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1. Challenging trophic position assessments in complex ecosystems: Calculation method, choice of baseline, trophic enrichment factors, season and feeding guild do matter: A case study from Marquesas Islands coral reefs

Author

Yves Letourneur, Pauline Fey, Jan Dierking, René Galzin, and Valeriano Parravicini

Subjects
assessment methods, consumers, food webs, primary producers, trophic position, Ecology, QH540-549.5
Abstract

Abstract Assessments of ecosystem functioning are a fundamental ecological challenge and an essential foundation for ecosystem‐based management. Species trophic position (TP) is essential to characterize food web architecture. However, despite the intuitive nature of the concept, empirically estimating TP is a challenging task due to the complexity of trophic interaction networks. Various methods are proposed to assess TPs, including using different sources of organic matter at the base of the food web (the ‘baseline’). However, it is often not clear which methodological approach and which baseline choices are the most reliable. Using an ecosystem‐wide assessment of a tropical reef (Marquesas Islands, with available data for 70 coral reef invertebrate and fish species), we tested whether different commonly used TP estimation methods yield similar results and, if not, whether it is possible to identify the most reliable method. We found significant differences in TP estimates of up to 1.7 TPs for the same species, depending on the method and the baseline used. When using bulk stable isotope data, the choice of the baseline significantly impacted TP values. Indeed, while nitrogen stable isotope (δ15N) values of macroalgae led to consistent TP estimates, those using phytoplankton generated unrealistically low TP estimates. The use of a conventional enrichment factor (i.e. 3.4‰) or a ‘variable’ enrichment factor (i.e. according to feeding guilds) also produced clear discrepancies between TP estimates. TPs obtained with δ15N values of source amino acids (compound‐specific isotope analysis) were close to those assessed with macroalgae. An opposite seasonal pattern was found, with significantly lower TPs in winter than in summer for most species, with particularly pronounced differences for lower TP species. We use the observed differences to discuss possible drivers of the diverging TP estimates and the potential ecological implications.

Published
2024
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2. C and N stable isotopes enlighten the trophic behaviour of the dugong (Dugong dugon)

Author

Martin Thibault, Yves Letourneur, Christophe Cleguer, Claire Bonneville, Marine J. Briand, Solène Derville, Paco Bustamante, and Claire Garrigue

Subjects
Medicine, Science
Abstract

Abstract The dugong (Dugong dugon), a large marine mammal herbivore of the Indo-Pacific, is vulnerable to extinction at a global scale due to a combination of human-related threats including habitat degradation. The species forages on seagrass habitats (marine phanerogams) and plays a key role in the functioning and sensitivity of these declining coastal ecosystems. The trophic behaviour and plasticity of dugong populations in response to extrinsic and intrinsic factors are therefore crucial features to both dugong and seagrass conservation. Yet, this knowledge remains limited to few visual observations and analyses of mouth, stomach or faecal contents of stranded individuals. We take advantage of a long-term monitoring of stranded individuals from the endangered New Caledonian population to depict features of dugongs’ trophic ecology from Carbon and Nitrogen stable isotopes. A total of 59 dugong skin samples were used to portrait the stable isotope niche of dugongs according to their sex and maturity. In light of previous work conducted in New Caledonia, a subset of these samples was used to model the trophic mix of dugong males and females. Our stable isotope mixing models used C and N isotope values of 10 taxa bbelonging to five divisions of metazoans, plants, and chromists. Our results represent the first estimate of the species dietary niche in the isotopic space. They suggest that the diet of dugong calves overlaps more with that of adult females (δ13C: − 6.38 ± 1.13 ‰; δ15N: 2.49 ± 1.10 ‰) than males (δ13C: − 5.92 ± 1.10 ‰; δ15N: 3.69 ± 1.28 ‰). Further, we highlight differences in the expected trophic mix of dugong adult males and females. From these, we formulate a sex-specific foraging behaviour hypothesis in dugongs, whereby lactating females could forage over smaller spatial ranges but more diverse food sources thanmales. The study emphasizes the importance of long-term stranding monitoring programs to study the ecology of marine mammals.. Finally, it depicts an ecological feature that may contribute to the sensitivity of vulnerable dugongs to ongoing changes on tropical coastal ecosystems.

Published
2024
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3. Multi-trophic markers illuminate the understanding of the functioning of a remote, low coral cover Marquesan coral reef food web

Author

Pauline Fey, Valeriano Parravicini, Daniela Bănaru, Jan Dierking, René Galzin, Benoit Lebreton, Tarik Meziane, Nicholas V. C. Polunin, Mayalen Zubia, and Yves Letourneur

Subjects
Medicine, Science
Abstract

Abstract We studied the food web structure and functioning of a coral reef ecosystem in the Marquesas Islands, French Polynesia, characterized by low coral cover, high sea surface temperature and meso- to eutrophic waters. The Marquesas constitute a relevant ecosystem to understand the functioning of low diversity reefs that are also subject to global change. A multi-tracer assessment of organic matter pathways was run to delineate ecosystem functioning, using analysis of fatty acids, bulk and compound specific stable isotope analysis and stable isotopes mixing models. Macroalgae and phytoplankton were the two major food sources fueling this food web with, however, some marked seasonal variations. Specifically, zooplankton relied on phytoplankton-derived organic matter and herbivorous fishes on macroalgae-derived organic matter to a much higher extent in summer than in winter (~ 75% vs. ~ 15%, and ~ 70 to 75% vs. ~ 5 to 15%, respectively) . Despite remarkably high δ15N values for all trophic compartments, likely due to local dynamics in the nitrogen stock, trophic levels of consumers were similar to those of other coral reef ecosystems. These findings shed light on the functioning of low coral cover systems, which are expected to expand worldwide under global change.

Published
2021
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4. Isotopic discrimination in helminths infecting coral reef fishes depends on parasite group, habitat within host, and host stable isotope value

Author

Philip M. Riekenberg, Marine J. Briand, Thibaud Moléana, Pierre Sasal, Marcel T. J. van der Meer, David W. Thieltges, and Yves Letourneur

Subjects
Medicine, Science
Abstract

Abstract Stable isotopes of carbon and nitrogen characterize trophic relationships in predator–prey relationships, with clear differences between consumer and diet (discrimination factor Δ13C and Δ15N). However, parasite–host isotopic relationships remain unclear, with Δ13C and Δ15N remaining incompletely characterized, especially for helminths. In this study, we used stable isotopes to determine discrimination factors for 13 parasite–host pairings of helminths in coral reef fish. Differences in Δ15N values grouped according to parasite groups and habitat within the host with positive Δ15N values observed for trematodes and nematodes from the digestive tract and variable Δ15N values observed for cestodes and nematodes from the general cavity. Furthermore, Δ13C values showed more complex patterns with no effect of parasite group or habitat within host. A negative relationship was observed between Δ15N and host δ15N values among different host-parasite pairings as well as within 7 out of the 13 pairings, indicating that host metabolic processing affects host-parasite discrimination values. In contrast, no relationships were observed for Δ13C values. Our results indicate that parasite group, habitat within host, and host stable isotope value drive Δ15N of helminths in coral reef fish while their effect on Δ13C is more idiosyncratic. These results call for use of taxon- or species-specific and scaled framework for bulk stable isotopes in the trophic ecology of parasites.

Published
2021
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5. The α-minimum convex polygon as a relevant tool for isotopic niche statistics

Author

Pauline Fey, Yves Letourneur, and Silvère Bonnabel

Subjects
Minimum convex polygon, Non-parametric statistics, Niche overlap, Stable isotope analysis, Trophic niche, Ecology, QH540-549.5
Abstract

Ecological (isotopic) niche refers to a surface in a two-dimensional space, where the axes correspond to environmental variables that reflect values of stable isotopes incorporated in an animal's tissues. Carbon and nitrogen stable isotope ratios (δ13C-δ15N) notably provide precious information about trophic ecology, resource and habitat use, and population dynamics. Various metrics allow for isotopic niche size and overlap assessment. In this paper, we advocate α-minimum convex polygons (MCP) - that have long been used for home range estimation – as a relevant tool for isotopic niche size, overlap, and characteristics. The method allows for outlier rejection while being suited to data that are not Gaussian in the bivariate isotopic (δ13C-δ15N) space. The proposed indicators are compared to other existing approaches and are shown to be complementary. Notably an indicator of divergence within the niche is introduced, and allows for comparisons at low (n > 6) and different sample sizes. The R code is made publicly available and will enable ecologists to perform isotopic niche comparison, contraction and expansion assessment, and overlap, based on various methods.

Published
2021
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7. Preliminary indication of ontogenetic and spatial variations in the whole otolith isotopic and elemental signatures of Solea solea in the Gulf of Lions (NW Mediterranean)

Author

Fabien Morat, Raymonde Lecomte-Finiger, Dominique Blamart, Michel Robert, and Yves Letourneur

Subjects
flatfish, otolith microchemistry, stable isotope, coastal lagoon, river rhône, Aquaculture. Fisheries. Angling, SH1-691
Abstract

Knowledge of fish life cycles is important for exploited species. In the Mediterranean Sea, catches of common sole (Solea solea) have fluctuated widely since the 1970s. Solea solea displays an ontogenetic shift in habitat: sole larvae are marine, juveniles inhabit shallow marine waters and coastal lagoons and adults inhabit deeper marine waters. Although the results of this study were obtained using only a small set of individuals, the otolith elemental composition and isotopic ratios were investigated for the three life stages (post-larval, juvenile and adult) in order to acquire a better knowledge of the variability in environmental conditions experienced by the common sole at each life stage in the NW Mediterranean. Moreover, this study provides the first evaluation of the potential of whole otolith microchemistry for investigating habitat connectivity in sole populations from the Gulf of Lions. The elemental and isotopic signatures of otoliths of post-larvae captured in various environments appear to show variations related to the River Rhône inputs (high Ba/Ca and low Sr/Ca ratios). Juveniles appear to show significant variations in otolith elemental and isotopic compositions depending not only on the physico-chemical properties of water in the nurseries they inhabit (Rhône River, Thau or Mauguio lagoons), but also as a result of variations in the chemical composition of their surrounding sediments and in their benthic prey. Adults exhibit otolith differences for isotopic ratios only, which is probably linked to the River Rhône inputs. Finally, several significant relationships were observed between otolith elemental composition and fish size in specimens captured at the River Rhône mouth. However, these variations seem to be an indication of the composition acquired in each environment rather than a sign of ontogeny.

Published
2012
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8. The great melting pot. Common sole population connectivity assessed by otolith and water fingerprints.

Author

Fabien Morat, Yves Letourneur, Jan Dierking, Christophe Pécheyran, Gilles Bareille, Dominique Blamart, and Mireille Harmelin-Vivien

Subjects
Medicine, Science
Abstract

Quantifying the scale and importance of individual dispersion between populations and life stages is a key challenge in marine ecology. The common sole (Solea solea), an important commercial flatfish in the North Sea, Atlantic Ocean and the Mediterranean Sea, has a marine pelagic larval stage, a benthic juvenile stage in coastal nurseries (lagoons, estuaries or shallow marine areas) and a benthic adult stage in deeper marine waters on the continental shelf. To date, the ecological connectivity among these life stages has been little assessed in the Mediterranean. Here, such an assessment is provided for the first time for the Gulf of Lions, NW Mediterranean, based on a dataset on otolith microchemistry and stable isotopic composition as indicators of the water masses inhabited by individual fish. Specifically, otolith Ba/Ca and Sr/Ca profiles, and δ(13)C and δ(18)O values of adults collected in four areas of the Gulf of Lions were compared with those of young-of-the-year collected in different coastal nurseries. Results showed that a high proportion of adults (>46%) were influenced by river inputs during their larval stage. Furthermore Sr/Ca ratios and the otolith length at one year of age revealed that most adults (∼70%) spent their juvenile stage in nurseries with high salinity, whereas the remainder used brackish environments. In total, data were consistent with the use of six nursery types, three with high salinity (marine areas and two types of highly saline lagoons) and three brackish (coastal areas near river mouths, and two types of brackish environments), all of which contributed to the replenishment of adult populations. These finding implicated panmixia in sole population in the Gulf of Lions and claimed for a habitat integrated management of fisheries.

