Éditeur(s) : HAL CCSD European Geosciences Union (EGU)
Résumé : International audience
Storms and tsunamis, which may seriously endanger human society, are amongst the most devastating marine catastrophes that can occur in coastal areas. Many such events are known and have been reported for the Mediterranean, a region where high-frequency occurrences of these extreme events coincides with some of the most densely populated coastal areas in the world. In a sediment core from the Mar Menor (SE Spain), we discovered eight coarse-grained layers which document marine incursions during periods of intense storm activity or tsunami events. Based on radiocarbon dating, these extreme events occurred around 5250, 4000, 3600, 3010, 2300, 1350, 650, and 80 years cal BP. No comparable events have been observed during the 20th and 21st centuries. The results indicate little likelihood of a tsunami origin for these coarse-grained layers, although historical tsunami events are recorded in this region. These periods of surge events seem to coincide with the coldest periods in Europe during the late Holocene, suggesting a control by a climatic mechanism for periods of increased storm activity. Spectral analyses performed on the sand percentage revealed four major periodicities of 1228 ± 327, 732 ± 80, 562 ± 58, and 319 ± 16 years. Amongst the well-known proxies that have revealed a millennial-scale climate variability during the Holocene, the ice-rafted debris (IRD) indices in the North Atlantic developed by Bond et al. (1997, 2001) present a cyclicity of 1470 ± 500 years, which matches the 1228 ± 327-year periodicity evidenced in the Mar Menor, considering the respective uncertainties in the periodicities. Thus, an in-phase storm activity in the western Mediterranean is found with the coldest periods in Europe and with the North Atlantic thermohaline circulation. However, further investigations, such as additional coring and high-resolution coastal imagery, are needed to better constrain the main cause of these multiple events.
ISSN: 1814-9324

hal-01357199
https://hal.archives-ouvertes.fr/hal-01357199
https://hal.archives-ouvertes.fr/hal-01357199v2/document
https://hal.archives-ouvertes.fr/hal-01357199/file/cp-12-1389-2016.pdf
DOI : 10.5194/cp-12-1389-2016

Éditeur(s) : HAL CCSD Wiley Open Access
Résumé : International audience
Coral disease outbreaks have increased over the last three decades, but their causal agents remain mostly unclear (e.g., bacteria, viruses, fungi, protists). This study details a 14-month-long survey of coral colonies in which observations of the development of disease was observed in nearly half of the sampled colonies. A bimonthly qPCR method was used to quantitatively and qualitatively evaluate Symbiodinium assemblages of tagged colonies, and to detect the presence of Vibrio spp. Firstly, our data showed that predisposition to disease development in general, and, more specifically, infection by Vibrio spp. in Acropora cytherea depended on which clades of Symbiodinium were harbored. In both cases, harboring clade D rather than A was beneficial to the coral host. Secondly, the detection of Vibrio spp. in only colonies that developed disease strongly suggests opportunistic traits of the bacteria. Finally, even if sporadic cases of switching and probably shuffling were observed, this long-term survey does not suggest specific-clade recruitment in response to stressors. Altogether, our results demonstrate that the fitness of the coral holobiont depends on its initial consortium of Symbiodinium, which is distinct among colonies, rather than a temporary adaptation achieved through acquiring different Symbiodinium clades.
ISSN: 2045-7758

hal-01346931
https://hal-uvsq.archives-ouvertes.fr/hal-01346931
https://hal-uvsq.archives-ouvertes.fr/hal-01346931/document
https://hal-uvsq.archives-ouvertes.fr/hal-01346931/file/2016%20Rouze%20EcolEvol.pdf
DOI : 10.1002/ece3.1895

