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Auteur Dubois, M.; Rossi, V.; Ser-Giacomi, E.; Arnaud-Haond, S.; Lopez, C.; Hernandez-Garcia, E.
Titre (up) Linking basin-scale connectivity, oceanography and population dynamics for the conservation and management of marine ecosystems Type Article scientifique
Année 2016 Publication Global Ecology and Biogeography Revue Abrégée Glob. Ecol. Biogeogr.
Volume 25 Numéro 5 Pages 503-515
Mots-Clés coral-reef fish; dispersal; genetic-structure; Larval dispersal; local retention; local retention; marine connectivity; marine ecosystems; marine protected areas; mediterranean littoral fishes; Mediterranean Sea; metapopulation; pelagic larval duration; population dynamics; Population Genetics; protected-area design; sea; self-recruitment; sink dynamics; source
Résumé AimAssessing the spatial structure and dynamics of marine populations is still a major challenge in ecology. The need to manage marine resources from ecosystem and large-scale perspectives is recognized, but our partial understanding of oceanic connectivity limits the implementation of globally pertinent conservation planning. Based on a biophysical model for the entire Mediterranean Sea, this study takes an ecosystem approach to connectivity and provides a systematic characterization of broad-scale larval dispersal patterns. It builds on our knowledge of population dynamics and discusses the ecological and management implications. LocationThe semi-enclosed Mediterranean Sea and its marine ecosystems are used as a case study to investigate broad-scale connectivity patterns and to relate them to oceanography and population dynamics. MethodsA flow network is constructed by evenly subdividing the basin into sub-regions which are interconnected through the transport of larvae by ocean currents. It allows for the computation of various connectivity metrics required to evaluate larval retention and exchange. ResultsOur basin-scale model predicts that retention processes are weak in the open ocean while they are significant in the coastal ocean and are favoured along certain coastlines due to specific oceanographic features. Moreover, we show that wind-driven divergent (convergent, respectively) oceanic regions are systematically characterized by larval sources (sinks, respectively). Finally, although these connectivity metrics have often been studied separately in the literature, we demonstrate they are interrelated under particular conditions. Their integrated analysis facilitates the appraisal of population dynamics, informing both genetic and demographic connectivities. Main conclusionsThis modelling framework helps ecologists and geneticists to formulate improved hypotheses of population structures and gene flow patterns and to design their sampling strategy accordingly. It is also useful in the implementation and assessment of future protection strategies, such as coastal and offshore marine reserves, by accounting for large-scale dispersal patterns, a missing component of current ecosystem management.
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ISSN 1466-822x ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1655
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Auteur D'agata, S.; Mouillot, D.; Wantiez, L.; Friedlander, A.M.; Kulbicki, M.; Vigliola, L.
Titre (up) Marine reserves lag behind wilderness in the conservation of key functional roles Type Article scientifique
Année 2016 Publication Revue Abrégée Nat. Commun.
Volume 7 Numéro Pages 12000
Mots-Clés biodiversity; coral-reef fishes; diversity indexes; ecosystem; new-caledonia; population-density; protected areas; species richness; visual-census; vulnerability
Résumé Although marine reserves represent one of the most effective management responses to human impacts, their capacity to sustain the same diversity of species, functional roles and biomass of reef fishes as wilderness areas remains questionable, in particular in regions with deep and long-lasting human footprints. Here we show that fish functional diversity and biomass of top predators are significantly higher on coral reefs located at more than 20 h travel time from the main market compared with even the oldest (38 years old), largest (17,500 ha) and most restrictive (no entry) marine reserve in New Caledonia (South-Western Pacific). We further demonstrate that wilderness areas support unique ecological values with no equivalency as one gets closer to humans, even in large and well-managed marine reserves. Wilderness areas may therefore serve as benchmarks for management effectiveness and act as the last refuges for the most vulnerable functional roles.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 2041-1723 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ alain.herve @ collection 1625
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Auteur Annasawmy, P.; Ternon, J.F.; Marsac, F.; Cherel, Y.; Behagle, N.; Roudaut, G.; Lebourges-Dhaussy, A.; Demarcq, H.; Moloney, C.L.; Jaquemet, S.; Menard, F.
