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Auteur van der Geest, M.; van der Lely, J.A.C.; van Gils, J.A.; Piersma, T.; Lok, T. doi  openurl
  Titre Density-dependent growth of bivalves dominating the intertidal zone of Banc d'Arguin, Mauritania: importance of feeding mode, habitat and season Type Article scientifique
  Année 2019 Publication Revue Abrégée Mar. Ecol.-Prog. Ser.  
  Volume (down) 610 Numéro Pages 51-63  
  Mots-Clés biomass; Carrying capacity; Chemosymbiosis; competition; Density dependence; dynamics; ecosystem; Environmental heterogeneity; Feeding guild; flats; populations; seagrass; Seagrass; sediment; site; Soft-sediment habitat; variability  
  Résumé Accurate predictions of population dynamics require an understanding of the ways by which environmental conditions and species-specific traits affect the magnitude of density dependence. Here, we evaluated the potential impact of season and habitat (characterized by sediment grain size and seagrass biomass) on the magnitude of density dependence in shell growth of 3 infaunal bivalve species dominating the tropical intertidal benthic communities of Banc d'Arguin, Mauritania. Two of our focal species were filter feeders (Senilia senilis and Pelecyora isocardia) and one was a facultative mixotroph (Loripes orbiculatus), mainly relying on organic carbon provided by sulphide-oxidizing endosymbiotic gill-bacteria (i.e. chemosymbiotic). Distinguishing 2 seasons, winter and summer, we manipulated local bivalve densities across habitats (from bare sandy sediments to seagrass-covered mud). In situ growth of individually tagged and relocated clams was measured and compared with those of tagged clams that were allocated to adjacent sites where local bivalve densities were doubled. Growth was negatively density-dependent in both winter and summer in P. isocardia and L. orbiculatus, the 2 species that mainly inhabit seagrass sediments, but not in S. senilis, usually found in bare sediments. As reproduction and survival rates are generally size-dependent in bivalves, our results suggest that in our tropical study system, the bivalve community of seagrass-covered sediments is more strongly regulated than that of adjacent bare sediments, regardless of species-specific feeding mode or season. We suggest that ecosystem engineering by seagrasses enhances environmental stability, which allows bivalve populations within tropical seagrass beds to stay close to carrying capacity.  
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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 0171-8630 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2593  
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Auteur Viricel, A.; Simon-Bouhet, B.; Ceyrac, L.; Dulau-Drouot, V.; Berggren, P.; Amir, O.A.; Jiddawi, N.S.; Mongin, P.; Kiszka, J.J. doi  openurl
  Titre Habitat availability and geographic isolation as potential drivers of population structure in an oceanic dolphin in the Southwest Indian Ocean Type Article scientifique
  Année 2016 Publication Revue Abrégée Mar. Biol.  
  Volume (down) 163 Numéro 10 Pages 219  
  Mots-Clés biologically meaningful; bottle-nosed dolphins; genetic differentiation; marine populations; megaptera-novaeangliae; microsatellite loci; mozambique channel; spinner dolphins; stenella-longirostris; tursiops-truncatus  
  Résumé Delphinid populations show highly variable patterns of genetic diversity and population structure. Previous studies indicate that habitat discontinuities and geographic isolation are major drivers of population division in cetaceans. Spinner dolphins (Stenella longirostris) are distributed in all tropical oceans, but they are particularly common around islands and atolls. This species occurs in shallow waters at daytime to rest and socialise, and feeds on offshore mesopelagic prey overnight. Here, we investigated the genetic population structure of spinner dolphins in the Southwest Indian Ocean along a west-east geographic gradient, from eastern Africa to the Mascarene archipelago. We combined analyses of 12 microsatellite loci, mtDNA control region sequences, and sighting data to assess genetic differentiation and characterise habitat preferences of these populations. Significant genetic structure among the three sampled sites (Zanzibar, Mayotte and La Reunion) was observed using both types of molecular markers. Overall, our results indicate that geographic isolation and potentially other factors, such as shallow-water habitats to rest and socialise, may be important drivers of the genetic population structure of insular spinner dolphins in this region.  
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  Volume de collection Numéro de collection Edition  
  ISSN 0025-3162 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1700  
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Auteur Riou, V.; Ndiaye, A.; Budzinski, H.; Dugue, R.; Le Menach, K.; Combes, Y.; Bossus, M.; Durand, J.D.; Charmantier, G.; Lorin-Nebel, C. url  doi
openurl 
  Titre Impact of environmental DDT concentrations on gill adaptation to increased salinity in the tilapia Sarotherodon melanotheron Type Article scientifique
  Année 2012 Publication Revue Abrégée Comp. Biochem. Physiol. C-Toxicol. Pharmacol.  
  Volume (down) 156 Numéro 1 Pages 7-16  
  Mots-Clés DDTs; Na+/K+-ATPase; Osmoregulation; Rainbow trout; Teleost; cell responses; crucian carp; fish; gill; goldfish carassius-auratus; na-k-atpase; natural-populations; polychlorinated-biphenyls; salmo-gairdneri; water  
  Résumé Estuaries of tropical developing countries suffering from severe droughts induced by climate change are habitats to fish, which face drastic salinity variations and the contact with pollutants. The Western Africa tilapia Sarotherodon melanotheron is highly resistant to hypersalinity, but the effect of human-released xenobiotics on its adaptation is barely known. Controlled experiments were conducted to observe S. melanotheron gill adaptation to abrupt salinity variations in the presence of waterborne DDT, at concentrations detected in their natural habitat. The gills appeared as an important site of DDT conversion to DDD and/or depuration. A 12-days DDT exposure resulted in decreased gill epithelium thickness at all salinities (from fresh- to hypersaline-water), and the structure of gills from freshwater fish was particularly altered, relative to controls. No unbalance in tilapia blood osmolality was observed following DDT exposure, which however caused a decrease in branchial Na+-K+-ATPase (NKA) activity. Gill cellular NKA expression was reduced in salt-water, together with the expression of the CFTR chloride channel in hypersaline water. Although S. melanotheron seems very resistant (especially in seawater) to short-term waterborne DDT contamination, the resulting alterations of the gill tissue, cells and enzymes might affect longer term respiration, toxicant depuration and/or osmoregulation in highly fluctuating salinities. (C) 2012 Elsevier Inc. 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 1532-0456 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 649  
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Auteur Perry, R.I.; Cury, P.; Brander, K.; Jennings, S.; Mollmann, C.; Planque, B. url  doi
openurl 
  Titre Sensitivity of marine systems to climate and fishing: Concepts, issues and management responses Type Article scientifique
  Année 2010 Publication Revue Abrégée Journal of Marine Systems  
  Volume (down) 79 Numéro Pages 427-435  
  Mots-Clés change; climate; Communities; ecosystems; fisheries; Fishing; management; Populations; variability  
  Résumé Modern fisheries research and management must understand and take account of the interactions between climate and fishing, rather than try to disentangle their effects and address each separately. These interactions are significant drivers of change in exploited marine systems and have ramifications for ecosystems and those who depend on the services they provide. We discuss how fishing and climate forcing interact on individual fish, marine populations, marine communities, and ecosystems to bring these levels into states that are more sensitive to (i.e. more strongly related with) climate forcing. Fishing is unlikely to alter the sensitivities of individual finfish and invertebrates to climate forcing. It will remove individuals with specific characteristics from the gene pool, thereby affecting structure and function at higher levels of organisation. Fishing leads to a loss of older age classes, spatial contraction, loss of sub-units, and alteration of life history traits in populations, making them more sensitive to climate variability at interannual to interdecadal scales. