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Auteur (up) Ecoutin, J.-M.; Simier, M.; Albaret, J.-J.; Laë, R.; Raffray, J.; Sadio, O.; Tito de Morais, L.
Titre Ecological field experiment of short-term effects of fishing ban on fish assemblages in a tropical estuarine MPA Type Article scientifique
Année 2014 Publication Revue Abrégée Ocean & Coastal Management
Volume 100 Numéro Pages 74-85
Mots-Clés
Résumé Marine Protected Areas (MPAs), in addition to their important role in the conservation of critical habitats and vulnerable species, are now also used in a context of ecosystem-based fisheries management. The aim of this study was to assess the observed changes in the fish population structure in the years following a fishing ban. The experiment took place in the Bamboung bolong, a small bay in the Sine Saloum estuary in Senegal, West Africa. The protection of this zone was undertaken with local fishermen support, and a formal MPA was created in 2004. The survey of the fish assemblages was initiated in 2003, the year before the fishing ban, and went on until 2007, with 12 sampling sites being monitored three times per year. In this paper, we describe and analyze the evolution of the fish assemblage during this five years' experimental period. Some changes have been highlighted on which the effect of the fishing ban was shown. After the fishing ban, an increase of total biomass and of maximal fish length has been registered. In the same time, the number of species has increased and the percentage of large and/or iconic species targeted by fishing has also increased. The community structure has been modified, with more small fish, more big fish (new large species and more large individuals in the original species) and fewer medium sized fish. The contribution of marine affinity species has increased in depend of the estuarine part of the assemblage. Finally, the trophic structure has been modified with an overall increase of the mean trophic level, resulting from an increase of the percentage of generalist or piscivorous predators and a sharp decrease of herbivorous and detritivorous low trophic level species. Marine predators which numbers and size were reduced by fisheries are again important components of the system. We argue that despite the intrinsic variability of the tropical estuarine environments, the introduction of a total ban on fishing in such estuarine zones can substantially improve the health status of the fish assemblage.
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ISSN 0964-5691 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1198
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Auteur (up) Elisabeth, N.H.; Caro, A.; Cesaire, T.; Mansot, J.-L.; Escalas, A.; Sylvestre, M.-N.; Jean-Louis, P.; Gros, O.
Titre Comparative modifications in bacterial gill-endosymbiotic populations of the two bivalves Codakia orbiculata and Lucina pensylvanica during bacterial loss and reacquisition Type Article scientifique
Année 2014 Publication Revue Abrégée FEMS microbiology ecology
Volume 89 Numéro 3 Pages
Mots-Clés Index Medicus; Lucinidae; cell size; endosymbiotic population; genomic content; starvation; sulphur content
Résumé Until now, the culture of sulphur-oxidizing bacterial symbionts associated with marine invertebrates remains impossible. Therefore, few studies focused on symbiont's physiology under stress conditions. In this study, we carried out a comparative experiment based on two different species of lucinid bivalves (Codakia orbiculata and Lucina pensylvanica) under comparable stress factors. The bivalves were starved for 6months in sulphide-free filtered seawater. For C.orbiculata only, starved individuals were then put back to the field, in natural sediment. We used in situ hybridization, flow cytometry and X-ray fluorescence to characterize the symbiont population hosted in the gills of both species. In L.pensylvanica, no decrease in symbiont abundance was observed throughout the starvation experiment, whereas elemental sulphur slowly decreased to zero after 3months of starvation. Conversely, in C.orbiculata, symbiont abundance within bacteriocytes decreased rapidly and sulphur from symbionts disappeared during the first weeks of the experiment. The modifications of the cellular characteristics (SSC – relative cell size and FL1 – genomic content) of the symbiotic populations along starvation were not comparable between species. Return to the sediment of starved C.orbiculata individuals led to a rapid (2-4weeks) recovery of symbiotic cellular characteristics, comparable with unstressed symbionts. These results suggest that endosymbiotic population regulation is host-species-dependent in lucinids. 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1574-6941 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 481
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Auteur (up) Elleouet, J.; Albouy, C.; Ben Rais Lasram, F.; Mouillot, D.; Leprieur, F.