Published
2014
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9. Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes.

Author

Camilo Mora, Octavio Aburto-Oropeza, Arturo Ayala Bocos, Paula M Ayotte, Stuart Banks, Andrew G Bauman, Maria Beger, Sandra Bessudo, David J Booth, Eran Brokovich, Andrew Brooks, Pascale Chabanet, Joshua E Cinner, Jorge Cortés, Juan J Cruz-Motta, Amilcar Cupul Magaña, Edward E Demartini, Graham J Edgar, David A Feary, Sebastian C A Ferse, Alan M Friedlander, Kevin J Gaston, Charlotte Gough, Nicholas A J Graham, Alison Green, Hector Guzman, Marah Hardt, Michel Kulbicki, Yves Letourneur, Andres López Pérez, Michel Loreau, Yossi Loya, Camilo Martinez, Ismael Mascareñas-Osorio, Tau Morove, Marc-Olivier Nadon, Yohei Nakamura, Gustavo Paredes, Nicholas V C Polunin, Morgan S Pratchett, Héctor Reyes Bonilla, Fernando Rivera, Enric Sala, Stuart A Sandin, German Soler, Rick Stuart-Smith, Emmanuel Tessier, Derek P Tittensor, Mark Tupper, Paolo Usseglio, Laurent Vigliola, Laurent Wantiez, Ivor Williams, Shaun K Wilson, and Fernando A Zapata

Subjects
Biology (General), QH301-705.5
Abstract

Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas.

Published
2011
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10. Climate warming, marine protected areas and the ocean-scale integrity of coral reef ecosystems.

Author

Nicholas A J Graham, Tim R McClanahan, M Aaron MacNeil, Shaun K Wilson, Nicholas V C Polunin, Simon Jennings, Pascale Chabanet, Susan Clark, Mark D Spalding, Yves Letourneur, Lionel Bigot, René Galzin, Marcus C Ohman, Kajsa C Garpe, Alasdair J Edwards, and Charles R C Sheppard

Subjects
Medicine, Science
Abstract

Coral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. While the contribution of a warming climate to the loss of live coral cover has been well documented across large spatial and temporal scales, the associated effects on fish have not. Here, we respond to recent and repeated calls to assess the importance of local management in conserving coral reefs in the context of global climate change. Such information is important, as coral reef fish assemblages are the most species dense vertebrate communities on earth, contributing critical ecosystem functions and providing crucial ecosystem services to human societies in tropical countries. Our assessment of the impacts of the 1998 mass bleaching event on coral cover, reef structural complexity, and reef associated fishes spans 7 countries, 66 sites and 26 degrees of latitude in the Indian Ocean. Using Bayesian meta-analysis we show that changes in the size structure, diversity and trophic composition of the reef fish community have followed coral declines. Although the ocean scale integrity of these coral reef ecosystems has been lost, it is positive to see the effects are spatially variable at multiple scales, with impacts and vulnerability affected by geography but not management regime. Existing no-take marine protected areas still support high biomass of fish, however they had no positive affect on the ecosystem response to large-scale disturbance. This suggests a need for future conservation and management efforts to identify and protect regional refugia, which should be integrated into existing management frameworks and combined with policies to improve system-wide resilience to climate variation and change.

Published
2008
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13. Biological trade-offs underpin coral reef ecosystem functioning

Author

Nina M. D. Schiettekatte, Simon J. Brandl, Jordan M. Casey, Nicholas A. J. Graham, Diego R. Barneche, Deron E. Burkepile, Jacob E. Allgeier, Jesús E. Arias-Gonzaléz, Graham J. Edgar, Carlos E. L. Ferreira, Sergio R. Floeter, Alan M. Friedlander, Alison L. Green, Michel Kulbicki, Yves Letourneur, Osmar J. Luiz, Alexandre Mercière, Fabien Morat, Katrina S. Munsterman, Enrico L. Rezende, Fabian A. Rodríguez‐Zaragoza, Rick D. Stuart-Smith, Laurent Vigliola, Sébastien Villéger, Valeriano Parravicini, Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Queen's University [Kingston, Canada], Australian Institute of Marine Science (AIMS), Marine Science Institute [Santa Barbara] (MSI), University of California [Santa Barbara] (UC Santa Barbara), University of California (UC)-University of California (UC), University of Michigan [Ann Arbor], University of Michigan System, University of Tasmania [Hobart, Australia] (UTAS), Universidade Federal Fluminense [Rio de Janeiro] (UFF), Universidade Federal de Santa Catarina = Federal University of Santa Catarina [Florianópolis] (UFSC), University of Hawaii, King Abdullah University of Science and Technology (KAUST), Institut de Recherche pour le Développement (IRD [France-Ouest]), Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), Charles Darwin University [Australia], Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Ecology, Evolution and Marine Biology [Santa Barbara] (EEMB), Pontificia Universidad Católica de Chile (UC), Universidad de Guadalajara, MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), and ANR-17-CE32-0006,REEFLUX,Flux d'énergie au sein des récifs coralliens: une perspective basée sur les vertébrés(2017)

Subjects
[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Ecology, Coral Reefs, Climate Change, Animals, Biodiversity, Biomass, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Ecosystem, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

International audience; Human impact increasingly alters global ecosystems, often reducing biodiversity and disrupting the provision of essential ecosystem services to humanity. Therefore, preserving ecosystem functioning is a critical challenge of the twenty-first century. Coral reefs are declining worldwide due to the pervasive effects of climate change and intensive fishing, and although research on coral reef ecosystem functioning has gained momentum, most studies rely on simplified proxies, such as fish biomass. This lack of quantitative assessments of multiple process-based ecosystem functions hinders local and regional conservation efforts. Here we combine global coral reef fish community surveys and bioenergetic models to quantify five key ecosystem functions mediated by coral reef fishes. We show that functions exhibit critical trade-offs driven by varying community structures, such that no community can maximize all functions. Furthermore, functions are locally dominated by few species, but the identity of dominant species substantially varies at the global scale. In fact, half of the 1,110 species in our dataset are functionally dominant in at least one location. Our results reinforce the need for a nuanced, locally tailored approach to coral reef conservation that considers multiple ecological functions beyond the effect of standing stock biomass.

Published
2022

14. Tracing trophic pathways through the marine ecosystem of Rapa Nui (Easter Island)

Author

Chris Harrod, Naiti A. Morales, Paula Plaza, Yves Letourneur, Erika Meerhoff, Iván A. Hinojosa, Germán Zapata-Hernández, Javier Sellanes, Sergio A. Carrasco, Carlos F. Gaymer, and Beatriz Yannicelli

Subjects
geography, geography.geographical_feature_category, Ecology, Environmental science, Marine ecosystem, Coral reef, Aquatic Science, Tracing, Food web, Nature and Landscape Conservation, Trophic level
Published
2021

18. Vertiges

Author

Yves Letourneur and Yves Letourneur

Published
2012

19. Multi-trophic markers illuminate the understanding of the functioning of a remote, low coral cover Marquesan coral reef food web

Author

Nicholas Polunin, Pauline Fey, Jan Dierking, Daniela Bănaru, Yves Letourneur, Mayalen Zubia, Tarik Meziane, Valeriano Parravicini, Benoit Lebreton, R. Galzin, Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), School of Natural and Environmental Sciences ( Newcastle University), Ecosystèmes Insulaires Océaniens (UMR 241) (EIO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), Institut de Recherche pour le Développement (IRD), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Université de la Nouvelle-Calédonie (UNC), CRIOBE, PSL Research University, USR 3278 EPHE-CNRS-UPVD, LabEx « Corail », Université de Perpignan, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and UMR EIO (UPF-IRD-ILM-IFREMER), Université de La Polynésie Française

Subjects
0106 biological sciences, Science, 010603 evolutionary biology, 01 natural sciences, Zooplankton, Article, Phytoplankton, Ecosystem, 14. Life underwater, Reef, Isotope analysis, Trophic level, geography, Multidisciplinary, geography.geographical_feature_category, Ecology, 010604 marine biology & hydrobiology, Coral reef, 15. Life on land, Food web, Ocean sciences, [SDU]Sciences of the Universe [physics], Environmental science, Medicine, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

We studied the food web structure and functioning of a coral reef ecosystem in the Marquesas Islands, French Polynesia, characterized by low coral cover, high sea surface temperature and meso- to eutrophic waters. The Marquesas constitute a relevant ecosystem to understand the functioning of low diversity reefs that are also subject to global change. A multi-tracer assessment of organic matter pathways was run to delineate ecosystem functioning, using analysis of fatty acids, bulk and compound specific stable isotope analysis and stable isotopes mixing models. Macroalgae and phytoplankton were the two major food sources fueling this food web with, however, some marked seasonal variations. Specifically, zooplankton relied on phytoplankton-derived organic matter and herbivorous fishes on macroalgae-derived organic matter to a much higher extent in summer than in winter (~ 75% vs. ~ 15%, and ~ 70 to 75% vs. ~ 5 to 15%, respectively) . Despite remarkably high δ15N values for all trophic compartments, likely due to local dynamics in the nitrogen stock, trophic levels of consumers were similar to those of other coral reef ecosystems. These findings shed light on the functioning of low coral cover systems, which are expected to expand worldwide under global change.