Éditeur(s) : HAL CCSD PeerJ
Résumé : International audience
Crustose coralline algae (CCA) are major benthic calcifiers that play crucial roles in marine ecosystems, particularly coral reefs. Over the past two decades, epizootics have been reported for several CCA species on coral reefs worldwide. However, their causes remain often unknown in part because few studies have investigated CCA pathologies at a microscopic scale. We studied the cellular changes associated with two syndromes: Coralline White Band Syndrome (CWBS) and Coralline White Patch Disease (CWPD) from samples collected in Curaçao , southern Caribbean. Healthy-looking tissue of diseased CCA did not differ from healthy tissue of healthy CCA. In diseased tissues of both pathologies, the three characteristic cell layers of CCA revealed cells completely depleted of protoplasmic content, but presenting an intact cell wall. In addition, CWBS showed a transition area between healthy and diseased tissues consisting of cells partially deprived of protoplasmic material, most likely corresponding to the white band characterizing the disease at the macroscopic level. This transition area was absent in CWPD. Regrowth at the lesion boundary were sometimes observed in both syndromes. Tissues of both healthy and diseased CCA were colonised by diverse boring organisms. Fungal infections associated with the diseased cells were not seen. However, other bioeroders were more abundant in diseased vs healthy CCA and in diseased vs healthy-looking tissues of diseased CCA. Although their role in the pathogenesis is unclear, this suggests that disease increases CCA susceptibility to bioerosion. Further investigations using an integrated approach are needed to carry out the complete diagnosis of these diseases.
ISSN: 2167-8359

Droits : http://creativecommons.org/licenses/by/
hal-01174251
https://hal-univ-perp.archives-ouvertes.fr/hal-01174251
https://hal-univ-perp.archives-ouvertes.fr/hal-01174251/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01174251/file/peerj-1034.pdf
DOI : 10.7717/peerj.1034

Éditeur(s) : HAL CCSD Elsevier
Résumé : Understanding the pattern in spatial distribution of soil microbial processes is critical to understand the environmental factors that regulate them as well as to scale up these processes to ecosystem. Soil samples from a I ha tropical rainforest plot (Paracou, French Guiana) were analyzed according a nested sampling approach using different separation distances ranging from 0.4 to 40 m. The variability of substrate induced respiration (SIR) and of denitrification enzyme activity (DEA) was characterized in relation to various soil properties (total C and N contents, NIRS related index of soil organic matter quality, SOMQ and index of tree influence potential, IP). The variability of SIR and DEA was higher than that of environmental properties. The patterns of accumulated variance as a function of distance varied among the soil properties. The variability of SIR and DEA mainly occurred at small (1 m) scale (and at the 10-40 m-scales for SIR), probably reflecting the quality of litter input that results of the influence of local assemblage of different tree species, though changes in the soil N and C contents. Indeed, total soil C and N contents explained the microbial properties at every scale. Coefficients of codispersion showed that neither SOMQ nor IP did correlate with SIR and DEA, and confirmed that total C and N contents explained microbial properties in a scale dependent and complex manner. Such spatial dependency underlines the importance of soil heterogeneity in this tropical forest with implications for sampling strategies when studying the microbial processes and their response to disturbances. (C) 2012 Elsevier B.V. All rights reserved.
ISSN: 0016-7061

hal-01032409
https://hal.archives-ouvertes.fr/hal-01032409
DOI : 10.1016/j.geoderma.2012.12.009

Éditeur(s) : HAL CCSD Magnolia Press
Résumé : International audience
A new species of the genus Cocconeis is described. Cocconeis sawensis sp. nov. was observed as epiphyte on the macrophyte Chara Linn. sp., collected from a saline lake in Iraq (Sawa Lake). Description of the new species is based on details observed with light and scanning electron microscopy. Cocconeis sawensis belongs to a group of taxa similar to Cocconeis euglypta Ehrenberg, but differs in a number of fine ultrastructural features including stria density and hymenes, raphe, valve shape and rim, valvocopula, hymen perforations and fimbriae shape as well as a presence of a pore-like structure reminiscent of a vestigial raphe in the sternum valve. A comparison with closely related taxa is given.
ISSN: 1179-3155

hal-01296895
https://hal-univ-perp.archives-ouvertes.fr/hal-01296895
DOI : 10.11646/phytotaxa.181.4.2

