term biodiversity value. These findings point out that the continuation of research activity in the Iles Eparses should be considered a priority.

Stomach contents and stable carbon and nitrogen isotope analyses (δ13C and δ15N) were used to investigate the trophic ecology of two apex predators, tiger sharks (Galeocerdo cuvier) and bull sharks (Carcharhinus leucas), from Reunion Island to describe their dietary habits at both the population and individual levels. In this oceanic island, the tiger and bull sharks were more piscivorous and teutophagous than noted in previous research from other localities. The δ13C values suggested that bull sharks depended on more neritic organic matter sources than tiger sharks, confirming a coastal habitat preference for bull sharks. Moreover, the total length of the bull shark influenced δ13C values, with smaller individuals being more coastal than larger individuals. All indicators suggest that there is a higher degree of similarity between individual tiger sharks compared with the more heterogeneous bull shark population, which is composed of individuals who specialize on different prey. These results suggest that the two species have different functions in these coastal habitats, and thus, they must be considered independently in terms of conservation and management.

International audience; We conducted a regional tracking program on seabirds in order to identify major forging hotspots and potential Marine Protected Areas in the tropical western Indian Ocean. Thirty-one species of seabirds breed in the region, totaling 7.4 million pairs. The main breeding grounds are in the Seychelles, in the Mozambique Channel and in the Mascarene. Seven pelagic species have been tracked so far from eight different islands of the region. Using count per sector analysis we identified five major oceanic foraging hotspots, among which three include the breeding colonies and two are oceanic areas not connected to a breeding island. We found important overlaps between most of these seabird foraging hotspots and potential threats (industrial fishery targeting surface dwelling tunas and marine pollution due to maritime routes) suggesting that in these regions seabirds may be at risk when foraging. Although this analysis is based on a limited number of tracking studies, the knowledge on seabird distribution at sea has increased tremendously in the last 6 years in the tropical western Indian Ocean, and this trend will continue, as research is ongoing. The data, we present here for the first time in a single synthesis show clear spatial patterns that identify high priority locations for designation as Marine Protected Areas in the tropical western Indian Ocean.

Two hypotheses have been proposed to explain sex-related differences in foraging in sexually monomorphic seabirds. The 'intersexual competition' hypothesis suggests that parents are in competition and that the dominated sex must adapt its behaviour to avoid competing with the dominant one. The 'energetic constraint' hypothesis suggests that differential energetic requirements lead to different foraging behaviour. We examined sexual differences in foraging behaviour of a sexually monomorphic tropical seabird, the Barau's petrel, Pterodroma baraui, throughout the breeding period. We found sexual differences in foraging habitats and activities, but these were not consistent throughout the breeding period. During the prelaying exodus, males foraged further from the colony, in waters with greater surface chlorophyll concentration, and were more active than females. Males systematically took the first incubation shift, which was always longer than the others. However, no sex-related differences in foraging behaviour were observed during the chick-rearing period, both sexes sharing parental duties equally. We suggest that the sexual differences observed early in the breeding period are due to the specific needs of males and females. Females need to restore their body condition as quickly as possible after laying, which forces males to take the first long incubation shift at the nest. This may explain why males forage more actively during the prelaying exodus, to prepare for this long fasting period. Our results support for the first time the 'energy constraint' hypothesis to explain sexual differences in behaviour of a small, monomorphic procellariiform seabird.

Sustainably managing ecosystems is challenging, especially for complex systems such as coral reefs. This study develops critical reference points for sustainable management by using a large empirical dataset on the coral reefs of the western Indian Ocean to investigate associations between levels of target fish biomass (as an indicator of fishing intensity) and eight metrics of ecosystem state. These eight ecological metrics each exhibited specific thresholds along a continuum of fishable biomass ranging from heavily fished sites to old fisheries closures. Three thresholds lay above and five below a hypothesized window of fishable biomass expected to produce a maximum multispecies sustainable yield ( B MMSY ). Evaluating three management systems in nine countries, we found that unregulated fisheries often operate below the B MMSY , whereas fisheries closures and, less frequently, gear-restricted fisheries were within or above this window. These findings provide tangible management targets for multispecies coral reef fisheries and highlight key tradeoffs required to achieve different fisheries and conservation goals.

Cats are generalist predators that have been widely introduced to the world's ~179 000 islands. Once introduced to islands, cats prey on a variety of native species many of which lack evolved defenses against mammalian predators and can suffer severe population declines and even extinction. As islands house a disproportionate share of terrestrial biodiversity, the impacts of invasive cats on islands may have significant biodiversity impacts. Much of this threatened biodiversity can be protected by eradicating cats from islands. Information on the relative impacts of cats on different native species in different types of island ecosystems can increase the efficiency of this conservation tool. We reviewed feral cat impacts on native island vertebrates. Impacts of feral cats on vertebrates have been reported from at least 120 different islands on at least 175 vertebrates (25 reptiles, 123 birds, and 27 mammals), many of which are listed by the International Union for the Conservation of Nature. A meta-analysis suggests that cat impacts were greatest on endemic species, particularly mammals and greater when non-native prey species were also introduced. Feral cats on islands are responsible for at least 14% global bird, mammal, and reptile extinctions and are the principal threat to almost 8% of critically endangered birds, mammals, and reptiles., This work has received support from the European Union by the projects CGL-2004-0161 BOS co-financed by the Spanish Ministry of Science and Education, the DIREN PACA via Life Nature project (ref. LIFE03NAT/F000105), the French National Research Agency (ALLIENS project) and the MEDAD (Ecotropic programme). EB was financed by a CR PACA PhD fellowship. Brian M. Fitzgerald made a critical read of this review, supporting interesting annotations and suggestions. Pedro Jordano made useful comments on the early draft of the manuscript, and Karl J. Campbell and an anonymous referee did it on its final stage.

The effect of decreasing aragonite saturation state (ΩArag) of seawater (elevated pCO2) on calcification rates of Acropora muricata was studied using nubbins prepared from parent colonies located at two sites of La Saline reef (La Réunion Island, western Indian Ocean): a back-reef site (BR) affected by nutrient-enriched groundwater discharge (mainly nitrate), and a reef flat site (RF) with low terrigenous inputs. Protein and chlorophyll a content of the nubbins, as well as zooxanthellae abundance, were lower at RF than BR. Nubbins were incubated at ~27°C over 2 h under sunlight, in filtered seawater manipulated to get differing initial pCO2 (1,440-340 μatm), ΩArag (1.4-4.0), and dissolved inorganic carbon (DIC) concentrations (2,100-1,850 μmol kg−1). Increasing DIC concentrations at constant total alkalinity (AT) resulted in a decrease in ΩArag and an increase in pCO2. AT at the beginning of the incubations was kept at a natural level of 2,193 ± 6 μmol kg−1 (mean ± SD). Net photosynthesis (NP) and calcification were calculated from changes in pH and AT during the incubations. Calcification decrease in response to doubling pCO2 relative to preindustrial level was 22% for RF nubbins. When normalized to surface area of the nubbins, (1) NP and calcification were higher at BR than RF, (2) NP increased in high pCO2 treatments at BR compared to low pCO2 treatments, and (3) calcification was not related to ΩArag at BR. When normalized to NP, calcification was linearly related to ΩArag at both sites, and the slopes of the relationships were not significantly different. The increase in NP at BR in the high pCO2 treatments may have increased calcification and thus masked the negative effect of low ΩArag on calcification. Removing the effect of NP variations at BR showed that calcification declined in a similar manner with decreased ΩArag (increased pCO2) whatever the nutrient loading.

The Abdur Archaeological Site was defined initially by the discovery and dating (125 +/− ka by Ur/Th) of in situ stone tools within uplifted marine terrace deposits located along the southern Red Sea coast of Eritrea, near the small village of Abdur. These tools represent some of the earliest well-dated evidence for human occupation of coastal marine environments. The site is located on the Buri Peninsula along the eastern shoreline of the Gulf of Zula and covers an area of approximately 7 km by 1 km. Three main stratigraphic units are defined and discussed from oldest to youngest: (1) The Buri Formation is defined herein as a sequence of brackish–freshwater (estuarine) and fluvial–deltaic sediments consisting of mudstones, siltstones, sandstones, conglomerates and limestones with ash and pumice beds. Ar–Ar dating of pumice and tephras puts the time of deposition of this unit from about 0.91 to 0.72 Ma (Early–Middle Pleistocene). Several stone tools were discovered in the Buri Formation, indicating early human occupation of a coastal environment during the Early to Middle Pleistocene. (2) The Abdur Volcanic Complex (AVC) is a small basaltic shield complex that forms the highlands along the eastern part of the Abdur Site and extends to the north and south of the area. Basalts from this center were dated from 2.12 to 0.17 Ma, indicating that the volcanic complex has been tectonically and magmatically active prior to, during and after deposition of the Buri Formation. (3) The Abdur Reef Limestone (ARL) is the remnant of a shallow marine reef system deposited approximately 125 ka (last glacial highstand, isotope stage 5e) along the margins of the Abdur volcanic highlands. The ARL consists of a basal transgressive lag deposit overlain by extensive buildups of mollusks, echinoderms, bioclastic sands and corals up to 11 m thick. Numerous stone tools in the ARL fall into two tool kits, bifacial hand axes of the Acheulian industry and Middle Stone Age-type (MSA) obsidian flakes and blades. Their distribution suggests that foraging activities of early humans varied with environmental setting. The Buri Formation has been folded and faulted prior to deposition of the ARL, with dips as high as 36° and vertical locally along fault zones. The ARL has been uplifted up to 8–15 m and tilted 1°–5° in a seaward direction. The area is cut by numerous faults, part of a regional NNW-trending fault system. Occurrences of Buri Formation equivalents to the north along the Buri Peninsula as well as in the area southwest of the Alid volcano suggest the area west of the escarpment was a broad lowland characterized by rivers, coastal lakes, and estuaries along the Red Sea coast during the Early to Middle Pleistocene. Reefs equivalent to the ARL covered large parts of the adjacent Buri Peninsula, the north end of Mt. Ghedem across the Gulf of Zula, and the Dahlak Archipelago to the north.

International audience; The White-tailed Tropicbird Phaethon lepturus breeding population of Aride Island, Seychelles, has experienced a strong decline in the recent past. To predict the future trends of the White-tailed Tropicbird population on Aride Island and understand the urgency of applying management procedures, we developed a population matrix model. We estimated White-tailed Tropicbird adult survival rate over a 12-year period and investigated whether oceanographic conditions (El Niño Southern Oscillation, ENSO, and inter-annual climate variability in the Indian Ocean, Indian Ocean Dipole, IOD) or local factors ( Pisonia grandis fruiting events) potentially affect adult survival. Annual adult survival could not be linked to inter-annual variability in oceanographic conditions, but may be more influenced by Pisonia fruiting events, which, overall, accounts for 23.2% of the adult mortality. The growth rate of the population, primarily influenced by annual adult survival, was estimated to be 0.946, which indicates an annual population decline of 5.4%. At the current rate, the probability of extinction of this population would be 99% in 170 years. Management scenarios studied through Monte Carlo simulations, assuming small increments in adult survival and/or breeding success, dramatically reduce the risk of extinction of White-tailed Tropicbirds. Habitat management, in order to maintain an open canopy and little understorey vegetation, appears to be crucial for the conservation of White-tailed Tropicbirds on Aride Island, as has already been shown for other ground-nesting tropical seabirds nesting on forested islands.

The Yelkouan shearwater, Puffinus yelkouan, is an endangered Mediterranean endemic species of burrowing petrel threatened by feral cats. The life-history parameters of a small population of Yelkouan shearwaters on the Mediterranean island, Port-Cros, were studied in conjunction with the diet of feral cats, to examine the birds' vulnerability to introduced cats. Yelkouan shearwaters were the birds most frequently found in cat scats, with 431 ± 72 birds killed per year, and predation highest during the pre-laying period. A demographic model was created using data for P. yelkouan and for closely related shearwater species. Without cat predation, only two of four survival rate scenarios led to a mean growth rate (λ) ≥ 1. The model was constrained to have a stable population growth rate and used to predict predation scenarios compatible with the observed population stability, because the population under study has remained stable at around 180 pairs for at least 20 years despite feral cat predation. The results of assuming that the population is closed were inconsistent with the estimated mortalities due to feral cats, while it was possible to reconcile the observed numbers of breeding pairs with the observed mortalities due to cats by assuming that Port-Cros Island is a sink sustained by immigration. This illustrates that small colonies may need to be sustained by larger ones to avoid being driven to extinction. Unfortunately, the absence of a large geographic-scale ringing program makes the precise identification of the origin of the immigrants impossible in this case.

