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Auteur MUTHS, D.; TESSIER, E.; BOURJEA, J.
Titre Genetic structure of the reef grouper Epinephelus merra in the West Indian Ocean appears congruent with biogeographic and oceanographic boundaries Type Article scientifique
Année 2015 Publication Revue Abrégée Marine Ecology-an Evolutionary Perspective
Volume 36 Numéro 3 Pages 447-461
Mots-Clés Cytochrome b; marine connectivity; microsatellite; reef fish; West Indian Ocean
Résumé The reef fauna connectivity of the West Indian Ocean (WIO) is one of the least studied globally. Here we use genetic analyses of the grouper Epinephelus merra (Bloch 1793) to determine patterns of connectivity and to identify barriers to dispersal in this WIO marine area. Phylogeographic and population-level analyses were conducted on cytochrome b sequences and microsatellites (13 loci) from 557 individuals sampled in 15 localities distributed across the West Indian Ocean. Additional samples from the Pacific Ocean were used to benchmark the WIO population structure. The high level of divergence revealed between Indian and Pacific localities (of about 4.5% in sequences) might be the signature of the major tectonic and climatic changes operating at the Plio-Pleistocene transition, congruently with numerous examples of Indo-Pacific speciation. In comparison, the E. merra sequences from the Indian Ocean constitute a monophyletic clade with a low average genetic distance (d < 0.5%). However both genetic markers indicated some structure within this ocean. The main structure revealed was the isolation of the Maldives from the WIO localities (a different group signature identified by clustering analysis, great values of differentiation). Both marker types reveal further significant structure within the WIO, mainly the isolation of the Mascarene Islands (significant AMOVA and isolation-by-distance patterns) and some patchy structure between the northernmost localities and within the Mozambique Channel. The WIO genetic structure of E. merra appeared congruent with main biogeographic boundaries and oceanographic currents.
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ISSN 0173-9565 ISBN (up) Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1436
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Auteur David, C.; Vaz, S.; Loots, C.; Antajan, E.; van der Molen, J.; Travers-Trolet, M.
Titre Understanding winter distribution and transport pathways of the invasive ctenophore Mnemiopsis leidyi in the North Sea: coupling habitat and dispersal modelling approaches Type Article scientifique
Année 2015 Publication Revue Abrégée Biol. Invasions
Volume 17 Numéro 9 Pages 2605-2619
Mots-Clés a. agassiz; anchoa-mitchilli; black-sea; caspian sea; fish; Habitat modelling; Jellyfish; Mnemiopsis leidyi; narragansett bay; North Sea; Overwinter refuges; Particle tracking; population connectivity; Predation; rhode-island
Résumé The invasive ctenophore Mnemiopsis leidyi has been reported in various coastal locations in the southern North Sea in the past years. Since 2009, International Bottom Trawl Surveys have recorded this species each winter in open waters. As this species, well-known for its dramatic disturbance of ecosystems, was expected not to be able to overwinter offshore it is crucial to understand its distribution dynamics. Two modelling methods, a quantile regression and a particle tracking model, were used (1) to identify habitats where the invasive ctenophore M. leidyi could survive the North Sea cold winters and (2) to investigate the dispersal of individuals between these different habitats, emphasizing favorable areas where sustainable populations could have been established. Temperature was found to be the crucial factor controlling the winter distribution of M. leidyi in the North Sea. High abundance predictions in winter were associated with low values of temperature, which characterise south-eastern coastal areas and estuaries influenced by riverine runoff. A retention-based M. leidyi population was indicated along the northern Dutch coast and German Bight and a transport-based population offshore from the western Danish coast. Individuals found in the open waters were transported from southern coasts of the North Sea, thus the open water population densities depend on the flux of offspring from these areas. This study provides the first estimates of the overwinter areas of this invasive species over the cold winters in the North Sea. Based on the agreement of habitat and dispersal model results, we conclude that M. leidyi has become established along south-eastern coasts of the North Sea where the environment conditions allows overwintering and it can be retained for later blooms.
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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 1387-3547 ISBN (up) Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1457
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Auteur Metcalfe, K.; Vaughan, G.; Vaz, S.; Smith, R.J.