Published
2021

20. Phylogeny, body morphology, and trophic level shape intestinal traits in coral reef fishes

Author

Mattia Ghilardi, Jordan M. Casey, Nina M. D. Schiettekatte, Yves Letourneur, Samuel Degregori, Alexandre Mercière, Sonia Bejarano, Simon J. Brandl, Fabien Morat, Valeriano Parravicini, Leibniz Centre for Tropical Marine Research (ZMT), Universität Bremen, Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre de Synthèse et d’Analyse sur la Biodiversité (CESAB), Fondation pour la recherche sur la Biodiversité (FRB), Department of Ecology & Evolutionary Biology, University of California [Los Angeles] (UCLA), University of California-University of California, Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Université de la Nouvelle-Calédonie (UNC), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Université de Perpignan Via Domitia (UPVD)-École Pratique des Hautes Études (EPHE), University of California (UC)-University of California (UC), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), and ANR-17-CE32-0006,REEFLUX,Flux d'énergie au sein des récifs coralliens: une perspective basée sur les vertébrés(2017)

Subjects
0106 biological sciences, Zoology, Morphology (biology), Biology, 010603 evolutionary biology, 01 natural sciences, 03 medical and health sciences, evolutionary conservatism, Phylogenetics, Convergent evolution, [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology, 14. Life underwater, convergent evolution, QH540-549.5, Ecology, Evolution, Behavior and Systematics, Original Research, 030304 developmental biology, Nature and Landscape Conservation, Trophic level, digestive traits, 0303 health sciences, geography, geography.geographical_feature_category, Ecology, Phylogenetic tree, Bayesian phylogenetic comparative method, gut length, Coral reef, Interspecific competition, Trait, fish diet, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

Trait‐based approaches are increasingly used to study species assemblages and understand ecosystem functioning. The strength of these approaches lies in the appropriate choice of functional traits that relate to the functions of interest. However, trait–function relationships are often supported by weak empirical evidence.Processes related to digestion and nutrient assimilation are particularly challenging to integrate into trait‐based approaches. In fishes, intestinal length is commonly used to describe these functions. Although there is broad consensus concerning the relationship between fish intestinal length and diet, evolutionary and environmental forces have shaped a diversity of intestinal morphologies that is not captured by length alone.Focusing on coral reef fishes, we investigate how evolutionary history and ecology shape intestinal morphology. Using a large dataset encompassing 142 species across 31 families collected in French Polynesia, we test how phylogeny, body morphology, and diet relate to three intestinal morphological traits: intestinal length, diameter, and surface area.We demonstrate that phylogeny, body morphology, and trophic level explain most of the interspecific variability in fish intestinal morphology. Despite the high degree of phylogenetic conservatism, taxonomically unrelated herbivorous fishes exhibit similar intestinal morphology due to adaptive convergent evolution. Furthermore, we show that stomachless, durophagous species have the widest intestines to compensate for the lack of a stomach and allow passage of relatively large undigested food particles.Rather than traditionally applied metrics of intestinal length, intestinal surface area may be the most appropriate trait to characterize intestinal morphology in functional studies., Intestinal morphology is key to integrating digestive and assimilative processes into trait‐based approaches. Yet intestinal length alone has been commonly use for this purpose in fishes. Our study demonstrates that evolution and ecology have shaped a great diversity of intestinal morphologies in coral reef fishes that cannot be captured by length alone. We show that intestinal traits are clear indicators of fish trophic roles and intestinal surface area may be a most suitable trait to apply in functional studies than intestinal length.

Published
2021

21. Diel changes in structure and trophic functions of motile benthic invertebrates on coral reefs at Rapa Nui (Easter Island)

Author

Rodrigo S. Rios, Germán Zapata-Hernández, Iván A. Hinojosa, Javier Sellanes, and Yves Letourneur

Subjects
Biomass (ecology), geography, geography.geographical_feature_category, Ecology, fungi, Detritivore, Biodiversity, Coral reef, Aquatic Science, Biology, Benthic zone, Diel vertical migration, Reef, Ecology, Evolution, Behavior and Systematics, Trophic level
Abstract

Coral reefs are structurally complex habitats that provide diverse shelter for motile benthic invertebrates (MBI), including those with cryptic and nocturnal behaviors. In this study, diel changes in MBI structure (species composition, density, and biomass) and functions (trophic groups and isotopic diversity indices) were examined on coral reefs at Rapa Nui (27° S, 109° W). Diurnal and nocturnal surveys (March 2016) revealed that echinoderms were the dominant invertebrates throughout the diel cycle in terms of density, biomass, and their trophic role. The density and biomass of MBI were higher at night than during the day. Significant diel changes were detected in the structure of MBI and trophic groups, where the diurnal assemblages were mostly herbivores and the nocturnal assemblages were mostly detritivores. Moreover, the isotopic uniqueness index indicated that nocturnal MBI were trophically more redundant than their diurnal counterparts; consequently, the high nocturnal biodiversity did not necessarily increase trophic diversity. This time and trophic partitioning of MBI could have important consequences for energy transfer on the reefs and must be considered in future monitoring programs. Endemic taxa represented approximately a quarter of the species (26%), but had low density and biomass during both time periods, suggesting a modest influence on energy transfers on these coral reefs. However, their restricted geographic distribution and current low abundances could make these species vulnerable to extinction; therefore, management and conservation actions in the new multiple-use marine protected area of Rapa Nui should include these species.

Published
2021

22. The Bouraké semi-enclosed lagoon (New Caledonia). A natural laboratory to study the life-long adaptation of a coral reef ecosystem to climate change-like conditions

Author

Federica Maggioni, Claude Payri, Carlo Cerrano, Yves Letourneur, Barbara Calcinai, Mireille Pujo-Pay, Riccardo Rodolfo-Metalpa, Jérome Aucan, and Francesca Benzoni

Subjects
geography, geography.geographical_feature_category, Benthic zone, Ecology, Environmental science, Climate change, Seawater, Ecosystem, Estuary, Coral reef, Mangrove, Reef
Abstract

According to current experimental evidence, coral reefs could disappear within the century if CO2 emissions remain unabated. However, recent discoveries of diverse and high cover reefs that already thrive under extreme conditions seem to contradict these projections. Volcanic CO2 vents, semi-enclosed lagoons and mangrove estuaries are unique study sites where one or more ecologically relevant parameters for life in the oceans are close or even worse than currently projected for the year 2100. These natural analogues of future conditions hold new hope for the future of coral reefs and provide unique natural laboratories to explore how reef species could keep pace with climate change. To achieve this, it is essential to characterize their environment as a whole, and accurately consider all possible environmental factors that may differ from what is expected in the future and that may possibly alter the ecosystem response. In this study, we focus on the semi-enclosed lagoon of Bouraké (New Caledonia, SW Pacific Ocean) where a healthy reef ecosystem thrives in warm, acidified and deoxygenated water. We used a multi-scale approach to characterize the main physical-chemical parameters and mapped the benthic community composition (i.e., corals, sponges, and macroalgae). The data revealed that most physical and chemical parameters are regulated by the tide, strongly fluctuate 3 to 4 times a day, and are entirely predictable. The seawater pH and dissolved oxygen decrease during falling tide and reach extreme low values at low tide (7.2 pHT and 1.9 mg O2 L−1 at Bouraké, vs 7.9 pHT and 5.5 mg O2 L−1 at reference reefs). Dissolved oxygen, temperature, and pH fluctuates according to the tide of up to 4.91 mg O2 L−1, 6.50 °C, and 0.69 pHT units on a single day. Furthermore, the concentration of most of the chemical parameters was one- to 5-times higher at the Bouraké lagoon, particularly for organic and inorganic carbon and nitrogen, but also for some nutrients, notably silicates. Surprisingly, despite extreme environmental conditions and altered seawater chemical composition, our results reveal a diverse and high cover community of macroalgae, sponges and corals accounting for 28, 11 and 66 species, respectively. Both environmental variability and nutrient imbalance might contribute to their survival under such extreme environmental conditions. We describe the natural dynamics of the Bouraké ecosystem and its relevance as a natural laboratory to investigate the benthic organism’s adaptive responses to multiple stressors like future climate change conditions.

Published
2021

24. Isotopic discrimination in helminths infecting coral reef fishes depends on parasite group, habitat within host, and host stable isotope value

Author

David W. Thieltges, Marcel T J van der Meer, Pierre Sasal, Philip M. Riekenberg, Yves Letourneur, Marine J. Briand, Thibaud Moléana, Royal Netherlands Institute for Sea Research (NIOZ), Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Excellence CORAIL (LabEX CORAIL), Institut de Recherche pour le Développement (IRD)-Université des Antilles et de la Guyane (UAG)-École des hautes études en sciences sociales (EHESS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de La Réunion (UR)-Université de la Polynésie Française (UPF)-Université de la Nouvelle-Calédonie (UNC)-Institut d'écologie et environnement-Université des Antilles (UA), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Université de la Nouvelle-Calédonie (UNC), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), Université des Antilles (UA)-Institut d'écologie et environnement-Université de la Nouvelle-Calédonie (UNC)-Université de la Polynésie Française (UPF)-Université de La Réunion (UR)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École des hautes études en sciences sociales (EHESS)-Université des Antilles et de la Guyane (UAG)-Institut de Recherche pour le Développement (IRD)

Subjects
0106 biological sciences, Stable isotope analysis, Coral reef fish, Science, Ecosystem ecology, [SDV]Life Sciences [q-bio], Zoology, Biology, 010603 evolutionary biology, 01 natural sciences, Article, Host-Parasite Interactions, Isotopes, Helminths, [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology, Animals, [SDV.MP.PAR]Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, 14. Life underwater, Ecosystem, Trophic level, geography, Multidisciplinary, geography.geographical_feature_category, δ13C, Coral Reefs, Stable isotope ratio, Host (biology), 010604 marine biology & hydrobiology, Fishes, δ15N, Coral reef, Medicine, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract

Stable isotopes of carbon and nitrogen characterize trophic relationships in predator–prey relationships, with clear differences between consumer and diet (discrimination factor Δ13C and Δ15N). However, parasite–host isotopic relationships remain unclear, with Δ13C and Δ15N remaining incompletely characterized, especially for helminths. In this study, we used stable isotopes to determine discrimination factors for 13 parasite–host pairings of helminths in coral reef fish. Differences in Δ15N values grouped according to parasite groups and habitat within the host with positive Δ15N values observed for trematodes and nematodes from the digestive tract and variable Δ15N values observed for cestodes and nematodes from the general cavity. Furthermore, Δ13C values showed more complex patterns with no effect of parasite group or habitat within host. A negative relationship was observed between Δ15N and host δ15N values among different host-parasite pairings as well as within 7 out of the 13 pairings, indicating that host metabolic processing affects host-parasite discrimination values. In contrast, no relationships were observed for Δ13C values. Our results indicate that parasite group, habitat within host, and host stable isotope value drive Δ15N of helminths in coral reef fish while their effect on Δ13C is more idiosyncratic. These results call for use of taxon- or species-specific and scaled framework for bulk stable isotopes in the trophic ecology of parasites.

Published
2021

25. Author Correction: Multi-trophic markers illuminate the understanding of the functioning of a remote, low coral cover Marquesan coral reef food web

Author

Nicholas Polunin, Daniela Bănaru, Valeriano Parravicini, Mayalen Zubia, R. Galzin, Pauline Fey, Yves Letourneur, Jan Dierking, Benoit Lebreton, Tarik Meziane, Université de Perpignan Via Domitia (UPVD), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), and Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)

Subjects
Food Chain, Hot Temperature, Science, Polynesia, Zooplankton, Animals, Herbivory, Author Correction, Ecosystem, ComputingMilieux_MISCELLANEOUS, Trophic level, geography, Multidisciplinary, geography.geographical_feature_category, Coral Reefs, Ecology, Fatty Acids, Fishes, Coral reef, Seaweed, Food web, [SDU]Sciences of the Universe [physics], Isotope Labeling, Coral cover, Phytoplankton, Medicine
Abstract

We studied the food web structure and functioning of a coral reef ecosystem in the Marquesas Islands, French Polynesia, characterized by low coral cover, high sea surface temperature and meso- to eutrophic waters. The Marquesas constitute a relevant ecosystem to understand the functioning of low diversity reefs that are also subject to global change. A multi-tracer assessment of organic matter pathways was run to delineate ecosystem functioning, using analysis of fatty acids, bulk and compound specific stable isotope analysis and stable isotopes mixing models. Macroalgae and phytoplankton were the two major food sources fueling this food web with, however, some marked seasonal variations. Specifically, zooplankton relied on phytoplankton-derived organic matter and herbivorous fishes on macroalgae-derived organic matter to a much higher extent in summer than in winter (~ 75% vs. ~ 15%, and ~ 70 to 75% vs. ~ 5 to 15%, respectively) . Despite remarkably high δ