Éditeur(s) : HAL CCSD Czech Phycological Society
Résumé : International audience
As first observed on a group of taxa related to Cocconeis peltoides Hustedt, several other Cocconeis eHRenbeRG (Bacillariophyta) taxa possess a row of minute marginal pores on the external side of their sternum valve (SV) connected to small and simple internal portules, or processes. These processes are often located in continuity with the striae, but can also be slightly shifted or distant from the distal areola of the striae. The row of pores is often, but not always, externally separated from the stria by a crista marginalis. Within Cocconeis, and possibly all raphid diatoms, these processes seem unique and restricted to a few taxa. A list is presented of the taxa pertaining (or close) to Cocconeis that are actually known to share these micro–structures. In addition, the morphological variability of the processes is described in detail and a morphological comparison of the taxa is provided. The characteristic features of taxa showing a row of SV processes permit the tentative definition of several morphological groups. It is difficult to prove the taxonomic affiliation of these taxa and demonstrate or refute that these processes are ancestral characters. Some of these taxa are rare and restricted to low latitudes (e.g., tropical taxa) while others are frequent and ubiquitous. Abbreviations: (LM) light microscope, (SEM) scanning electron microscope, (RV) raphe valve, (SV) sternum valve, (RVVC) raphe valve valvocopula, (SVVC) sternum valve valvocopula
ISSN: 1802-5439

hal-01212883
https://hal-univ-perp.archives-ouvertes.fr/hal-01212883
https://hal-univ-perp.archives-ouvertes.fr/hal-01212883/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01212883/file/fottea_fot-201502-0003.pdf
DOI : 10.5507/fot.2015.015

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Based on new photographs of the wound, Tirard et al. (2015) tried to demonstrate that the shark involved in a fatal attack on a human in Lifou in 2007 had homodont teeth and that it sawed the femur instead of directly cutting it, promoting the hypothesis that it was a tiger shark instead of a white shark. They also contested the data provided by the direct witness of the attack about the behaviour of the shark, specific to this former species. The evidences they provide are not convincing and, based on the absence of tissue loss and description of a jumping behaviour, we still believe that it was a single bite-and-spit attack by a white shark.
ISSN: 1752-928X

hal-01310536
https://hal-univ-perp.archives-ouvertes.fr/hal-01310536
DOI : 10.1016/j.jflm.2016.03.004

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Increasingly frequent severe coral bleaching is among the greatest threats to coral reefs posed by climate change. Global climate models (GCMs) project great spatial variation in the timing of annual severe bleaching (ASB) conditions; a point at which reefs are certain to change and recovery will be limited. However, previous model-resolution projections (~1 × 1°) are too coarse to inform conservation planning. To meet the need for higher-resolution projections, we generated statistically downscaled projections (4-km resolution) for all coral reefs; these projections reveal high local-scale variation in ASB. Timing of ASB varies >10 years in 71 of the 87 countries and territories with >500 km 2 of reef area. Emissions scenario RCP4.5 represents lower emissions mid-century than will eventuate if pledges made following the 2015 Paris Climate Change Conference (COP21) become reality. These pledges do little to provide reefs with more time to adapt and acclimate prior to severe bleaching conditions occurring annually. RCP4.5 adds 11 years to the global average ASB timing when compared to RCP8.5; however, >75% of reefs still experience ASB before 2070 under RCP4.5. Coral reef futures clearly vary greatly among and within countries, indicating the projections warrant consideration in most reef areas during conservation and management planning.
ISSN: 2045-2322

hal-01441969
https://hal-univ-perp.archives-ouvertes.fr/hal-01441969
https://hal-univ-perp.archives-ouvertes.fr/hal-01441969/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01441969/file/local%20scale.pdf
DOI : 10.1038/srep39666