Titre A trait-based approach for assessing and mapping niche overlap between native and exotic species: the Mediterranean coastal fish fauna as a case study Type Article scientifique
Année 2014 Publication Revue Abrégée Diversity and Distributions
Volume 20 Numéro 11 Pages 1333-1344
Mots-Clés Biological invasions; coastal fishes; endemic species; exotic species; functional traits; Mediterranean Sea; niche overlap
Résumé Aim We propose a trait-based approach for assessing and mapping potential niche overlap between native and exotic species at large spatial scales. Location The Mediterranean Sea. Methods We developed two complementary indices based on ecological, biological and ecomorphological similarities between native and exotic species. The first index (FNNr) allows identifying areas where native species are the most at risk in terms of potential ecological interactions with exotic species. The second index (FGO) is species-specific and allows identifying native species that display the broadest functional niche overlap and range overlap with exotic species. We illustrated our approach using the Mediterranean coastal fish fauna as a case study. Results We found that endemic and exotic fishes had a similar global functional niche at the Mediterranean scale, that is, they filled the same functional space defined by trait axes. FNNr hotspots were found to be moderately congruent with exotic species richness hotspots. Higher values of FNNr were observed along the coasts of the Levantine Sea. The computation of the FGO index showed that the geographical range of a given endemic species overlapped in average with 52 exotic species. Species showing the highest FGO values displayed localized and/or fragmented distributions in the eastern Mediterranean basin. Main conclusions Our findings suggest that the number of exotic species alone cannot be used as a broad-scale indicator of potential impact because this metric does not account for functional relatedness between native and exotic species. The trait-based indices developed in this study can be used for other taxa in both aquatic and terrestrial ecosystems and should help environmental managers to set up local-scale studies on areas where the potential impact of exotic species on native biodiversity is the highest.
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ISSN 1472-4642 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1165
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Auteur (up) Espinoza, P.; Bertrand, A.
Titre Ontogenetic and spatiotemporal variability in anchoveta Engraulis ringens diet off Peru Type Article scientifique
Année 2014 Publication Revue Abrégée Journal of Fish Biology
Volume 84 Numéro 2 Pages 422-435
Mots-Clés euphausiids; Humboldt Current system; oxygen; Peruvian anchovy; spatiotemporal variability; trophic ecology
Résumé In this study, historical data available since 1954 were used to get new insight to ontogenetic and spatiotemporal variability in Peruvian anchovy or anchoveta Engraulis ringens diet. Whatever the period, E. ringens foraged mainly on macrozooplankton and the importance of euphausiids in E. ringens diet appears directly related to euphausiids abundance. This bottom-up effect is also observed at smaller scale because the euphausiids fraction increased with E. ringens total length and euphausiids accessibility. Selecting the largest prey, the euphausiids, provides an energetic advantage for E. ringens in its ecosystem where oxygen depletion imposes strong metabolic constraints on pelagic fishes. This study illustrates the plasticity of E. ringens that allows it to cope with its highly variable environment.
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Volume de collection Numéro de collection Edition
ISSN 0022-1112 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 358
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Auteur (up) Fablet, R.; Chaigneau, A.; Bertrand, S.
Titre Multiscale analysis of geometric planar deformations : application to wild animal electronic tracking and satellite ocean observation data Type Article scientifique
Année 2014 Publication Revue Abrégée Ieee Transactions on Geoscience and Remote Sensing
Volume 52 Numéro 6 Pages 3627-3636
Mots-Clés Animal movements; geophysical fields; multiscale geometry; planar curve; trajectory analysis; wavelet analysis
Résumé The development of animal tracking technologies (including GPS and ARGOS satellite systems) and the increasing resolution of remote-sensing observations call for tools extracting and describing the geometric patterns along a track or within an image over a wide range of spatial scales. Whereas shape analysis has largely been addressed over the last decades, the multiscale analysis of the geometry of opened planar curves has received little attention. We here show that classical multiscale techniques cannot properly address this issue and propose an original wavelet-based scheme. To highlight the generic nature of our multiscale wavelet technique, we report applications to two different observation data sets, namely, wild animal movement paths recorded by electronic tags and satellite observations of sea-surface geophysical fields.
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ISSN 0196-2892 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 328
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