Published
2021

26. Individual back-calculated size-at-age based on otoliths from Pacific coral reef fish species

Author

Jason Vii, Samuel Degregori, Jordan M. Casey, René Galzin, Yves Letourneur, Simon J. Brandl, Alexandre Mercière, Fabien Morat, Pauline Fey, Jérémy Carlot, Jérémy Wicquart, Guillemette de Sinéty, Pierre Sasal, Jean Bienvenu, Nina M. D. Schiettekatte, Valeriano Parravicini, Laboratoire d'Excellence CORAIL (LabEX CORAIL), Université des Antilles (UA)-Institut d'écologie et environnement-Université de la Nouvelle-Calédonie (UNC)-Université de la Polynésie Française (UPF)-Université de La Réunion (UR)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École des hautes études en sciences sociales (EHESS)-Université des Antilles et de la Guyane (UAG)-Institut de Recherche pour le Développement (IRD), Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut de sciences exactes et appliquées (ISEA), and Université de la Nouvelle-Calédonie (UNC)

Subjects
0106 biological sciences, Statistics and Probability, Data Descriptor, Population dynamics, Coral reef fish, [SDV]Life Sciences [q-bio], Population, Library and Information Sciences, Biology, 010603 evolutionary biology, 01 natural sciences, Polynesia, Education, Otolithic Membrane, medicine, Temperate climate, Animals, Body Size, 14. Life underwater, Biomass, lcsh:Science, education, ComputingMilieux_MISCELLANEOUS, Otolith, Biomass (ecology), geography, education.field_of_study, geography.geographical_feature_category, Community level, Coral Reefs, 010604 marine biology & hydrobiology, Fishes, Coral reef, Computer Science Applications, Fishery, Ageing, medicine.anatomical_structure, [SDE]Environmental Sciences, Trait, lcsh:Q, Statistics, Probability and Uncertainty, Ichthyology, Information Systems
Abstract

Somatic growth is a critical biological trait for organismal, population, and ecosystem-level processes. Due to its direct link with energetic demands, growth also represents an important parameter to estimate energy and nutrient fluxes. For marine fishes, growth rate information is most frequently derived from sagittal otoliths, and most of the available data stems from studies on temperate species that are targeted by commercial fisheries. Although the analysis of otoliths is a powerful tool to estimate individual growth, the time-consuming nature of otolith processing is one barrier for collection of comprehensive datasets across multiple species. This is especially true for coral reef fishes, which are extremely diverse. Here, we provide back-calculated size-at-age estimates (including measures of uncertainty) based on sagittal otoliths from 710 individuals belonging to 45 coral reef fish species from French Polynesia. In addition, we provide Von Bertalanffy growth parameters which are useful to predict community level biomass production., Measurement(s) growth Technology Type(s) otolithometry Sample Characteristic - Organism Actinopterygii Sample Characteristic - Environment coral reef Sample Characteristic - Location French Polynesia Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.13027817

Published
2020

27. Impacts of host phylogeny, feeding styles, and parasite attachment site on isotopic discrimination in helminths infecting coral reef fish hosts

Author

Marcel T J van der Meer, Philip M. Riekenberg, Thibaud Moléana, Marine J. Briand, David W. Thieltges, Yves Letourneur, Pierre Sasal, Laboratoire d'Excellence CORAIL (LabEX CORAIL), Université des Antilles (UA)-Institut d'écologie et environnement-Université de la Nouvelle-Calédonie (UNC)-Université de la Polynésie Française (UPF)-Université de La Réunion (UR)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École des hautes études en sciences sociales (EHESS)-Université des Antilles et de la Guyane (UAG)-Institut de Recherche pour le Développement (IRD), Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Host (biology), Coral reef fish, Stable isotope ratio, 010604 marine biology & hydrobiology, [SDV]Life Sciences [q-bio], Zoology, Biology, 010603 evolutionary biology, 01 natural sciences, Taxon, Phylogenetics, Isotopes of carbon, [SDE]Environmental Sciences, Helminths, 14. Life underwater, Trophic level
Abstract

Stable isotopes of carbon and nitrogen characterize trophic relationships in predator-prey relationships, with clear differences between consumer and diet (discrimination factor, Δ13C, Δ15N). However, parasite-host isotopic relationships remain unclear, with Δ13C and Δ15N remaining incompletely characterized, especially for helminths. In this study, we used stable isotopes to determine discrimination factors for 13 parasite-host pairings of helminths in coral reef fish. Δ15N differences grouped according to phylogeny and attachment site on the hosts: Δ15N was positive for trematodes and nematodes from the digestive tract and varied for cestodes and nematodes from the general cavity. Δ13C showed more complex patterns with no effect of phylogeny or attachment site. A negative relationship was observed between Δ15N and host δ15N value among different host-parasite pairings as well as within 7 out of the 13 parings, indicating that host metabolic processing affects host-parasite discrimination values. In contrast, no relationships were observed for Δ13C. Our results indicate that host phylogeny, attachment site and host stable isotope value drive Δ15N of helminths in coral reef fish while Δ13C is more idiosyncratic. These results call for use of taxon- or species-specific and scaled framework for bulk stable isotopes in the trophic ecology of parasites.

Published
2020

28. Sources of organic matter in an atypical phytoplankton rich coral ecosystem, Marquesas Islands: composition and properties

Author

R. Galzin, Yves Letourneur, Mayalen Zubia, Pauline Fey, D. Bӑnaru, Tarik Meziane, Benoit Lebreton, Valeriano Parravicini, IRD NEW CALEDONIA NOUMEA NCL, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Laboratoire d'Excellence CORAIL (LabEX CORAIL), Université des Antilles (UA)-Institut d'écologie et environnement-Université de la Nouvelle-Calédonie (UNC)-Université de la Polynésie Française (UPF)-Université de La Réunion (UR)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École des hautes études en sciences sociales (EHESS)-Université des Antilles et de la Guyane (UAG)-Institut de Recherche pour le Développement (IRD), Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Université de la Nouvelle-Calédonie (UNC), Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Ecosystèmes Insulaires Océaniens (UMR 241) (EIO), Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), Institut de Recherche pour le Développement (IRD)-Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Université de la Nouvelle-Calédonie (UNC), Institut de Recherche pour le Développement (IRD)-Université des Antilles et de la Guyane (UAG)-École des hautes études en sciences sociales (EHESS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de La Réunion (UR)-Université de la Polynésie Française (UPF)-Université de la Nouvelle-Calédonie (UNC)-Institut d'écologie et environnement-Université des Antilles (UA), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), Université de Perpignan Via Domitia (UPVD)-École Pratique des Hautes Études (EPHE), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), and Institut de Recherche pour le Développement (IRD)

Subjects
Marquesas Islands, 0106 biological sciences, Coral, ved/biology.organism_classification_rank.species, Aquatic Science, Biology, 010603 evolutionary biology, 01 natural sciences, Coral ecosystem, Phytoplankton, Terrestrial plant, Ecosystem, Organic matter, 14. Life underwater, Fatty acids, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, Stable isotopes, chemistry.chemical_classification, Ecology, Stable isotope ratio, ved/biology, 010604 marine biology & hydrobiology, Food web, chemistry, 13. Climate action, Benthic zone, Environmental chemistry, [SDE]Environmental Sciences, Sources of organic matter, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

International audience; The purpose of this work is to characterize several potential sources of organic matter (OM) in the Marquesas Islands, French Polynesia, and to understand how these sources contribute to OM pools. Stable isotope (δ 13 C and δ 15 N) and fatty acid (FA) compositions of OM potential sources (algal turf, benthic macroalgae, detrital terrestrial plants (DTP), phytoplankton) and OM pools (sediment (SOM) and particulate organic matter (POM)) were studied in coastal areas in Nuku Hiva Island. Isotope compositions of marine POM (δ 13 C = − 22.5 ± 0.8 ‰; δ 15 N = 12.1 ± 1.1 ‰) and SOM (δ 13 C = − 19.1 ± 0.9 ‰; δ 15 N = 14.4 ± 0.5 ‰) highlighted that OM sources at the base of the local food web had unusually high δ 15 N values. Potential FA markers of diatoms and/or cyanobacteria (20:5ω3 and 16:1ω7) were found in these two OM pools. In addition, coastal SOM also displayed FA markers of bacteria, macroalgae and terrestrial plants. For marine POM, potential macroalgae FA markers were recorded (18:2ω6 and 16:2ω4). The stable isotope mixing model highlighted the major contribution of phytoplankton to the coastal SOM (62%), followed by benthic macroalgae (32%), whereas marine POM was mainly composed of a mixture of algal turf and phytoplankton in similar averaged proportions (38%) but presenting wide variations. Our results as a whole strongly suggest that pelagic-benthic coupled processes drive the characteristics and properties of OM sources.

Published
2020

29. Flying to the moon: Lunar cycle influences trip duration and nocturnal foraging behavior of the wedge-tailed shearwater Ardenna pacifica

Author

Karen Bourgeois, Eric Vidal, Martin Thibault, Anne Lorrain, Sylvain Dromzée, Christophe E. Menkès, Aurélien Prudor, Henri Weimerskirch, Yves Letourneur, Sophie de Grissac, Paco Bustamante, Andreas Ravache, Valerie Allain, Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Université de la Nouvelle-Calédonie (UNC), Pacific community (SPC), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Université de la Nouvelle-Calédonie (UNC), This work was supported by the European Union BEST 2.0 project 'Biopelagos' (grant number 1070–2015) and the Province Nord (grantnumber 15C493). Ecole Doctorale du Pacifique and Université de laNouvelle-Calédonie provided A.R. with a PhD fellowship., La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie]), Université de la Nouvelle Calédonie (UNC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Institut Universitaire de France (IUF), and Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.)

Subjects
0106 biological sciences, Ardenna pacifica, Moonlight, Forage (honey bee), GPS-tracking, Foraging, Stable isotope analyses, Zoology, Aquatic Science, Biology, Nocturnal, 010603 evolutionary biology, 01 natural sciences, Predation, 14. Life underwater, Moon, Ecology, Evolution, Behavior and Systematics, Full moon, 010604 marine biology & hydrobiology, Acl, Lunar phase, Duration (music), [SDE]Environmental Sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

International audience; Lunar phase and illumination are known to affect nocturnal behavior of many organisms, particularly through predator-prey interactions. Visual predators can benefit from higher light levels to increase their activity, while prey may decrease their activity to avoid predation. The lower number of nocturnal seabirds observed on colonies during full moon nights has been mostly interpreted as a predation avoidance strategy. However, it is also possible that shearwaters take advantage of the moon's illumination to feed also at night, and stay at sea to forage during full moon nights. We used miniaturized GPS-loggers to obtain 179 tracks from 99 wedge-tailed shearwaters breeding in New Caledonia, to investigate moonlight effects on individual behavior. Lunar phase significantly predicted self-provisioning trip duration, with individuals performing longer trips around the full moon. However, this relationship was not significant during chick-provisioning trips when adults have to frequently return to the colony. Adults mostly returned to the colony during moonlit periods, refuting the predation avoidance theory. Tracked individuals showed an unexpectedly high amount of nocturnal foraging activity (28% of total activity), positively influenced by the presence of the moon. δ15N stable isotope values were significantly related to the percentage of nocturnal foraging, but with a weak relationship, impeding our ability to confirm that wedge-tailed shearwaters fed on different prey when foraging at night. This study suggests that reduced colony attendance around the full moon may be linked to greater at-sea foraging opportunities in distant oceanic areas than to increased predation risk on land.