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
The present study tested different sounds that could disturb eagle rays (Aetobatus ocellatus) during their foraging activities at Moorea, French Polynesia. Results showed that artificial white sound and single-frequency tones (40 Hz, 600 Hz or 1 kHz) did not have an effect on rays (at least 90% of rays continued to forage over sand), while playbacks of boat motor sound significantly disturbed rays during foraging activity (60% exhibited an escape behaviour). Overall, our study highlighted the negative effect of boat noises on the foraging activity of eagle rays. These noises produced by boat traffic could, however, have some positive effects for marine aquaculture if they could be used as a deterrent to repel the eagle rays, main predators of the pearl oysters.
Notre étude teste différents types de sons qui pourraient perturber les raies-aigles (Aetobatus ocellatus) pendant leur prise de nourriture dans le lagon de Moorea, en Polynésie française. Les résultats montrent que le bruit artificiel blanc ou des fréquences uniques (40 Hz, 600 Hz ou 1 kHz) n’ont aucun effet sur les raies (au moins 90 % des raies continuent de se nourrir dans le sable), tandis que l’enregistrement d’un moteur de bateau les perturbe significativement dans cette activité (60 % des individus ont un comportement de fuite). Notre étude met ainsi en évidence l’effet négatif des bruits anthropogéniques sur les activités de nourrissage des raies-aigles. Ces bruits produits par les bateaux pourraient néanmoins avoir un effet positif pour l’aquaculture marine s’ils pouvaient être utilisés comme répulsifs des raies, principaux prédateurs de l’huître perlière.
ISSN: 1631-0691

Droits : http://creativecommons.org/licenses/by-nc-nd/
hal-01297683
https://hal-univ-perp.archives-ouvertes.fr/hal-01297683
https://hal-univ-perp.archives-ouvertes.fr/hal-01297683/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01297683/file/1-s2.0-S1631069116000020-main.pdf
DOI : 10.1016/j.crvi.2016.01.001

Éditeur(s) : HAL CCSD
Résumé : International audience
International Coral Reef Symposium 2012

hal-01429056
https://hal.archives-ouvertes.fr/hal-01429056

Éditeur(s) : HAL CCSD Laboratoire Arago
Résumé : International audience
The analysis of the C-O stable isotope composition of coral reef fish otoliths from Taiaro, a French Polynesian atoll normally isolated from the Pacific Ocean, has been performed to address two main questions. The first is to confirm previous results which suggest that a lagoonal coral reef fish population is able to achieve its ontogenetic cycle without any open ocean phase. If so, are O isotopic values of otoliths an indicator of temperature fluctuations in the tropical Pacific Ocean related to climate change and in particular temperature variations of water masses? δ18O and δ13C values on both lagoon and open ocean fish otoliths caught in 2006 indicated clearly that O-isotopes reached the isotopic equilibrium; in contrast, all δ13C values exhibited a strong isotopic disequilibrium related to metabolic activity. Stable isotope compositions revealed a clear differentiation between fish from lagoons and those from the open ocean (with a δ18O enrichment of 1 ‰ in favour of the lagoon). This confirmed a lack of connectivity between habitats and that fish from lagoon lived their entire life cycle in the lagoon. Both δ18O and δ13C data indicated differences between nucleus and edge signatures with changes in fish behavior from the larval life to adulthood (habitat, diet, etc.), and a clear adaptation of dietary behavior of lagoon fish. The comparison of the 2006 data set with those of 1994 showed that environmental conditions were stable in the lagoon, leading to a very narrow range of variations in the δ18O values. δ18O of fish otoliths of the open ocean exhibited a wider variation (+0.25 ‰) between 1994 and 2006, suggesting a decrease in temperature linked to a change of SST, which can be interpreted in terms of climate change associated with El Nino Southern Oscilation (ENENSO). These differences could also be due to a switch of habitats during the life cycle of fish from the open ocean.
ISSN: 0240-8759

hal-01162477
https://hal-univ-perp.archives-ouvertes.fr/hal-01162477

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: Color polymorphism in the nacre of pteriomorphian bivalves is of great interest for the pearl culture industry. The nacreous layer of the Polynesian black-lipped pearl oyster Pinctada margaritifera exhibits a large array of color variation among individuals including reflections of blue, green, yellow and pink in all possible gradients. Although the heritability of nacre color variation patterns has been demonstrated by experimental crossing, little isknown about the genes involved in these patterns. In this study, we identify a set of genes differentially expressed among extreme color phenotypes of P. margaritifera using a suppressive and subtractive hybridization (SSH) method comparing black phenotypes with full and half albino individuals.Results: Out of the 358 and 346 expressed sequence tags (ESTs) obtained by conducting two SSH libraries respectively, the expression patterns of 37 genes were tested with a real-time quantitative PCR (RT-qPCR) approach by pooling five individuals of each phenotype. The expression of 11 genes was subsequently estimated for each individual in order to detect inter-individual variation. Our results suggest that the color of the nacre is partiallyunder the influence of genes involved in the biomineralization of the calcitic layer. A few genes involved in the formation of the aragonite tablets of the nacre layer and in the biosynthesis chain of melanin also showed differential expression patterns. Finally, high variability in gene expression levels were observed within the black phenotypes.Conclusions: Our results revealed that three main genetic processes were involved in color polymorphisms: the biomineralization of the nacreous and calcitic layers and the synthesis of pigments such as melanin, suggesting that color polymorphism takes place at different levels in the shell structure. The high variability of gene expression found within black phenotypes suggests that the present work should serve as a basis for future studies exploringmore thoroughly the expression patterns of candidate genes within black phenotypes with different dominant iridescent colors.
ISSN: 1471-2164