The pan-European MacroBen database was used to compare the AZTI Marine Biotic Index (AMBI) and the Benthic Quality Index (BQIES), 2 biotic indices which rely on 2 distinct assessments of species sensitivity/tolerance (i.e. AMBI EG and BQI E[S]0.05) and which up to now have only been compared on restricted data sets. A total of 12 409 stations were selected from the database. This subset (indicator database) was later divided into 4 marine and 1 estuarine subareas. We computed E(S50)0.0 in 643 taxa, which accounted for 91.8% of the total abundances in the whole marine indicator database. AMBI EG and E(S50)0.05 correlated poorly. Marked heterogeneities in E(S50)0.0 between the marine and estuarine North Sea and between the 4 marine subareas suggest that sensitivity/tolerance levels vary among geographical areas. High values of AMBI were always associated with low values of BQIES, which underlines the coherence of these 2 indices in identifying stations with a bad ecological status (ES). Conversely, low values of AMBI were sometimes associated with low values of BQIES resulting in the attribution of a good ES by AMBI and a bad ES by BQIES. This was caused by the dominance of species classified as sensitive by AMBI and tolerant by BQIES. Some of these species are known to be sensitive to natural disturbance, which highlights the tendency of BQIES to automatically classify dominant species as tolerant. Both indices thus present weaknesses in their way of assessing sensitivity/tolerance levels (i.e. existence of a single sensitivity/tolerance list for AMBI and the tight relationship between dominance and tolerance for BQIES). Futurestudies should focus on the (1) clarification of the sensitivity/tolerance levels of the species identifiedas problematic, and (2) assessment of the relationships between AMBI EG and E(S50)0.05 within and between combinations of geographical areas and habitats.

International audience; ABSTRACT: This paper is a short review of recent literature on how ocean acidification may influence coral reef organisms and coral reef communities. We argue that it is unclear as to how, and to what extent, ocean acidification will influence calcium carbonate calcification and dissolution, and affect changes in community structure of present-day coral reefs. It is critical to evaluate the extent to which the metabolism of present-day reefs is influenced by mineral saturation states, and to determine a threshold saturation state at which coral communities cease to function as reefs.

Study of living colonies ofSalacia tetracytharaLamouroux, 1816, led to an accurate description of the hydranths and adjoining tissues. A mantle is reported for the first time for this species, lining stem, hydrocladia and hydrotheca. An adcauline nematocyst clump located in the median part of the column, composed of large microbasic mastigophores, is also reported as a new structure for sertulariids. The hypothetical modified tentacles noted by Billard (1925) are confirmed and re-described. Among the 22–28 tentacles of the hydranth in a circlet, two exhibit nematocyst-bearing organs connected at base. These organs are massive, racket-shaped, refringent, and composed of large microbasic mastigophores. They do not affect the tentacles in respect of their general shape and behaviour. One nematocyst-bearing organ can sometimes be linked to more than one tentacle depending on its size. The abcauline position of the two modified tentacles imparts a strong bilateral symmetry to the hydranth. This location explains why only one modified tentacle was previously described from preserved material, the second being hidden by the first when hydranths are retracted inside the hydrotheca. The modified tentacles ofS. tetracytharaare compared with the nematodactyls of the genusNemalecium, with the ligula found in several sertulariid species, and with nematophores described in other thecate families. Beside remarks on species taxonomy and distribution, incitation is given to the study, with emphasis especially on hydranths.

International audience; Nitrogen (δ15N) and carbon (δ13C) stable isotopes and contaminants, such as mercury, have been widely used to characterise foraging ecology of temperate and polar seabirds. In this study, for the first time, we used isotopic signatures and mercury levels of feathers and blood of eight tropical seabird species, that forage in a range-gradient between inshore and offshore areas, to describe the foraging habits of a large tropical seabird community (from two neighbouring islands of the Seychelles archipelago, western Indian Ocean) during both the breeding and interbreeding periods. Overall, we found a high overlap in both δ15N and δ13C signatures among species. The high interspecific overlap in δ15N values was expected, given the similarities in the diet of the species from this community. However, several unexpected results, such as (1) the consistently higher δ15N signatures of white terns (Gygis alba), (2) the large variation in inter-specific differences in δ15N signatures among the sampling groups (season, age, island and tissue) and (3) the consistent low δ15N values of breeding birds during the northwest monsoon (austral summer), suggest that δ15N signatures cannot be used as indicators of seabird trophic levels in this community. The high interspecific overlap in δ13C signatures and the absence, during the breeding season, of a δ13C gradient that follows the inshore-offshore foraging gradient within the community can be explained by the habitat homogeneity of the Seychelles continental shelf and suggest that birds forage mostly within the limits of this "plateau". On the other hand, the similarities in δ13C values between the breeding and inter-breeding periods in species that are known to show post-breeding dispersal, strongly support the hypothesis of a lack of latitudinal variation in δ13C signatures of POM in the central Indian Ocean, and the consequent inaccuracy of δ13C values to track seabird movements within this geographic area. Inter-specific differences in mercury levels seem to be related to prey size, while consistent higher mercury concentrations in one of the studied islands suggest different island mercury-backgrounds and possible segregation in foraging areas between the seabirds of the two islands.