Titre (up) Micronekton diel migration, community composition and trophic position within two biogeochemical provinces of the South West Indian Ocean: Insight from acoustics and stable isotopes Type Article scientifique
Année 2018 Publication Revue Abrégée Deep-Sea Res. Part I-Oceanogr. Res. Pap.
Volume 138 Numéro Pages 85-97
Mots-Clés Diel vertical migration; East African Coastal province; equatorial atlantic; feeding ecology; Indian South Subtropical Gyre; large pelagic fishes; mesopelagic fishes; mesoscale features; Micronekton; mozambique channel; myctophid fishes; north-atlantic ocean; respiratory carbon; Trophic level; vertical-distribution
Résumé Spatial distribution, community composition and trophic roles of micronekton (crustaceans, fishes and squids) were investigated in the Indian South Subtropical Gyre (ISSG) province and the East African Coastal province (EAFR), by combining acoustic surveys, mid-water trawls and stable isotope analyses from scientific cruises conducted in 2009 and 2010. Mesopelagic micronekton performed diel vertical migrations in both provinces, from deep (400-740 m) to surface (0-200 m) layers at dusk and in the opposite direction at dawn, with some species migrating below 740 m. The EAFR province was more dynamic than the oligotrophic ISSG province, with enhanced eddy activity and enhanced yearly productivity. The active enrichment mechanisms in the EAFR, in terms of available primary production, led to high micronekton acoustic density (as a proxy of micronekton abundance) and large micronekton weight and abundance estimates from trawl data. Particulate organic matter in the EAFR exhibited greater enrichment in C-13 and N-15 compared to the ISSG and, consequently, tissues of selected micronekton organisms in the EAFR were more enriched in N-15 (higher delta N-15 values). In both provinces, micronekton encompassed a wide range of isotopic niches, with large overlaps between species. Micronekton and swordfish in the EAFR had an overlapping range of delta N-15 values, contrasting with the ISSG province where swordfish were two trophic levels higher than the sampled micronekton. Our results provide some evidence that the combined action of riverine input and the dynamics of eddies might influence productivity in the EAFR, and hence the abundance of micronekton and the enrichment of tissues in N-15, compared to the oligotrophic ISSG province.
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Volume de collection Numéro de collection Edition
ISSN 0967-0637 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2431
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Auteur Annasawmy, P.; Ternon, J.-F.; Cotel, P.; Cherel, Y.; Romanov, E.; Roudaut, G.; Lebourges-Dhaussy, A.; Menard, F.; Marsac, F.
Titre (up) Micronekton distributions and assemblages at two shallow seamounts of the south-western Indian Ocean: Insights from acoustics and mesopelagic trawl data Type Article scientifique
Année 2019 Publication Revue Abrégée Prog. Oceanogr.