hal-01260141
https://hal.archives-ouvertes.fr/hal-01260141
https://hal.archives-ouvertes.fr/hal-01260141/document
https://hal.archives-ouvertes.fr/hal-01260141/file/Lemer-2015-BMCGenom-Identification.pdf
DOI : 10.1186/s12864-015-1776-x

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We sought transversotrematid trematodes from French Polynesian fishes by examining 304 individual scaled fishes of 53 species from seven families known to harbour the family elsewhere. A single species was found at two locations in the Tuamotus Archipelago on two species of Chaetodontidae (Chaetodon auriga and Chaetodon ephippium) and one species of Lutjanidae (Lutjanus gibbus). The species closely resembles Transversotrema borboleta Hunter & Cribb, 2012 from chaetodontids and lutjanids of the northern Great Barrier Reef (GBR) but differs from it consistently in 8 base positions of ITS2 rDNA. This level of variation exceeds that between some clearly morphologically distinct pairs of species of Transversotrema and the form from French Polynesia is thus interpreted as a distinct, though cryptic, species and named Transversotrema polynesiae n. sp. The new species forms part of a complex of species, here characterised as the T. borboleta complex, associated with chaetodontids and lutjanids in the tropical Indo-West Pacific. Most of the putative species within this complex are yet to be described. Comparison of identical numbers of matched samples of fishes from French Polynesia, Heron Island (southern GBR) and Lizard Island (northern GBR) revealed 1, 4 and 10 species of Transversotrema respectively suggesting that the French Polynesian fauna is depauperate for this family. In addition to those species apparently missing from suitable hosts in French Polynesia, several species from further west infect fishes (especially Nemipteridae) that are themselves absent from French Polynesia. This dramatic east–west decline in richness contrasts strongly with what is known for monogeneans, which appear to maintain their richness over the same scale, and is more precipitate than is known for other groups of trematodes. The decline might be explained in part by the absence of the as yet unknown first intermediate hosts in French Polynesia. However, we predict that it is explained by other life cycle traits. We hypothesise that the characters of large short-lived cercariae, short-lived miracidia, the absence in the life-cycle of second intermediate hosts that are capable of transporting the species, and definitive and first intermediate hosts that have limited vagility combine to give marine Transversotrematidae limited dispersal capacity and a propensity for localised speciation.
ISSN: 1383-5769

hal-01333467
https://hal-univ-perp.archives-ouvertes.fr/hal-01333467
DOI : 10.1016/j.parint.2013.11.009

Éditeur(s) : HAL CCSD
Résumé : International audience
Sharks International
Durban, South Africa

hal-01487162
http://hal.univ-reunion.fr/hal-01487162

Éditeur(s) : HAL CCSD Royal Society, The
Résumé : International audience
Individuals can play different roles in maintaining connectivity and socialcohesion in animal populations and thereby influence population robustnessto perturbations.We performed a social network analysis in a reef shark populationto assess the vulnerability of the global network to node removal underdifferent scenarios. We found that the network was generally robust to theremoval of nodes with high centrality. The network appeared also highlyrobust to experimental fishing. Individual shark catchability decreased as afunction of experience, as revealed by comparing capture frequency and sitepresence. Altogether, these features suggest that individuals learnt to avoidcapture, which ultimately increased network robustness to experimentalcatch-and-release. Our results also suggest that some caution must be takenwhen using capture–recapture models often used to assess population sizeas assumptions (such as equal probabilities of capture and recapture) maybe violated by individual learning to escape recapture.
EISSN: 1471-2954

hal-01561754
https://hal-univ-perp.archives-ouvertes.fr/hal-01561754
DOI : 10.1098/rsbl.2016.0824

