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Auteur Miller, M.J.; Bonhommeau, S.; Munk, P.; Castonguay, M.; Hanel, R.; McCleave, J.D. url  openurl
  Titre A century of research on the larval distributions of the Atlantic eels: a re-examination of the data Type Article scientifique
  Année 2014 Publication Revue Abrégée Biological Reviews  
  Volume Numéro Pages  
  Mots-Clés anguilla; freshwater eels; larval distribution; oceanic fronts.; Sargasso Sea; spawning area  
  Résumé The spawning areas of the Atlantic freshwater eels were discovered about a century ago by the Danish scientistJohannes Schmidt who after years of searching found newly hatched larvae of the European eel, Anguillaanguilla, and the American eel, Anguilla rostrata, in the southern Sargasso Sea. The discovery showed thatanguillid eels migrate thousands of kilometers to offshore spawning areas for reproduction, and that theirlarvae, called leptocephali, are transported equally long distances by ocean currents to their continentalrecruitment areas. The spawning sites were found to be related to oceanographic conditions several decadeslater by German and American surveys from 1979 to 1989 and by a Danish survey in 2007 and a Germansurvey in 2011. All these later surveys showed that spawning occurred within a restricted latitudinal range,between temperature fronts within the Subtropical Convergence Zone of the Sargasso Sea. New data andre-examinations of Schmidt’s data confirmed his original conclusions about the two species having someoverlap in spawning areas. Although there have been additional collections of leptocephali in various parts ofthe North Atlantic, and both otolith research and transport modelling studies have subsequently been carriedout, there is still a range of unresolved questions about the routes of larval transport and durations of migration.This paper reviews the history and basic findings of surveys for anguillid leptocephali in the North Atlantic andanalyses a new comprehensive database that includes 22612 A. anguilla and 9634 A. rostrata leptocephali, whichprovides a detailed view of the spatial and temporal distributions and size of the larvae across the Atlantic basinand in the Mediterranean Sea. The differences in distributions, maximum sizes, and growth rates of the twospecies of larvae are likely linked to the contrasting migration distances to their recruitment areas on eachside of the basin. Anguilla rostrata leptocephali originate from a more western spawning area, grow faster, andmetamorphose at smaller sizes of <70mm than the larvae of A. anguilla, which mostly are spawned further eastand can reach sizes of almost 90 mm. The larvae of A. rostrata spread west and northwest from the spawningarea as they grow larger, with some being present in the western Caribbean and eastern Gulf of Mexico. Larvaeof A. anguilla appear to be able to reach Europe by entering the Gulf Stream system or by being entrainedinto frontal countercurrents that transport them directly northeastward. The larval duration of A. anguillais suggested to be quite variable, but gaps in sampling effort prevent firm conclusions. Although knowledgeabout larval behaviour is lacking, some influences of directional swimming are implicated by the temporaldistributions of the largest larvae. Ocean–atmosphere changes have been hypothesized to affect the survivalof the larvae and cause reduced recruitment, so even after about a century following the discovery of theirspawning areas, mysteries still remain about the marine life histories of the Atlantic eels.  
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  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1464-7931 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1125  
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Auteur CORMON, X.; LOOTS, C.; VAZ, S.; VERMARD, Y.; MARCHAL, P. url  openurl
  Titre Spatial interactions between saithe (Pollachius virens) and hake (Merluccius merluccius) in the North Sea Type Article scientifique
  Année 2014 Publication Revue Abrégée Ices Journal Of Marine Science  
  Volume 71 Numéro 6 Pages 1342-1355  
  Mots-Clés biotic interactions; competition; Generalized linear models; Hake; North sea; overlap; predator-prey relationship; saithe; species distribution modelling  
  Résumé Spatial interactions between saithe (Pollachius virens) and hake (Merluccius merluccius) were investigated in the North Sea. Saithe is a well-established species in the North Sea, while occurrence of the less common hake has recently increased in the area. Spatial dynamics of these two species and their potential spatial interactions were explored using binomial generalized linear models (GLM) applied to the International Bottom Trawl Survey (IBTS) data from 1991 to 2012. Models included different types of variables: (i) abiotic variables including sediment types, temperature, and bathymetry; (ii) biotic variables including potential competitors and potential preys presence; and (iii) spatial variables. The models were reduced and used to predict and map probable habitats of saithe, hake but also, for the first time in the North Sea, the distribution of the spatial overlap between these two species. Changes in distribution patterns of these two species and of their overlap were also investigated by comparing species' presence and overlap probabilities predicted over an early (1991–1996) and a late period (2007–2012). The results show an increase in the probability over time of the overlap between saithe and hake along with an expansion towards the southwest and Scottish waters. These shifts follow trends observed in temperature data and might be indirectly induced by climate changes. Saithe, hake, and their overlap are positively influenced by potential preys and/or competitors, which confirms spatial co-occurrence of the species concerned and leads to the questions of predator–prey relationships and competition. Finally, the present study provides robust predictions concerning the spatial distribution of saithe, hake, and of their overlap in the North Sea, which may be of interest for fishery managers.  
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  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1054-3139 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1135  
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Auteur Meynard, C.N.; Leroy, B.; Kaplan, D.M. url  doi
openurl 
  Titre Testing methods in species distribution modelling using virtual species: what have we learnt and what are we missing? Type Article scientifique
  Année 2019 Publication Revue Abrégée Ecography  
  Volume 42 Numéro 12 Pages 2021-2036  
  Mots-Clés artificial species; environmental niche models; niche; simulations; species distribution modelling; virtual ecologist  
  Résumé Species distribution models (SDMs) have become one of the major predictive tools in ecology. However, multiple methodological choices are required during the modelling process, some of which may have a large impact on forecasting results. In this context, virtual species, i.e. the use of simulations involving a fictitious species for which we have perfect knowledge of its occurrence–environment relationships and other relevant characteristics, have become increasingly popular to test SDMs. This approach provides for a simple virtual ecologist framework under which to test model properties, as well as the effects of the different methodological choices, and allows teasing out the effects of targeted factors with great certainty. This simplification is therefore very useful in setting up modelling standards and best practice principles. As a result, numerous virtual species studies have been published over the last decade. The topics covered include differences in performance between statistical models, effects of sample size, choice of threshold values, methods to generate pseudo-absences for presence-only data, among many others. These simulations have therefore already made a great contribution to setting best modelling practices in SDMs. Recent software developments have greatly facilitated the simulation of virtual species, with at least three different packages published to that effect. However, the simulation procedure has not been homogeneous, which introduces some subtleties in the interpretation of results, as well as differences across simulation packages. Here we 1) review the main contributions of the virtual species approach in the SDM literature; 2) compare the major virtual species simulation approaches and software packages; and 3) propose a set of recommendations for best simulation practices in future virtual species studies in the context of SDMs.  