Titre Spatial, socio-economic, and ecological implications of incorporating minimum size constraints in marine protected area network design Type Article scientifique
Année 2015 Publication Revue Abrégée Conservation Biology
Volume 29 Numéro 6 Pages 1615-1625
Mots-Clés conectividad; Connectivity; derrame y exportación; Marxan; MinPatch; planeación sistemática de la conservación; priorización de la conservación espacial; spatial conservation prioritization; spill-over and export; systematic conservation planning; viabilidad; viability
Résumé Marine protected areas (MPAs) are the cornerstone of most marine conservation strategies, but the effectiveness of each one partly depends on its size and distance to other MPAs in a network. Despite this, current recommendations on ideal MPA size and spacing vary widely, and data are lacking on how these constraints might influence the overall spatial characteristics, socio-economic impacts, and connectivity of the resultant MPA networks. To address this problem, we tested the impact of applying different MPA size constraints in English waters. We used the Marxan spatial prioritization software to identify a network of MPAs that met conservation feature targets, whilst minimizing impacts on fisheries; modified the Marxan outputs with the MinPatch software to ensure each MPA met a minimum size; and used existing data on the dispersal distances of a range of species found in English waters to investigate the likely impacts of such spatial constraints on the region's biodiversity. Increasing MPA size had little effect on total network area or the location of priority areas, but as MPA size increased, fishing opportunity cost to stakeholders increased. In addition, as MPA size increased, the number of closely connected sets of MPAs in networks and the average distance between neighboring MPAs decreased, which consequently increased the proportion of the planning region that was isolated from all MPAs. These results suggest networks containing large MPAs would be more viable for the majority of the region's species that have small dispersal distances, but dispersal between MPA sets and spill-over of individuals into unprotected areas would be reduced. These findings highlight the importance of testing the impact of applying different MPA size constraints because there are clear trade-offs that result from the interaction of size, number, and distribution of MPAs in a network.
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Langue en Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1523-1739 ISBN (up) Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1458
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Auteur Lett, C.; Barrier, N.; Ourmières, Y.; Petit, C.; Labonne, M.; Bourjea, J.; Darnaude, A.M.
Titre Modeling larval dispersal for the gilthead seabream in the northwestern Mediterranean Sea Type Article scientifique
Année 2019 Publication Revue Abrégée Marine Environmental Research
Volume Numéro Pages 104781
Mots-Clés Biophysical model; Connectivity; Fish; Gulf of Lions; Larvae; Models-hydrodynamic; Otolith
Résumé To investigate dispersal and connectivity between spawning and lagoon nursery habitats of the gilthead seabream, Sparus aurata, in the Gulf of Lions (northwestern Mediterranean Sea), we modeled the potential transport of the species’ larvae between its supposed main spawning site in the region (the Planier Island) and two of its main local nursery areas (the coastal lagoons of Thau and Salses-Leucate). Passive larval drift simulations using a dispersal biophysical model showed a large variability in the possible trajectories from spawning to nursery areas and in the predicted ages for larvae arrival on the two nursery sites. The most common ages at arrival obtained in the simulations (20–60 days) are broadly consistent with previous modeling studies but contrast with the actual ages of the S. aurata post-larvae collected in 2016 and 2017 at time of the lagoon entrances (60–90 days, from otolith readings). The period between 25 and 70 days being critical for gilthead seabream larvae to acquire sufficient swimming, osmoregulatory, and olfactory abilities to enter coastal lagoons, we argue that ontogenic development plays a crucial role in the transport and local retention of S. aurata larvae in the studied region, explaining the discrepancy between simulation results and observed data.
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Editeur Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0141-1136 ISBN (up) Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2613
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Auteur Dalleau, M.; Kramer-Schadt, S.; Gangat, Y.; Bourjea, J.; Lajoie, G.; Grimm, V.
Titre Modeling the emergence of migratory corridors and foraging hot spots of the green sea turtle Type Article scientifique
Année 2019 Publication Revue Abrégée Ecol. Evol.
Volume Numéro Pages
Mots-Clés aldabra atoll; chelonia-mydas; connectivity; corridors; individual-based model; leatherback turtles; marine turtles; migration; movement; penghu archipelago; population-dynamics; remigration intervals; satellite-tracking; sea turtle; wan-an island
Résumé Environmental factors shape the spatial distribution and dynamics of populations. Understanding how these factors interact with movement behavior is critical for efficient conservation, in particular for migratory species. Adult female green sea turtles, Chelonia mydas, migrate between foraging and nesting sites that are generally separated by thousands of kilometers. As an emblematic endangered species, green turtles have been intensively studied, with a focus on nesting, migration, and foraging. Nevertheless, few attempts integrated these behaviors and their trade-offs by considering the spatial configurations of foraging and nesting grounds as well as environmental heterogeneity like oceanic currents and food distribution. We developed an individual-based model to investigate the impact of local environmental conditions on emerging migratory corridors and reproductive output and to thereby identify conservation priority sites. The model integrates movement, nesting, and foraging behavior. Despite being largely conceptual, the model captured realistic movement patterns which confirm field studies. The spatial distribution of migratory corridors and foraging hot spots was mostly constrained by features of the regional landscape, such as nesting site locations, distribution of feeding patches, and oceanic currents. These constraints also explained the mixing patterns in regional forager communities. By implementing alternative decision strategies of the turtles, we found that foraging site fidelity and nesting investment, two characteristics of green turtles' biology, are favorable strategies under unpredictable environmental conditions affecting their habitats. Based on our results, we propose specific guidelines for the regional conservation of green turtles as well as future research suggestions advancing spatial ecology of sea turtles. Being implemented in an easy to learn open-source software, our model can coevolve with the collection and analysis of new data on energy budget and movement into a generic tool for sea turtle research and conservation. Our modeling approach could also be useful for supporting the conservation of other migratory marine animals.
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Auteur institutionnel Thèse
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 2045-7758 ISBN (up) Médium
Région Expédition Conférence
Notes WOS:000481747800001 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2621
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