Éditeur(s) : HAL CCSD
Résumé : International audience
In most rock mechanical testing devices, the texture developed during deformation is only observed after the failure, and the detailed mapping of cracks and pore structure evolution, just before or after rupture, remains speculative. Computerized X-ray tomography (CT X-ray) offers a way to observe 'in vivo' some characteristics of a tested sample in the course of its deformation. Therefore we developed an X-ray transparent tri-axial cell that was included in a medical purpose X-ray scanner with a volumetric resolution of the order of 1 mm3. This technique is described and applied to a porous calcarenite, which is regularly scanned for porosity evolution during mechanical testing. The experiment is performed at low confining pressure (2-10 MPa). During testing, an axial load is applied until failure and is then progressively decreased. In these experiments, the peak stress is preceded by phase of diffuse dilatancy. After failure localization, the axial stress is unloaded until the stress reaches isotropy. During this unloading phase, the previous diffuse dilatancy is lost due to an elastic relaxation. Then, the stress is completely relaxed. At this moment the dilatancy increases again and the residual dilatancy is larger than that reached at the peak stress. When observed "post mortem" at microscopic scale, the dilatant structures are comprised of cataclastic deformation bands and cracks in some larger crystals.
International Journal of Rock Mechanics and Mining Science

hal-00767563
https://hal.archives-ouvertes.fr/hal-00767563
DOI : 10.1016/j.ijrmms.2012.07.020

Éditeur(s) : HAL CCSD Paris : Muséum national d'histoire naturelle
Résumé : International audience
The decline of meso-predators such as reef sharks is a concern as such species can have importantecological roles in maintaining reef ecosystem resilience. Two field trips conducted in August 2010 and November2011 to the Chesterfield archipelago (Coral Sea) allowed us to assess the abundances and average sizes ofmedium-bodied Carcharhinidae with a specific focus on grey reef shark (Carcharhinus amblyrhynchos), throughfishing (46 hours of accumulated effort) and underwater visual censuses (25 hours of accumulated effort). Wefound low abundance and small average total length (TL) for all reef shark species, and in the case of the greyreef shark, an average abundance of 2.1 individuals/dive with the majority of animals less than 110 cm TL. Wecompared our findings with historical data and, given our low sampling effort, we so far hypothesise that a generalstrong decline in the reef shark populations may have occurred in this area, probably due to recent overfishing.The enforcement of conservation measures is strongly recommended among these remote reefs as well ascomplementary studies for confirming this hypothesis.
Le déclin de méso-prédateurs tels que les requins de récif pose problème dans la mesure où ces espèces peuventavoir un rôle important dans le maintien de la résilience des écosystèmes coralliens. Deux missions conduitesen août 2010 et novembre 2011 dans l’archipel des Chesterfield (mer de Corail) nous ont permis d’évaluer lesabondances et longueurs totales (LT) moyennes de Carcharhinidae côtiers, en particulier du requin gris (Carcharhinusamblyrhynchos), à partir de sessions de pêche (46 heures au total) et de comptages sous-marins (25 heuresau total). Nous avons globalement trouvé de très faibles abondances et tailles moyennes avec, spécifiquementpour le requin gris, une abondance moyenne de 2,1 individus/plongée et une majorité d’animaux avec des LTinférieures à 110 cm. Nous avons comparé ces résultats à des données historiques et, étant donné certaines limitesde notre échantillonnage, nous nous cantonnons à poser l’hypothèse d’un déclin généralisé des populationsde requins de récifs dans cette zone, probablement dû à la surpêche. La mise en oeuvre effective de mesures deconservation est fortement recommandée au sein de ces récifs éloignés, de même que des études complémentairespour confirmer cette hypothèse.
ISSN: 0399-0974