Published
2020

30. Behavioral and trophic segregations help the Tahiti petrel to cope with the abundance of wedge-tailed shearwater when foraging in oligotrophic tropical waters

Author

Andreas Ravache, Karen Bourgeois, Henri Weimerskirch, Angélique Pagenaud, Sophie de Grissac, Mark Miller, Sylvain Dromzée, Anne Lorrain, Valérie Allain, Paco Bustamante, Jonas Bylemans, Dianne Gleeson, Yves Letourneur, Éric Vidal, Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Université de la Nouvelle-Calédonie (UNC), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), School of Biology [Leeds], University of Leeds, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), Pacific community (SPC), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), University of Canberra, Université de la Nouvelle-Calédonie (UNC), Cette étude a été principalement soutenue par le projet BEST 2.0 de l'Union européenne 'Biopelagos' (Numéro de subvention 1070-2015 à la CPS), la Province Nord (Numéro de subvention 15C493) et le DAFE-NC (Numéro de subvention 2019/DAFE/873), tandis que l'Ecole Doctorale du Pacifique et l'Université de la Nouvelle-Calédonie ont fourni à A.R. une bourse de doctorat. Le CPER (Contrat de Plan Etat-Région) et le FEDER (Fonds Européen de Développement Régional) ont fourni un financement supplémentaire au laboratoire IRMS of LIENSs et l'IUF (Institut Universitaire de France) est remercié pour son soutien à P. Bustamante en tant que Membre Senior., Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), and La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Stable isotope analysis, Genetic Speciation, Behavioural ecology, lcsh:Medicine, Nutritional Status, Breeding, Article, Birds, Species Specificity, Animals, DNA Barcoding, Taxonomic, lcsh:Science, Ecosystem, Carbon Isotopes, Behavior, Animal, Nitrogen Isotopes, Conservation biology, Acl, lcsh:R, Feeding Behavior, Diet, Sympatry, Predatory Behavior, [SDE]Environmental Sciences, lcsh:Q, Seasons, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

International audience; Two species breeding in sympatry are more likely to coexist if their ecological niches are segregated either in time, space or in trophic habits. Here, we combined GPS-tracking, stable isotope analysis and DNA metabarcoding analysis to understand how the rare Tahiti petrel Pseudobulweria rostrata (TP) copes with the very abundant (i.e. 500,000 breeding pairs) wedge-tailed shearwater Ardenna pacifica (WTS) when breeding in sympatry in a tropical area. WTS foraged in restricted areas along their path, while TP predominantly foraged using extensive search behavior, suggesting a more opportunistic foraging strategy. Interspecific overlap of foraging areas was higher than intraspecific overlap. Breeding seasons largely overlap between species during the study, but TP seems to be asynchronous breeders. TP fed upon prey with higher δ15N values than WTS, and their diet was mainly composed of deep-sea organisms. TP could feed upon dead prey floating at the surface while WTS preyed mainly upon fish species that generally move in schools. Our study highlights several segregating mechanisms (temporal, behavioral and trophic) that could facilitate the coexistence of the two species despite the predominant number of WTS, and provides the very first information on the foraging and trophic ecology of the poorly-known TP.

Published
2020

31. The same but different: stable isotopes reveal two distinguishable, yet similar, neighbouring food chains in a coral reef

Author

Benoit Lebreton, Jean Blanchot, Baptiste Le Bourg, Daniela Bănaru, Gérard Mou-Tham, Yves Letourneur, Marc Pagano, Cristèle Chevalier, Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Université de la Nouvelle-Calédonie (UNC), Institut de Recherche pour le Développement (IRD), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), and La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
zooplankton, 0106 biological sciences, stable isotopes, chemistry.chemical_element, Aquatic Science, 010603 evolutionary biology, 01 natural sciences, Zooplankton, Food chain, reef teleosts, 14. Life underwater, particulate organic matter, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Trophic level, geography, Pacific Ocean, geography.geographical_feature_category, Particulate organic matter, Ecology, Chemistry, Stable isotope ratio, 010604 marine biology & hydrobiology, fungi, Coral reef, Plankton, Oceanography, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, barrier reef, Carbon
Abstract

Stable isotope compositions were studied in particulate organic matter (POM), zooplankton and different trophic groups of teleosts to compare food chains based on plankton at two sites (lagoon and outer slope) in a New Caledonian coral reef. For each trophic compartment, δ13C values were always lower in the outer slope than in the lagoon. This result may be explained by potential differences in POM composition between the two environments, suggesting that the two food chains are based on different primary sources of carbon. In contrast, δ15N values did not vary between the lagoon and the outer slope, indicating that these two food chains presented similar length and trophic levels, despite being distinguishable.

Published
2017

32. Does trophic level drive organic and metallic contamination in coral reef organisms?

Author

Yves Letourneur, Manon Mercader, Pauline Fey, B. Espiau, Paco Bustamante, P. Bosserelle, A. Malau, E. Wafo, Institut de sciences exactes et appliquées (ISEA), Université de la Nouvelle-Calédonie (UNC), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Pacific community (SPC), Service de l'Environnement - Préfecture des îles Wallis et Futuna, Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Membranes et cibles thérapeutiques (MCT), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Recherche Biomédicale des Armées [Brétigny-sur-Orge] (IRBA), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Recherche Biomédicale des Armées (IRBA), Laboratoire d'Ecologie Marine (ECOMAR), Université de La Réunion (UR), and Bustamante, Paco

Subjects
Aquatic Organisms, Food Chain, Environmental Engineering, 010504 meteorology & atmospheric sciences, Biomagnification, [SDV]Life Sciences [q-bio], trace elements, 010501 environmental sciences, 01 natural sciences, Polynesia, nitrogen stable isotope, New Caledonia, Animals, Environmental Chemistry, [CHIM]Chemical Sciences, Organic matter, 14. Life underwater, PCBs, Organic Chemicals, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Trophic level, chemistry.chemical_classification, geography, [SDV.TOX.ECO] Life Sciences [q-bio]/Toxicology/Ecotoxicology, geography.geographical_feature_category, Coral Reefs, Trace element, Coral reef, pesticides, Pesticide, Polychlorinated Biphenyls, Pollution, biomagnification, chemistry, Metals, 13. Climate action, Benthic zone, Bioaccumulation, Environmental chemistry, Bass, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology, Serranidae, bioreduction, Water Pollutants, Chemical
Abstract

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.

Published
2019

33. A Model of Mercury Distribution in Tuna from the Western and Central Pacific Ocean: Influence of Physiology, Ecology and Environmental Factors

Author

Yves Letourneur, Patrick Houssard, Jérémy Masbou, Christelle Lagane, Laura Tremblay-Boyer, Valerie Allain, Anne Lorrain, Bridget E. Ferriss, Heidi Pethybridge, David Point, Pascale Anabelle Baya, Christophe E. Menkès, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de la Nouvelle-Calédonie (UNC), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Pacific community (SPC), CSIRO Marine and Atmosphere Research [Hobart], Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Northwest Fisheries Science Center (NWFSC), NOAA National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Institut de Recherche pour le Développement (IRD), ANR-17-CE34-0010,MERTOX,Découvrir l'origine de la toxine methylmercure dans les écosystèmes marins(2017), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
MARINE FISH, Oceans and Seas, TROPHIC POSITION, chemistry.chemical_element, Bigeye tuna, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 010501 environmental sciences, Physical oceanography, METHYLMERCURY, 01 natural sciences, ALBACARES, Hawaii, Latitude, chemistry.chemical_compound, Environmental Chemistry, Animals, Humans, 14. Life underwater, Methylmercury, 0105 earth and related environmental sciences, Trophic level, Pacific Ocean, biology, Albacore, Tuna, ACL, BIGEYE TUNA, METHYLATION, General Chemistry, Mercury, BIOACCUMULATION, biology.organism_classification, Mercury (element), PELAGIC FISHES, Oceanography, chemistry, YELLOWFIN, THUNNUS-OBESUS, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

Information on ocean scale drivers of methylmercury levels and variability in tuna is scarce, yet crucial in the context of anthropogenic mercury (Hg) inputs and potential threats to human health. Here we assess Hg concentrations in three commercial tuna species (bigeye, yellowfin, and albacore, n = 1000) from the Western and Central Pacific Ocean (WCPO). Models were developed to map regional Hg variance and understand the main drivers. Mercury concentrations are enriched in southern latitudes (10 degrees S-20 degrees S) relative to the equator (0 degrees-10 degrees S) for each species, with bigeye exhibiting the strongest spatial gradients. Fish size is the primary factor explaining Hg variance but physical oceanography also contributes, with higher Hg concentrations in regions exhibiting deeper thermoclines. Tuna trophic position and oceanic primary productivity were of weaker importance. Predictive models perform well in the Central Equatorial Pacific and Hawaii, but underestimate Hg concentrations in the Eastern Pacific. A literature review from the global ocean indicates that size tends to govern tuna Hg concentrations, however regional information on vertical habitats, methylmercury production, and/or Hg inputs are needed to understand Hg distribution at a broader scale. Finally, this study establishes a geographical context of Hg levels to weigh the risks and benefits of tuna consumption in the WCPO.

Published
2019

34. Differential uses of coral reef habitats by a poorly‐known cryptic fish predator

Author

Christophe Pécheyran, Marine J. Briand, Yves Letourneur, Fabien Morat, Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de la Nouvelle-Calédonie (UNC), The Total Foundation and the Ecole Doctorale du Pacifique. Grant Number: ED 469, and Université de Perpignan Via Domitia (UPVD)-École Pratique des Hautes Études (EPHE)

Subjects
0106 biological sciences, Water mass, Gymnothorax chilospilus, Fringing reef, Zoology, trace elements, Aquatic Science, Biology, 010603 evolutionary biology, 01 natural sciences, Otolithic Membrane, New Caledonia, otolith, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, medicine, Animals, 14. Life underwater, Moray eel, Muraenidae, Reef, Ecology, Evolution, Behavior and Systematics, Ecosystem, Otolith, geography, Larva, geography.geographical_feature_category, Eels, Behavior, Animal, 010604 marine biology & hydrobiology, Coral reef, [CHIM.MATE]Chemical Sciences/Material chemistry, biology.organism_classification, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, medicine.anatomical_structure, [CHIM.POLY]Chemical Sciences/Polymers, Seafood, Multivariate Analysis, coral reefs
Abstract

International audience; This study used otolith microchemistry to evaluate whether the moray eel Gymnothorax chilospilus uses different habitats throughout its life (mainly juvenile and adult phases). Of the most informative trace elements within otoliths (the twelve isotopes 23Na, 25Mg, 43Ca, 55Mn, 59Co, 60Ni, 63Cu, 66Zn, 86Sr, 111Cd, 138Ba and 208Pb) only three ratios of Ca (Na:Ca, Sr:Ca and Ba:Ca) were informative and therefore used in a multivariate regression-tree analysis. Using a multivariate partitioning, three main phases were described from profiles, including the larval life phase (leptocephali), the intermediate phase (longest section between the larval life phase and the terminal phase) and the terminal phase (final section i.e., the most recent months preceding the death of fish). According to concentrations of the three ratios to Ca, G. chilospilus can be separated into three groups during their larval life stage (very different in Sr and Na), four groups during the intermediate phase (few differences in Sr and Na) and three groups during the terminal phase (differences in Sr), illustrating that G. chilospilus inhabit different habitats during these three phases. Our results showed that the leptocephali encountered different oceanic water masses with fluctuating Sr:Ca ratios during the early larval phase. During the intermediate phase (main part of their life-span), they lived in lagoonal waters such as fringing reefs or reef flats of lagoonal islets, characterized by a lower Sr:Ca ratio. During the latter part of their life, approximately one third of G. chilospilus encountered more oceanic waters close to or at barrier reefs, suggesting possible movements of these fish along a coast-to-ocean gradient.

Published
2019

35. Assimilation of shrimp farm sediment by Holothuria scabra: a coupled fatty acid and stable isotope approach

Author

Edouard Kraffe, Yves Letourneur, Margaux Mathieu-Resuge, Anne Lorrain, Julie Benoit, Hugues Lemonnier, Sébastien Hochard, Fabienne Le Grand, Gauthier Schaal, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Université de la Nouvelle-Calédonie (UNC), Université de la Nouvelle-Calédonie (UNC), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Agence de Développement Economique de la Nouvelle-Calédonie, This research was financed by the ZONECO program of New Caledonia and the Ministry of Overseas Territories (Ministere de l'Outre Mer). We thankFlorence Royer and Morgane Hubert for their helpful participation in the sample acquisition and preparation. The LIPIDOCEAN analytical facility (University of Western Brittany, France) is acknowledged for hosting all fatty acids analyses., Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC)

Subjects
0106 biological sciences, [SDV]Life Sciences [q-bio], stable isotopes, shrimp-farming, Aquatic Science, 01 natural sciences, Holothuria scabra, Shrimp farming, Nutrient, Fish meal, Aquaculture, Sedimentary organic matter, Organic matter, 14. Life underwater, Fatty acids, Holothurid, 2. Zero hunger, chemistry.chemical_classification, biology, business.industry, ACL, 010604 marine biology & hydrobiology, 04 agricultural and veterinary sciences, biology.organism_classification, rotational co-culture, Shrimp, Agronomy, chemistry, 040102 fisheries, 0401 agriculture, forestry, and fisheries, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, business
Abstract

Deposit-feeding sea cucumbers are efficient nutrient recyclers and have the potential to contribute to the limitation of organic matter load in polyculture or integrated aquaculture systems. Assessing how they assimilate organic matter originating from other farmed species is therefore important for the development of such multi-species farming systems. Here, a coupled stable isotope − fatty acid approach was used to characterize the assimilation of organic matter from shrimp (Penaeus stylirostris) farming by Holothuria scabra in an experimental culture system. H. scabra were reared in mesocosms on shrimp farming-originating sediment with and without additional food sources (maize and fish meals). Although fatty acid results did indicate that shrimp-farming sediment was assimilated by holothurids, we found no evidence of maize waste and fish meal contribution to H. scabra organic carbon (no effect on δ13C, no accumulation of meal-specific fatty acids). However, a strong effect of fish meal on H. scabra δ15N was observed, suggesting that this additional food source could represent an alternative source of nitrogen for holothurids. Finally, this study supports the culture of H. scabra as a perspective to reduce sedimentary organic matter excess associated with shrimp farms, and suggest that the addition of selected food sources might contribute to increasing the content in some nitrogen organic compounds in holothurid tissues.

Published
2020

36. A lack of spatial genetic structure of Gymnothorax chilospilus (moray eel) suggests peculiar population functioning

Author

Nicolas Bech, François Brischoux, Yves Letourneur, Xavier Bonnet, Cécile Ribout, D Guyonnet, Marine J. Briand, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Ecologie et biologie des interactions (EBI), Université de Poitiers-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Danone Research, Groupe DANONE, Université de la Nouvelle-Calédonie (UNC), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), Université de la Nouvelle Calédonie (UNC), and Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, education.field_of_study, biology, 010604 marine biology & hydrobiology, Population, Zoology, biology.organism_classification, Gymnothorax chilospilus, 010603 evolutionary biology, 01 natural sciences, microsatellites, larval stage, New Caledonia, Genetic structure, [SDE]Environmental Sciences, 454 pyrosequencing, 14. Life underwater, Moray eel, education, Muraenidae, dispersal, Ecology, Evolution, Behavior and Systematics
Abstract

International audience; Moray eels form a speciose lineage that belongs to Elopomorpha, a super-order with a worldwide distribution.As is the case for many anguilliform fish, moray eels are characterized by distinctive life history traits, notably aprolonged larval dispersal phase that determines settlement to distant reef habitats, thus influencing the spatialstructuring of their populations. They can be very abundant in coral reef ecosystems and represent major mesopredators,playing a crucial role in food webs. Yet, due to their elusive nature (i.e. cryptic behaviour, nocturnalactivity), these organisms are generally difficult to study and collect. To our knowledge, only a few studies performedover large geographical and phylogenetic scales have been conducted. We used a unique and cost-efficientsampling approach, involving forced regurgitation from sea snake predators, to collect large numbers of a widespreadmoray eel species (Gymnothorax chilospilus). When combined with the development of 11 new microsatellitemarkers, this efficient sampling technique allowed us to examine the genetic structure of Gymnothoraxpopulations occurring in the South Lagoon of New Caledonia. Analyses revealed a lack of genetic differentiationamong populations. This result echoes the strong genetic homogeneity of populations of their main predator, thesea snake. This convergence might result from a distinctive trait involved in population functioning of both morayeels and sea snakes, where immature individuals emerge from common breeding grounds and disperse over longdistances before settlement.

Published
2018

38. Tracking trace elements into complex coral reef trophic networks

Author

Paco Bustamante, Xavier Bonnet, Carine Churlaud, Yves Letourneur, Marine J. Briand, Laboratoire Insulaire du Vivant et de l'Environnement (LIVE), Université de la Nouvelle-Calédonie (UNC), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
0106 biological sciences, Food Chain, Environmental Engineering, metallic contamination, 010501 environmental sciences, 01 natural sciences, New Caledonia, Environmental Chemistry, Sedimentary organic matter, Ecosystem, 14. Life underwater, Waste Management and Disposal, Reef, 0105 earth and related environmental sciences, Trophic level, Biomagnification, geography, geography.geographical_feature_category, Coral Reefs, Ecology, 010604 marine biology & hydrobiology, Trace element, Coral reef, Pollution, Food web, Trace Elements, trophic compartments, bioaccumulation, Benthic zone, food webs, Environmental science, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology, Water Pollutants, Chemical, Environmental Monitoring
Abstract

International audience; The integration, accumulation and transfer of trace elements across the main tropic levels of many food webs are poorly documented. This is notably the case for the complex trophic webs of coral reef ecosystems. Our results concerning the south-west lagoon of New Caledonia show that both abiotic (i.e. sediments) and biotic (i.e. primary producers, consumers and predators) compartments are generally contaminated by trace elements. However, our analyses revealed specific contamination patterns from the sources of organic matter to predators. The trophic levels involved in the sedimentary benthic food web (S-BFW - based on the sedimentary organic matter) and to a lesser extent in the reef benthic food web (R-BFW - based on algal turf) were mainly contaminated by trace elements that originate from mining activities: Ni and associated trace elements (Co, Cr, Fe, and Mn) were preferentially integrated into these trophic structures. Trace elements linked to agro-industrial (As, Hg, and Zn) and urban (Ag, Cd, Cu, Pb, Se, and V) activities were also integrated into the S-BFW, but preferentially into the R-BFW, and to a lesser extent into the detrital benthic food web (D-BFW) supplied by sea-grass plants. Most of the trace elements were biodiminished with increasing trophic levels along trophic networks. However, a marked biomagnification was observed for Hg, and suspected for Se and Zn. These results provide important baseline information to better interpret trace element contamination in the different organisms and trophic levels in a highly diversified coral reef lagoon.

Published
2018

39. Coral reef degradation alters the isotopic niche of reef fishes

Author

Marine J. Briand, Nicholas A. J. Graham, Yves Letourneur, Laboratoire Insulaire du Vivant et de l'Environnement (LIVE), Université de la Nouvelle-Calédonie (UNC), Aix-Marseille Université - Faculté de droit et de science politique - Pôle maritime, aérien et des transports ( AMU Pôle transports CDMT IFURTA), Aix Marseille Université (AMU), Lancaster Environment Centre, and Lancaster University

Subjects
0106 biological sciences, geography, geography.geographical_feature_category, Ecology, biology, Resilience of coral reefs, Coral reef fish, 010604 marine biology & hydrobiology, Coral, Niche, Coral reef, 15. Life on land, Aquatic Science, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Fishery, Habitat destruction, Halichoeres melanurus, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Reef, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS
Abstract

The degradation of coral reefs is widely reported, yet there is a poor understanding of the adaptability of reef fishes to cope with benthic change. We tested the effects of coral reef degradation on the feeding plasticity of four reef fish species. We used isotopic niche sizes and mean δ15N and δ13C values of each species in two coral reefs that differed in benthic condition. The species chosen have contrasting feeding strategies; Chaetodon lunulatus (corallivore), Chrysiptera rollandi (zooplanktivore), Halichoeres melanurus (invertivore) and Zebrasoma velifer (herbivore). We predicted that the corallivore would have a lower mean δ15N value and a smaller isotopic niche size in the degraded reef, that the herbivore and the invertivore might have a larger isotopic niche size and/or a different mean δ13C value, whereas the zooplanktivore might be indifferent since the species is not linked to coral degradation. Some results matched our predictions; C. lunulatus had a smaller niche size on the degraded reef, but no difference in mean δ15N and δ13C values, and H. melanurus displayed an increase in niche size and a lower mean δ15N value on the degraded reef. Some other results were contrary to our predictions; whereas Z. velifer and C. rollandi had smaller mean δ13C values but no difference in niche size. Our findings suggest there may be feeding plasticity to maintain a similar diet despite contrasting habitat characteristics, with different amplitude depending on species. Such findings suggest that certain species guilds would probably adapt to changes linked to habitat degradation.

Published
2017

40. Trophic position increases with thermocline depth in yellowfin and bigeye tuna across the Western and Central Pacific Ocean