Volume 178 Numéro Pages 102161
Mots-Clés Acoustics; deep-scattering layer; diel migration; fish aggregations; mesoscale features; Micronekton; mozambique channel; myctophid fishes; pelagic communities; Seamount; Seamount-associated fauna; South-western Indian Ocean; species identification; target strength; vertical-distribution
Résumé Micronekton distributions and assemblages were investigated at two shallow seamounts of the south-western Indian Ocean using a combination of trawl data and a multi-frequency acoustic visualisation technique. La Pa rouse seamount (summit depth similar to 60 m) is located on the outskirts of the oligotrophic Indian South Subtropical Gyre (ISSG) province with weak mesoscale activities and low primary productivity all year round. The “MAD-Ridge” seamount (thus termed in this study; similar to 240 m) is located in the productive East African Coastal (EAFR) province with high mesoscale activities to the south of Madagascar. Higher micronekton species richness was recorded at MAD-Ridge compared to La Perouse. Resulting productivity at MAD-Ridge seamount was likely due to the action of mesoscale eddies advecting productivity and larvae from the Madagascar shelf rather than local dynamic processes such as Taylor column formation. Mean micronekton abundance/biomass, as estimated from mesopelagic trawl catches, were lower over the summit compared to the vicinity of the seamounts, due to net selectivity and catchability and depth gradient on micronekton assemblages. Mean acoustic densities in the night shallow scattering layer (SSL: 10-200 m) over the summit were not significantly different compared to the vicinity (within 14 nautical miles) of MAD-Ridge. At La Perouse and MAD-Ridge, the night and day SSL were dominated by common diel vertically migrant and non-migrant micronekton species respectively. While seamount-associated mesopelagic fishes such as Diaphus suborbitalis (La Perouse and MAD-Ridge) and Benthosema fibula= performed diel vertical migrations (DVM) along the seamounts' flanks, seamount-resident benthopelagic fishes, including Cookeolus japonicus (MAD-Ridge), were aggregated over MAD-Ridge summit. Before sunrise, mid-water migrants initiated their vertical migration from the intermediate to the deep scattering layer (DSL, La Perouse: 500-650 m; MAD-Ridge: 400-700 m) or deeper. During sunrise, the other taxa contributing to the night SSL exhibited a series of vertical migration events from the surface to the DSL or deeper until all migrants have reached the DSL before daytime. Possible mechanisms leading to the observed patterns in micronekton vertical and horizontal distributions are discussed. This study contributes to a better understanding of how seamounts influence the DVM, horizontal distribution and community composition of micronekton and seamount-associated/resident species at two poorly studied shallow topographic features in the south-western Indian Ocean.
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Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0079-6611 ISBN Médium
Région Expédition Conférence
Notes WOS:000496861900013 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2666
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Auteur Su, G.; Villeger, S.; Brosse, S.
Titre (up) Morphological sorting of introduced freshwater fish species within and between donor realms Type Article scientifique
Année 2020 Publication Revue Abrégée Glob. Ecol. Biogeogr.
Volume Numéro Pages
Mots-Clés biogeographic realms; body-size; ecology; establishment; exported species; functional diversity; hydropower; imputation; invasion steps; invasion success; morphological traits; morphospace; nonnative fishes; rivers; trade; traits; translocated species
Résumé Aim: To determine which morphological characteristics make a fish species a good candidate for introduction and establishment, we tested whether (a) introduced species differ in morphology from non-introduced species (species only existing in native areas and not introduced to new areas) in each donor assemblage (biogeographic realm fauna); (b) within the introduced species, the morphology of established species (self-sustaining introduced species) differs from that of the non-established species; (c) within the established species, those exported out of their native realm have more extreme morphological traits than those translocated within their native realm. Major taxa studied: Freshwater fish. Location: Global. Time period: 1960s-2010s. Methods: We used a global database of freshwater fishes from the six realms. Ten morphological traits were measured on 9,150 species. Principal component analysis was conducted to combine the 10 traits into a multidimensional morphospace. We used permutational multivariate analysis of variance (PERMANOVA) and permutational analysis for the multivariate homogeneity of dispersions (PERMDISP2) to compare the distribution of species groups in the morphospace and Kolmogorov-Smirnov tests to compare their distributions on principal component (PC) axes. Results: The morphology of introduced species differed from that of non-introduced species in all the six biogeographic realms. Among introduced species, established species had more extreme morphological traits than non-established species in most realms. Among established species, exported species had more extreme morphological traits than translocated species. Main conclusions: Morphological differences between introduced and nonintroduced species rely on an anthropogenic trait selection for fisheries and angling, leading to the preference for the introduction of predators with large and laterally compressed bodies. Established introduced species represent a small subset of introduced species morphologies, with these species having more extreme morphological traits, probably making them more efficient in particular habitats than their non-established counterparts. This was particularly marked for fish morphologies adapted to lentic waters. Such a trend was apparent for exported species, which have more extreme traits than translocated species.
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Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1466-822x ISBN Médium
Région Expédition Conférence
Notes WOS:000512276700001 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2740
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