hal-01281158
https://hal-univ-perp.archives-ouvertes.fr/hal-01281158

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Ciguatera Fish Poisoning (CFP) is a non-bacterial seafood poisoning well characterized in the remote archipelagos of French Polynesia, yet poorly documented in the Society archipelago, most notably on Moorea, the second most populated island in French Polynesia, which counts a high proportion of fishermen fishing on a regular basis. To address this knowledge gap, a holistic study of the ciguatera issue was conducted on Moorea. First, ciguatera risk was analysed in terms of incidence rate, fish species most commonly involved and risk stratification in Moorea lagoon based on 2007–2013 epidemiological data. A mean incidence rate of 8 cases per 10,000 inhabitants for the study period and an average under-reporting rate of 54% were found. Taking into account hospitalization and medication fees, and loss of productive days, the health-related costs due to CFP were estimated to be USD $1613 and $749 for each reported and unreported case, respectively, with an overall cost of USD $241,847 for the study period. Comparison of the present status of CFP on Moorea with a risk map established in the late 1970’s showed that the spatial distribution of the risk has stayed relatively stable in time, with the north shore of the island remaining the most prone to ciguatera. Evaluation of the current knowledge on CFP among different populations groups, i.e. fishermen, residents and visitors, was also conducted through direct and indirect interviews. About half of the fishermen interviewed were actually able to identify risky fishing areas. While, overall, the CFP risk perception in the fishing community of Moorea seemed accurate, although not scientifically complete, it was sufficient for the safe practice of their fishing activities. This may be due in part to adaptive responses adopted by 36% of the fishermen interviewed, such as the avoidance of either high-risk fishing sites or toxic species. At the residents and visitors’ level, the study points out a striking lack of awareness of the CFP issue among visitors, as compared to local residents. Indeed, less than 25% of Moorea visitors vs. an average of 98% in residents were aware of CFP or of its presence on the island. Interestingly, evaluation of the fish consumption preferences showed that 70% of visitors do not consume lagoon fish during their stay, not for fear of CFP, but mainly due to the lack of availability of these species in recreational facilities or because they have nutritional preference for pelagic fish. This lack of awareness, along with the report by several CFP patients of the consumption of fish species yet banned for sale, stress the need for improved communication efforts on this critical issue among both residents and visitors on Moorea. The implementation of a public outreach strategy is proposed, based on both existing information networks and low-cost communication actions through information displays at various strategic locations, e.g. Tahiti-Faa’a international airport, the ferry boat station, recreational facilities, as well as the major trading points on Moorea Island.
ISSN: 1568-9883

hal-01391648
https://hal-univ-perp.archives-ouvertes.fr/hal-01391648
DOI : 10.1016/j.hal.2016.10.003

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Marine Protected Areas (MPAs), if well designed and managed, can produce conservation benefits to fish assemblages within no-take zones and fishery benefits in neighboring areas through ‘spillover’. However, although plenty of studies have provided evidence of the benefits produced within MPA boundaries, overall benefits to local fisheries, especially via spillover, seem to be still unclear. Because of the lost fishing grounds following an MPA establishment, local fishermen usually oppose MPAs. There is, therefore, the urgent need for a better understanding of the mechanism(s) through which MPAs can export fishable fish biomass towards adjacent fished areas, a process that could counterbalance the loss of fishing grounds. Here we review the literature on spillover for refining the terminology, detailing the underlying mechanisms and identifying both the existing and needed methodological approaches to measure spillover. Operationally, two types of spillover should be considered: ecological spillover (i.e. the net export of juvenile, subadult and adult biomass from MPAs outwards driven by density-dependent processes) and the fishery spillover (i.e. the proportion of this biomass that can be fished, taking into account regulations and accessibility). Underwater visual census and tagging/tracking may allow getting evidence of ecological spillover, while experimental catch data are essential to assess and monitor fishery spillover, which is the main component of MPAs that can provide direct benefit to local fisheries.
ISSN: 1617-1381

hal-01325478
https://hal-univ-perp.archives-ouvertes.fr/hal-01325478
DOI : 10.1016/j.jnc.2016.04.004

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
ISSN: 1023-6244

hal-01310543
https://hal-univ-perp.archives-ouvertes.fr/hal-01310543
DOI : 10.1080/10236244.2016.1157929