Author

Aurore Receveur, Lydie I. E. Couturier, Heidi Pethybridge, Jean-Marie Munaron, Elodie Vourey, Yves Letourneur, Patrick Raimbault, Brittany S. Graham, Tsuguo Otake, Sophie Bonnet, Eric Feunteun, Laura Tremblay-Boyer, Valerie Allain, Anne Lorrain, Petra M. Kuhnert, Christophe E. Menkès, Brian P. V. Hunt, Martine Rodier, Bruno Leroy, Benoit Lebreton, Patrick Houssard, David Point, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Insulaire du Vivant et de l'Environnement (LIVE), Université de la Nouvelle-Calédonie (UNC), Institut de Recherche pour le Développement (IRD), Pacific community (SPC), National Institute of Water and Atmospheric Research [Wellington] (NIWA), Processus de couplage à Petite Echelle, Ecosystèmes et Prédateurs Supérieurs (PEPS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CSIRO Marine and Atmosphere Research [Hobart], Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), University of British Columbia (UBC), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Institut de Recherche pour le Développement (IRD [Polynésie]), Ecosystèmes Insulaires Océaniens (UMR 241) (EIO), Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), Institut de Recherche pour le Développement (IRD)-Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Station marine Dinard, Centre National de la Recherche Scientifique (CNRS), Data61 [Canberra] (CSIRO), Australian National University (ANU)-Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), The University of Tokyo (UTokyo), GOPS HISPANIC, PACIMER, the Pacific Fund VACOPA project, Government of New Caledonia, BIOPELAGOS project funded by the European Union BEST 2.0 Programme, ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), Laboratoire des Sciences de l'Environnement Marin (LEMAR) ( LEMAR ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Brest ( UBO ) -Institut Français de Recherche pour l'Exploitation de la Mer ( IFREMER ) -Institut Universitaire Européen de la Mer ( IUEM ), Institut de Recherche pour le Développement ( IRD ) -Université de Brest ( UBO ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ) -Université de Brest ( UBO ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ), Laboratoire Insulaire du Vivant et de l'Environnement ( LIVE ), Université de la Nouvelle-Calédonie, Secretariat of the Pacific Community ( Secretariat of the Pacific Community ), Secretariat of the Pacific Community, National Institute of Water and Atmospheric Research [Wellington] ( NIWA ), Processus de couplage à Petite Echelle, Ecosystèmes et Prédateurs Supérieurs ( PEPS ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques ( LOCEAN ), Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), CISRO Oceans and Atmosphere, Géosciences Environnement Toulouse ( GET ), Institut de Recherche pour le Développement ( IRD ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), University of British Columbia ( UBC ), Institut méditerranéen d'océanologie ( MIO ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Toulon ( UTLN ) -Aix Marseille Université ( AMU ) -Institut de Recherche pour le Développement ( IRD ), Institut de Recherche pour le Développement ( IRD [Polynésie] ), Ecosystèmes Insulaires Océaniens (UMR 241) ( EIO ), Institut de Recherche pour le Développement ( IRD ) -Institut Français de Recherche pour l'Exploitation de la Mer ( IFREMER ) -Institut Louis Malardé [Papeete] ( ILM ), Institut de Recherche pour le Développement ( IRD ) -Université de la Polynésie Française ( UPF ), Biologie des Organismes et Ecosystèmes Aquatiques ( BOREA ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Muséum National d'Histoire Naturelle ( MNHN ) -Institut de Recherche pour le Développement ( IRD ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université des Antilles ( UA ), Centre National de la Recherche Scientifique ( CNRS ), LIttoral ENvironnement et Sociétés - UMR 7266 ( LIENSs ), Université de La Rochelle ( ULR ) -Centre National de la Recherche Scientifique ( CNRS ), The University of Tokyo, ANR-10-LABX-0019/10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean ( 2010 ), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Centre De Recherche et d'Enseignement sur les Systèmes Côtiers (CRESCO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)

Subjects
0106 biological sciences, Delta, Yellowfin tuna, 010504 meteorology & atmospheric sciences, Mesopelagic zone, Depth of the 20°C isotherm, Bigeye tuna, Aquatic Science, 01 natural sciences, [ SDV.EE ] Life Sciences [q-bio]/Ecology, environment, Isoscapes Bigeye tuna, Compound-specific isotope analysis, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Trophic level, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, POM, biology, Depth of the 20 degrees C isotherm, 010604 marine biology & hydrobiology, Nitrogen isotopes, ACL, Biochemical markers, food and beverages, Geology, biology.organism_classification, Food web, Amino acid, Fishery, Oceanography, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Tuna, Thermocline, human activities
Abstract

International audience; Estimates of trophic position are used to validate ecosystem models and understand food web structure. A consumer's trophic position can be estimated by the stable nitrogen isotope values (delta N-15) of its tissue, once the baseline isotopic variability has been accounted for. Our study established the first data-driven baseline delta N-15 isoscape for the Western and Central Pacific Ocean using particulate organic matter. Bulk delta N-15 analysis on 1039 muscle tissue of bigeye and yellowfin tuna were conducted together with amino acid compound-specific delta N-15 analysis (AA-CSIA) on a subset of 21 samples. Both particulate organic matter and tuna bulk delta N-15 values varied by more than 10 parts per thousand across the study area. Fine-scaled trophic position maps were constructed and revealed higher tuna trophic position (by similar to 1) in the southern latitudes compared to the equator. AA-CSIA confirmed these spatial patterns for bigeye and, to a lesser extent, yellowfin tuna. Using generalized additive models, spatial variations of tuna trophic positions were mainly related to the depth of the 20 degrees C isotherm, a proxy for the thermocline behavior, with higher tuna trophic position estimates at greater thermocline depths. We hypothesized that a deeper thermocline would increase tuna vertical habitat and access to mesopelagic prey of higher trophic position. Archival tagging data further suggested that the vertical habitat of bigeye tuna was deeper in the southern latitudes than at the equator. These results suggest the importance of thermocline depth in influencing tropical tuna diet, which affects their vulnerability to fisheries, and may be altered by climate change.

Published
2017

41. Pathways of organic matter in an estuarine mangrove trophic network assessed by carbon and nitrogen stable isotopes

Author

Marine J. Briand, Yves Letourneur, Gaël Guillou, Institut de sciences exactes et appliquées (ISEA), and Université de la Nouvelle-Calédonie (UNC)

Subjects
0106 biological sciences, chemistry.chemical_classification, biology, Ecology, 010604 marine biology & hydrobiology, [SDV]Life Sciences [q-bio], 15. Life on land, Aquatic Science, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Food web, Food chain, chemistry, Avicennia marina, [SDE]Environmental Sciences, Environmental science, Sedimentary organic matter, Organic matter, Ecosystem, 14. Life underwater, Mangrove, Trophic level
Abstract

Carbon and nitrogen stable isotopes were used to describe an estuarine mangrove food web in New Caledonia, SW Pacific. Isotopic values were measured for all components of the ecosystem, from various organic matter (OM) sources to predators. Primary producers showed δ13C values from −32.29‰ (Bruguiera gymnorhiza) to −24.67‰ (mouth particulate organic matter), whereas δ15N values ranged from 1.48‰ (Avicennia marina) to 10.17‰ (Eichomia crassipes). Two potential organic matter sources, i.e. the mangrove species and E. crassipes, appeared not to be directly used by consumers although were indirectly entering the food web through particulate and sedimentary organic matter pools (POM and SOM). Overall, invertebrates showed C-depleted and N-depleted values compared with fish, highlighting their lower trophic level. The highest trophic levels in this estuarine mangrove were represented by carangids (δ15N of 11.24‰ for Caranx sp. and 10.81‰ for Carangoides fulvoguttatus) and gerrids (δ15N of 10.42‰ for Gerres filamentosus). Two main pathways of organic matter were identified from sources of OM to end-members, i.e. from estuarine POM and SOM toward gerrids and from marine POM towards carangids. The food chain comprised three or four trophic levels, depending on the pathway of organic matter. The position of some consumer species within the reconstructed food web might imply that an important source of organic matter was probably missing, i.e. microphytobenthos. Despite an obvious connection, the role of river inputs as potential drivers of mangrove food web dynamics appeared important only during the wet season.

Published
2017

42. Effects of blue shrimp Litopenaeus stylirostris and goldlined rabbitfish Siganus lineatus in mono- and polyculture on production and environmental conditions

Author

Florence Royer, Yves Letourneur, Hugues Lemonnier, Sébastien Hochard, Trung Cong Luong, Institut de sciences exactes et appliquées (ISEA), Université de la Nouvelle-Calédonie (UNC), Laboratoire Insulaire du Vivant et de l'Environnement (LIVE), and BUNC, Pole ID

Subjects
[SDE] Environmental Sciences, 0301 basic medicine, Penaeidae, [SDV]Life Sciences [q-bio], Biomass, Aquatic Science, Mesocosm, 03 medical and health sciences, Siganidae, Animal science, carrying capacity, 14. Life underwater, Polyculture, pond ecology, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, biology, 04 agricultural and veterinary sciences, biology.organism_classification, Shrimp, [SDV] Life Sciences [q-bio], Fishery, 030104 developmental biology, integrated production, [SDE]Environmental Sciences, 040102 fisheries, polyculture, 0401 agriculture, forestry, and fisheries, Monoculture, Eutrophication, Rabbitfish
Abstract

This study was conducted to compare the effects of shrimp and rabbitfish in mono- and polyculture stocked at high biomass on production and environmental conditions in a mesocosm system. Shrimp (14 g) and/or rabbitfish (19 g) were stocked in four treatments with different density but with the same total biomass (236 g m−2), including shrimp monoculture (SM) (17 shrimp m−2), shrimp–fish polyculture (SF) (11 shrimp and 4 rabbitfish m−2), fish–shrimp polyculture (FS) (6 shrimp and 8 rabbitfish m−2) and fish monoculture (FM) (12 rabbitfish m−2). After 10 weeks of experiment, shrimp survival and biomass were low in the treatments where shrimp were dominant (SM, SF), while rabbitfish survival and biomass were high in all the treatments. Shrimp mortality was assumed to be related to an excess of the system carrying capacity (CC). Results suggested that CC is linked to shrimp biomass/density rather than the system eutrophication level. The ecosystem became heterotrophic as daily feed supply was beyond 7 g m−2 per day. This threshold corresponded to the environmental CC of the semi-intensive shrimp culture system. Under these conditions, the combination of high fish biomass and low shrimp biomass appeared as the most valuable in terms of system performances.

Published
2017

43. First record of Siganus randalli (Teleost, Siganidae) in New Caledonia, and comments on its diet

Author

Thibaud Moléana, Yves Letourneur, Luc Della Patrona, Tarik Meziane, Laboratoire d'Excellence CORAIL (LabEX CORAIL), Université des Antilles (UA)-Institut d'écologie et environnement-Université de la Nouvelle-Calédonie (UNC)-Université de la Polynésie Française (UPF)-Université de La Réunion (UR)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École des hautes études en sciences sociales (EHESS)-Université des Antilles et de la Guyane (UAG)-Institut de Recherche pour le Développement (IRD), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Recherche pour le Développement (IRD)-Université des Antilles et de la Guyane (UAG)-École des hautes études en sciences sociales (EHESS)-École Pratique des Hautes Études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de La Réunion (UR)-Université de la Polynésie Française (UPF)-Université de la Nouvelle-Calédonie (UNC)-Institut d'écologie et environnement-Université des Antilles (UA)

Subjects
0106 biological sciences, SW pacific, Ecology, Range (biology), Isotope, 010604 marine biology & hydrobiology, Stomach content, [SDV.BID]Life Sciences [q-bio]/Biodiversity, Aquatic Science, Biology, Oceanography, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Diet, Fishery, Habitat, Variegated rabbitfish, 14. Life underwater, Siganus randalli, Mangrove, Ecology, Evolution, Behavior and Systematics, Rabbitfish
Abstract

International audience; Background: Most of the 29 Siganidae species are widely distributed through the Indo-Pacific area. In New Caledonia, these family was represented by 12 species. The present report is the first record of Siganus randalli in New Caledonian waters and provide information on its diet. Methods: Three specimens of Siganus randalli were caught in shallow mangrove waters of the southern part of New Caledonia. Their stomach contents and isotopic signatures (carbon and nitrogen) were analyzed and compared to others siganids species. Results and conclusion: This note provides the most southerly record of the rabbitfish Siganus randalli, which extends its distribution range by 1200 km southward and 1300 km southwest. The data on its diet, when compared with other co-occurring or more reef-associated siganid species, provide information on feeding processes and ecological functions associated with its mangrove habitat.