The ability of the two synthetic marine biotic indices, AMBI and M-AMBI, to account for changes in the ecological quality of coastal soft bottoms of Reunion Island according to disturbances was assessed from macrobenthic samples collected in five sectors between 1994 and 2004. Samples were collected under non-perturbed conditions and at two sites subjected to heavy organic enrichment. Both indices are based on a classification of macrofauna into ecological groups (EG), and their transfer to tropical waters required some adaptations. These indices proved efficient in detecting a degradation of habitat quality. Their use resulted in the classification of all sites sampled between 1996 and 1998 as "good" or "high". M-AMBI nevertheless tended to result in the attribution of a slightly worse ecological quality status than AMBI. Together with an update of the EG species list for the Indian Ocean area, our results support the extension of both indices for the assessment of tropical soft bottoms.

The western Indian Ocean supports over 6 200 000 pairs of Sooty Terns, some in very large colonies. During the past two centuries colonies have exhibited increase, stability, decline and extinction. The main drivers of these trends have been habitat change and unregulated human exploitation, especially of adults; introduced predators appear to have little effect at the population level but may have prevented re-colonisation following habitat restoration. Regulated harvesting of eggs, based on increasing knowledge of Sooty Tern demography, appears to be sustainable. Some colonies now receive protection but it will be logistically difficult to extend this to all colonies. The main future threats are likely to be climate change and over-exploitation of tuna, on which Sooty Terns depend to feed. Sooty Terns should be monitored to provide insights into these and other perturbations of the marine ecosystem.Ostrich 2007, 78(2): 423–434

International audience; Food availability, which is often seasonal, is regarded as a key factor in the breeding success of seabirds. In oceanic tropical areas, the resources are mostly patchy and ephemeral at the surface, and the seasonality is less marked than at higher latitudes. Such a situation influences greatly the breeding strategies of the oceanic seabird species. We conducted a comparative study of the breeding phenology of the sooty tern (Sterna fuscata) in relation to the local and regional oceanographic conditions around the four major colonies (Europa, Juan de Nova, Lys and Bird Islands) of the southwest Indian Ocean. Over the 1997–2003 period, around all the studied locations, the sea-surface temperature (SST) and the chlorophyll concentration in the Mozambique Channel and the Seychelles area showed clear seasonal differences related to the southern climate and the monsoon phenomena. The breeding activity is synchronized at each studied colony, but the timings are very different. Seasonal reproduction occurs in austral winter at Europa and Bird Island and in austral summer at Juan de Nova; at Lys Island the reproduction is non-seasonal. For the seasonal colonies, there is a large monthly change in SST just before the beginning of reproduction, which is a proxy indicating the annual phytoplankton bloom. This variation is accompanied by the development of oceanic features such as fronts that favour aggregation of prey, and may also play an important role in the presence of schools of surface tuna, which are very important for the foraging success of sooty terns. Conversely, around Lys Island the seasonal variations of the marine environment do not lead to pronounced development of oceanic structures, and consequently, the longer-lasting phytoplankton bloom could explain the non-seasonal breeding regime there. Further studies will help discern the advantages and disadvantages of seasonal and non-seasonal reproduction regime in response to unpredictable fluctuations of the marine environment.