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  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1600-0587 ISBN Médium  
  Région Expédition Conférence  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2687  
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Auteur Stephenson, F.; Goetz, K.; Sharp, B.R.; Mouton, T.L.; Beets, F.L.; Roberts, J.; MacDiarmid, A.B.; Constantine, R.; Lundquist, C.J. url  doi
openurl 
  Titre Modelling the spatial distribution of cetaceans in New Zealand waters Type Article scientifique
  Année 2020 Publication Revue Abrégée Diversity and Distributions  
  Volume 26 Numéro 4 Pages 495-516  
  Mots-Clés boosted regression tree models; cetacean distribution; New Zealand; relative environmental suitability models; spatial management; species distribution models  
  Résumé Aim Cetaceans are inherently difficult to study due to their elusive, pelagic and often highly migratory nature. New Zealand waters are home to 50% of the world's cetacean species, but their spatial distributions are poorly known. Here, we model distributions of 30 cetacean taxa using an extensive at-sea sightings dataset (n > 14,000) and high-resolution (1 km2) environmental data layers. Location New Zealand's Exclusive Economic Zone (EEZ). Methods Two models were used to predict probability of species occurrence based on available sightings records. For taxa with <50 sightings (n = 15), Relative Environmental Suitability (RES), and for taxa with ≥50 sightings (n = 15), Boosted Regression Tree (BRT) models were used. Independently collected presence/absence data were used for further model evaluation for a subset of taxa. Results RES models for rarely sighted species showed reasonable fits to available sightings and stranding data based on literature and expert knowledge on the species' autecology. BRT models showed high predictive power for commonly sighted species (AUC: 0.79–0.99). Important variables for predicting the occurrence of cetacean taxa were temperature residuals, bathymetry, distance to the 500 m isobath, mixed layer depth and water turbidity. Cetacean distribution patterns varied from highly localised, nearshore (e.g., Hector's dolphin), to more ubiquitous (e.g., common dolphin) to primarily offshore species (e.g., blue whale). Cetacean richness based on stacked species occurrence layers illustrated patterns of fewer inshore taxa with localised richness hotspots, and higher offshore richness especially in locales of the Macquarie Ridge, Bounty Trough and Chatham Rise. Main conclusions Predicted spatial distributions fill a major knowledge gap towards informing future assessments and conservation planning for cetaceans in New Zealand's extensive EEZ. While sightings datasets were not spatially comprehensive for any taxa, these two best available approaches allow for predictive modelling of both more common, and of rarely sighted, cetacean species with limited available information.  
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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 1472-4642 ISBN Médium  
  Région Expédition Conférence  
  Notes WOS:000510589200001 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2692  
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Auteur Bouvy, M.; Got, P.; Domaizon, I.; Pagano, M.; Leboulanger, C.; Bouvier, C.; Carré, C.; Roques, C.; Dupuy, C. url  doi
openurl 
  Titre Plankton communities in the five Iles Eparses (Western Indian Ocean) considered to be pristine ecosystems Type Article scientifique
  Année 2016 Publication Revue Abrégée Acta Oecologica  
  Volume Numéro Pages 9-20  
  Mots-Clés Distribution; Enrichment experiment; Iles Eparses; Islands; Microorganisms; Mozambique Channel; Nutrient limitation  
  Résumé Coral reef environments are generally recognized as being the most threatened of marine ecosystems. However, it is extremely difficult to distinguish the effects of climate change from other forcing factors, mainly because it is difficult to study ecosystems that are isolated from human pressure. The five Iles Eparses (Scattered Islands) are located in the Western Indian Ocean (WIO) and can be considered to be “pristine” ecosystems not subject to anthropogenic pressure. This study characterized their plankton assemblages for the first time, by determining the abundances of microbial (virus, bacteria, heterotrophic protists and phytoplankton) and metazooplankton communities in various lagoon and ocean sites around each island. The Europa lagoon has extensive, productive mangrove forests, which have the highest nutrient concentrations (nitrogen forms, dissolved organic carbon) and whose microbial communities present a peculiar structure and functioning. By means of bioassay experiments, we observed that bacterial production and growth rates are higher in Europa than those reported for the other islands. Tromelin, which lies outside the Mozambique Channel, had the lowest biological productivity, nutrient concentrations, and bacterial growth rates. Multivariate analysis indicated that distinct microbial assemblages occur in association to varying nutrient concentrations. Molecular fingerprinting showed clear discrimination of the structure of the archaea, bacteria and eukaryotes community between the sites. Our results suggest that the geographical distance can influence the diversity of dominant microbial taxa in the WIO.  
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  Éditeur de collection Titre de collection Îles Éparses (French Scattered Islands, SW Indian Ocean) as reference ecosystems for environmental research. Titre de collection Abrégé  
  Volume de collection 72 Numéro de collection Edition  
  ISSN 1146-609x ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1494  
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