Published
2016

44. Marine reserve spillover: Modelling from multiple data sources

Author

Yves Letourneur, Pascal Monestiez, Frédéric Bachet, Patrick Bonhomme, Laurence Ledireach, Philipp Neubauer, Edwige Bellier, Biostatistique et Processus Spatiaux (BIOSP), Institut National de la Recherche Agronomique (INRA), Biostatistique et Processus Spatiaux (BioSP), Provence Alpes Cotes d'Azur province, Institut National pour la Recherche Agronomique (INRA), and Norwegian Research Council (NRC)

Subjects
0106 biological sciences, exponential decreasing, spatial generalized linear mixed model, Spatial distribution, Bayesian inference, 010603 evolutionary biology, 01 natural sciences, Generalized linear mixed model, harvested species, Spillover effect, Abundance (ecology), Statistics, Econometrics, 14. Life underwater, Spatial analysis, Ecology, Evolution, Behavior and Systematics, bayesian inference, Ecology, biology, multiple data sources, 010604 marine biology & hydrobiology, Applied Mathematics, Ecological Modeling, Model selection, Diplodus, biology.organism_classification, Computer Science Applications, Computational Theory and Mathematics, Modeling and Simulation, [SDE]Environmental Sciences, latent density, Environmental science, functional form
Abstract

International audience; The functional formof spillover,measured as a gradient of abundance of fish,may provide insight about processes that control the spatial distribution of fish inside and outside theMPA. In this study,we aimed to infer on spillover mechanism of Diplodus spp. (family Sparidae) from a Mediterranean MPA (Carry-le-Rouet, France) from visual censuses and artisanal fisheries data. From the existing literature, three potential functional forms of spillover such as a linear gradient, an exponential gradient and a logistic gradient are defined. Each functional form is included in a spatial generalized linear mixed model allowing accounting for spatial autocorrelation of data. We select between the different forms of gradients by using a Bayesian model selection procedure. In a first step, the functional form of the spillover for visual census and artisanal fishing data is assessed separately. For both sets of data, ourmodel selection favoured the negative exponentialmodel, evidencing a decrease of the spatial abundance of fish vanishing around 1000 m from the MPA border. We combined both datasets in a joint model by including an observability parameter. This parameter captures how the different sources of data quantify the underlying spatial distribution of the harvested species. This enabled us to demonstrate that the different sampling methods do not affect the estimation of the underlying spatial distribution of Diplodus spp. inside and outside the MPA. We show that data from different sources can be pooled through spatial generalized linear mixedmodel. Our findings allow to better understand the underlying mechanisms that control spillover of fish from MPA.

Published
2013

45. Complex food webs in highly diversified coral reefs: Insights from δ13C and δ15N stable isotopes

Author

Xavier Bonnet, Marine J. Briand, Gaël Guillou, Yves Letourneur, Laboratoire Insulaire du Vivant et de l'Environnement (LIVE), Université de la Nouvelle-Calédonie (UNC), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire LIVE, Université de la Nouvelle Calédonie (UNC), Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs)

Subjects
0106 biological sciences, Organic matter sources, 010603 evolutionary biology, 01 natural sciences, Predatory fish, New Caledonia, 14. Life underwater, Reef, Ecology, Evolution, Behavior and Systematics, Trophic level, geography, geography.geographical_feature_category, Ecology, biology, 010604 marine biology & hydrobiology, Pelagic zone, Coral reef, Isotopic ratios, biology.organism_classification, Food web, Fishery, Predators, Seagrass, Benthic zone, [SDE]Environmental Sciences, Trophic networks, Consumers
Abstract

International audience; We studied the trophic network architecture of the coral reef ecosystem of the New Caledonian lagoon. To encompass the main tropic levels, we assayed carbon and nitrogen stable isotopes in various organic matter sources, intermediate consumers (invertebrates and fish), and 19 species of predatory fish (total of 1229 samples). At each level, wide range of variations for δ13C and δ15N suggested multiple sources for the OM, and complex trophic relationships among the different organisms. Despite this complexity, four trophic structures were identified. 1) The predominant reef benthic food web (R-BFW) based on the OM produced by algal turf supplies most of intermediate consumers and all anguilliform fish studied. 2) The sedimentary benthic food web (S-BFW), and 3) the lagoon pelagic food web (L-PFW), respectively based on sedimentary OM (SOM) and particulate OM (POM) involve a wide range of organisms and represent complementary food webs for most anguilliform fish. 4) Finally, the detrital benthic food web (D-BFB) where the OM issued from seagrass is indirectly utilised by reef consumers plays a secondary role. Anguilliform fish are widespread sedentary predators that live in various habitats; the species sampled were respectively associated with the three main trophic structures identified, depending on their diet and habitat. This study reveals several major structures that are inter-connected to form an overall complex trophic network in the coral reefs.

Published
2016

46. Seagrass beds as feeding territory for farming Stegastes spp (Pomacentridae)

Author

Alexis Cuvilier, Henrich J. Bruggemann, Yves Letourneur, Ludovic Hoarau, Patrick Frouin, Laboratoire Insulaire du Vivant et de l'Environnement (LIVE), Université de la Nouvelle-Calédonie (UNC), Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Institut de Recherche pour le Développement (IRD), Délégation Ifremer océan indien, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), and BUNC, Pole ID

Subjects
0106 biological sciences, biology, business.industry, 010604 marine biology & hydrobiology, [SDE.MCG]Environmental Sciences/Global Changes, Stegastes, Biodiversity, Pomacentridae, Aquatic Science, Oceanography, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Fishery, [SDE.BE] Environmental Sciences/Biodiversity and Ecology, [SDE.MCG] Environmental Sciences/Global Changes, Geography, Seagrass, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Agriculture, [SDV.EE.ECO] Life Sciences [q-bio]/Ecology, environment/Ecosystems, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, business, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016

47. Extinction vulnerability of coral reef fishes

Author

Richard D. Evans, Nicholas A. J. Graham, Marcus C. Öhman, Pascale Chabanet, Yves Letourneur, Tim R. McClanahan, Simon Jennings, M. Aaron MacNeil, Shaun K. Wilson, Nicholas Polunin, Laboratoire Insulaire du Vivant et de l'Environnement (LIVE), and Université de la Nouvelle-Calédonie (UNC)

Subjects
0106 biological sciences, Conservation of Natural Resources, Climate Change, [SDV]Life Sciences [q-bio], Population Dynamics, Fisheries, Biodiversity, Vulnerability, synergy, Biology, Extinction, Biological, 010603 evolutionary biology, 01 natural sciences, ecosystem function, Animals, natural sciences, Letters, additive effects, 14. Life underwater, resilience, Reef, Ecology, Evolution, Behavior and Systematics, ecosystem, function, geography, geography.geographical_feature_category, Extinction, Coral Reefs, Ecology, 010604 marine biology & hydrobiology, fungi, Marine reserve, Fishes, technology, industry, and agriculture, social sciences, Coral reef, 15. Life on land, multiple stressors, climate change, Habitat destruction, 13. Climate action, fisheries, coral reef ecology, Fisheries management, geographic locations
Abstract

With rapidly increasing rates of contemporary extinction, predicting extinction vulnerability and identifying how multiple stressors drive non-random species loss have become key challenges in ecology. These assessments are crucial for avoiding the loss of key functional groups that sustain ecosystem processes and services. We developed a novel predictive framework of species extinction vulnerability and applied it to coral reef fishes. Although relatively few coral reef fishes are at risk of global extinction from climate disturbances, a negative convex relationship between fish species locally vulnerable to climate change vs. fisheries exploitation indicates that the entire community is vulnerable on the many reefs where both stressors co-occur. Fishes involved in maintaining key ecosystem functions are more at risk from fishing than climate disturbances. This finding is encouraging as local and regional commitment to fisheries management action can maintain reef ecosystem functions pending progress towards the more complex global problem of stabilizing the climate.

Published
2011

48. Effects of fisheries closure size, age, and history of compliance on coral reef fish communities in the western Indian Ocean

Author

Nicholas A. J. Graham, Yves Letourneur, Shaun K. Wilson, Rebecca Fisher, and Tim R. McClanahan

Subjects
Biomass (ecology), Herbivore, Ecology, Insular biogeography, Coral reef fish, Aquatic Science, Fishery, Geography, Habitat, Marine protected area, Fisheries management, Ecology, Evolution, Behavior and Systematics, Global biodiversity
Abstract

The hypothesis that the history of management compliance (strong versus variable), closure size (0.3 to 28 km2), closure age (2 to 39 yr), and habitat/geographic variables influenced total fish biomass, the number of species, and the ratio of herbivores to carnivores in no-take areas was tested. Twenty existing closures across 6 countries in the western Indian Ocean were sampled during the same time period (2004 to 2007). Geographic location and closure attributes were weak to moderate predictors of these coral reef fish community variables for analyses of all closures. Strong interactions between fish community variables and levels of compliance indicated that high compliance sites largely drove the closure–fish community relationships. Variable or weak compliance and closures

Published
2009

49. Assessing the stocks of the primary snappers caught in Northeastern Brazilian reef systems. 1: Traditional modelling approaches

Author

Thierry Frédou, Yves Letourneur, and Beatrice Padovani Ferreira

Subjects
Fishery, Geography, Stock assessment, Virtual population analysis, biology, Coral reef fish, Lutjanidae, Fishing, Artisanal fishing, Aquatic Science, biology.organism_classification, Discards, Lutjanus
Abstract

Traditional stock assessment models were used to describe the current status of Lutjanus analis , L. chrysurus , L. jocu , L. synagris , and L. vivanus stocks off the coast of Northeast Brazil. The yield per recruit model, cohort analysis models (length-based cohort analysis (LCA), pseudo-cohort virtual population analysis (VPA), and real cohort VPA), and Thompson and Bell predictive model were used. The results showed LCA accumulates biases from pseudo-cohort VPA along with a high degree of sensitivity of growth parameters, whose determination is problematic and may not be adequate for many other reef species. Although the real cohort VPA based on short time series may also be limited, this method was determined to be the most appropriate within the traditional methods applied for the assessment of reef fish. However, the VPA model heavily depends on the accuracy of landing data and discards estimation and estimated natural mortality ( M ), so caution should be applied when using such models. The conservative fishing mortality index F 0.1 was found to be the most adapted index when the uncertainty of parameter estimation and model limitations were considered. Consequently, a drastic reduction of 80–90% of the current fishing effort is recommended. Despite the VPA and Thompson and Bell model limitations, these models can provide insight into species/fishery dynamics and can also be utilised to analyse the effects of changes in fishing level on catches. In addition, the trends presented in this study are confirmed in a companion paper using more complex models.

Published
2009

50. Assessing the stocks of the primary snappers caught in Northeastern Brazilian Reef Systems. 2-A multi-fleet age-structured approach

Author

Thierry Frédou, Yves Letourneur, and Beatrice Padovani Ferreira

Subjects
Stock assessment, geography.geographical_feature_category, biology, Ecology, Artisanal fishing, Aquatic Science, biology.organism_classification, Lutjanus, Lutjanus synagris, Fishery, Geography, Lutjanidae, Synagris, Reef, Stock (geology)
Abstract

This study investigates the exploitation of Lutjanus analis, Lutjanus chrysurus, Lutjanus jocu and Lutjanus synagris from multiple gear types in Northeast Brazil using models allowing for technological interactions. The spatial distribution of species and fleets have played an important role in the Northeastern Brazilian artisanal fishery. The results of a predictive model by Thompson and Bell, along with a catch-at-age model, clearly showed that different fleets had distinct effects on snapper stocks. The fishery mortality ( F ) from small-scale fleets (‘Jangada’ and ‘Paquete’) was higher for coastal species such as L. synagris that are typically found in these areas . Conversely, L. jocu , that inhabits deeper waters, was most affected by motorised and sailing boats. Snappers were exploited differently at each of their life history stages. ‘Paquetes’ mainly exploited juveniles, whereas boats caught larger individuals farther from the coast. As a consequence, effort control through fleet regulation seems to be much more applicable in a tropical context than traditional catch control. Further modelling studies and management options relevant to the Northeast Brazil fishery are discussed.

Published
2009

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