International audience; To refine our understanding of the spatial structure of the green turtle (Chelonia mydas) populations in the South West Indian Ocean (SWIO), we analysed patterns of mitochondrial DNA (396 base pairs control region fragment) variation among 171 samples collected at five distinct locations (Kenya, Northern Mozambique, and three locations in the Republic of Seychelles: the Granitic, Amirantes, and Farquhar groups) and compared them to genetic data (n = 288), previously collected from 10 southern locations in the SWIO. We also analysed postnesting satellite tracks (n = 4) from green turtles nesting in the Amirantes group. Pairwise comparisons of haplotype frequencies showed significant genetic differentiation amongst rookeries and suggest that the SWIO hosts two main genetic stocks of nesting green turtles that could themselves be divided in two sub-stocks that still need to be confirmed: A. the Southern Mozambique Channel, that could be composed of two sub-stocks (a1) Europa and (a2) Juan de Nova, and B. the Northern SWIO (N-SWIO) comprising two sub-stocks (b1) the Seychelles archipelago stock—SEY; and (b2) the remaining Northern SWIO rookeries. The newly revealed differentiation of the Seychelles population is supported by restricted migration of females tracked from the Amirantes group suggesting relatively limited links with other regional stocks. We hypothesize that this differentiation could be due to local and regional current patterns and to the role of the Indo-Pacific Barrier as a genetic break, enhanced during periods of sea level decrease associated with a rare but continuous flow of hatchlings and young juveniles from Western Australia.

This note describes the first record of the chocolate shrimp-goby Cryptocentrus malindiensis (Smith, 1959) from Réunion island, based on photographic evidence. A specimen of an estimated total length of 7 cm was photographed at 9:00 AM on 8 November 2012, at a water temperature of 26°C and depth of 8 m, on a prehistoric lava flow of the Piton de la Fournaise volcano. The habitat included shallow-water sea cracks and rocky overhangs, near basaltic muddy sandy bottoms, with a high hard substrate cover of calcareous algae, encrusting sponges and hydroids without coral, reflecting a low-light environment at these latitudes. Significant siltation, probably caused by a nearby river mouth, suggested the presence of a relatively low wave and current energy, which could be the effect of the confined nature of the habitat., Cette note présente le premier signalement du gobie de Malindi Cryptocentrus malindiensis (Smith, 1959) à la Réunion, sur la base de preuves photographiques. Un spécimen d’une longueur totale d’environ 7 cm a été photographié à 9:00, le 8 novembre 2012, par 8 m de profondeur, dans une eau à 26°C, sur une coulée de lave préhistorique du Piton de la Fournaise. L’habitat se composait de failles et de surplombs rocheux peu profonds, près de fonds sablo-vaseux basaltiques, avec un recouvrement important des substrats durs par les algues calcaires, les éponges encroûtantes et les hydraires, témoignant sous ces latitudes d’un environnement à faible luminosité. Un envasement significatif, probablement généré par la proximité d’une embouchure de rivière, suggère la présence de conditions hydrodynamiques modérées, qui pourraient être dues à la nature confinée de l’habitat.

International audience; This note describes the first record of the chocolate shrimp-goby Cryptocentrus malindiensis (Smith, 1959) from Réunion island, based on photographic evidence. A specimen of an estimated total length of 7 cm was photographed at 9:00 AM on 8 November 2012, at a water temperature of 26°C and depth of 8 m, on a prehistoric lava flow of the Piton de la Fournaise volcano. The habitat included shallow-water sea cracks and rocky overhangs, near basaltic muddy sandy bottoms, with a high hard substrate cover of calcareous algae, encrusting sponges and hydroids without coral, reflecting a low-light environment at these latitudes. Significant siltation, probably caused by a nearby river mouth, suggested the presence of a relatively low wave and current energy, which could be the effect of the confined nature of the habitat.; Cette note présente le premier signalement du gobie de Malindi Cryptocentrus malindiensis (Smith, 1959) à la Réunion, sur la base de preuves photographiques. Un spécimen d’une longueur totale d’environ 7 cm a été photographié à 9:00, le 8 novembre 2012, par 8 m de profondeur, dans une eau à 26°C, sur une coulée de lave préhistorique du Piton de la Fournaise. L’habitat se composait de failles et de surplombs rocheux peu profonds, près de fonds sablo-vaseux basaltiques, avec un recouvrement important des substrats durs par les algues calcaires, les éponges encroûtantes et les hydraires, témoignant sous ces latitudes d’un environnement à faible luminosité. Un envasement significatif, probablement généré par la proximité d’une embouchure de rivière, suggère la présence de conditions hydrodynamiques modérées, qui pourraient être dues à la nature confinée de l’habitat.

International audience; Rats contribute to the decline of tropical seabird populations by affecting their breeding success through direct predation of eggs and chicks. When they coexist with other predators, invasive rats may also generate indirect interactions via the changes they impose on the structure of communities and trophic interactions following invasion (‘hyperpredation process’), or when apex predators are eradicated fromthe ecosystem (‘mesopredator release effect’). Understanding these effects is necessary to implement restoration operations that actually benefit threatened seabird populations. We investigated these processes on two French tropical seabird islands of the western Indian Ocean, Europa and Juan de Nova, where black rats coexist with two different apex predator species (introduced cats and potentially native barn owls). The parallel use of several methods (diet analysis, stable isotopes, seabird monitoring) to identify trophic roles of rats revealed that the direct impact of rats on seabirds was particularly high on Europa where only rats and owls occur, with high consumption of chicks resulting in low breeding success for several seabird species. We also suggested that hyperpredation associated with top-down regulation of cats is occurring on Juan de Nova, although territoriality of cats may buffer this process. Conversely we found evidence that mesopredator release effect is unlikely, irrespective of the apex predator identity. Considering the most likely effects on both islands we provided recommendations on eradication priorities to mitigate the risk of local extinction that seabirds are currently facing.

Contractualisation Ifremer/Office de l'eau Réunion. Synthèse collective des travaux menés dans le cadre des Groupes de travail DCE de La Réunion réunissant des experts de l'Université de La Réunion (Lab. ECOMAR), de l'IRD de La Réunion, de l'ARVAM, de PARETO, du GIP RNMR et de la DEAL Réunion sous la coordination de la Délégation Ifremer océan Indien. Comment citer ce document : GT DCE Réunion "Physico-Chimie & Phytoplancton". 2015. Fascicule technique pour la mise en œuvre du suivi " Physico-Chimie & Phytoplancton" du réseau de contrôle de surveillance DCE à La Réunion : Réseau Hydrologique du Littoral Réunionnais.Convention Ifremer/Office de l'Eau Réunion n° 14/1211501/F. http://archimer.ifremer.fr/doc/00168/27915/; International audience; De 2010 à 2012, le projet " Bon Etat : Actualisation de l’état des lieux du SDAGE, volet eaux côtières réunionnaises " (DEAL de La Réunion/Ifremer) a permis la mise en place de 4 groupes de travail DCE experts dont les travaux ont été synthétisés à travers 4 fascicules techniques définissant les conditions de mise en œuvre des différents suivis du réseau de contrôle de la surveillance (RCS) DCE en milieu marin à la Réunion. Une première version du fascicule "Physico-chimie & phytoplancton", a été produite en 2012 et validée au niveau national par les référents DCE (Coordination "phytoplancton", Coordination "hydrologie", Coordination nationale DCE milieu Marin, responsable projet Quadrige). Une mise à jour a été proposée en 2015 (Office de l'eau Réunion/Ifremer) dans la double perspective des recommandations du GT DCE de la Réunion et des nouvelles campagnes de suivi du "Réseau Hydrologique du Littoral Réunionnais - RHLR". Ce fascicule a vocation à constituer le support technique des méthodes et des référentiels pour la réalisation du suivi "RHLR" du RCS DCE à La Réunion. Il précise les protocoles de prélèvement, d’analyse, de bancarisation, de synthèse et de diffusion des données. Il présente également les indicateurs associés aux différents éléments de qualité, adaptés à La Réunion.

International audience; The active selection of recent volcanic habitats by juvenile fish following a cyclone could explain the unusual mass-settlement of the Indian Ocean blacktip grouper Epinephelus oceanicus observed on 25 May 2006, few weeks after tropical storm Diwa on the latest lava flows of the Piton de la Fournaise volcano at Reunion Island. Following a cyclonic depression, shallow underwater habitats are devoid of resident fishes, including predators, favouring juvenile fish survival. Otherwise, the recent origin of the volcanic habitats, which vary in age, could facilitate the spatial segregation of adult and juvenile fish on the lava flows, reducing intraspecific competition and adult aggression toward juveniles. Regional characteristics of larval recruitment could also contribute to the infrequency of the described event; the isolated situation of the island would be expected to result in an average density of fish postlarvae 0.25 % to 1 % of that seen on some reefs in the Pacific. The supposed origin of juvenile groupers in the neighbouring island of Mauritius should encourage Reunionese managers to look beyond their own jurisdictions to adopt a collaborative approach to conservation of the entire connected network.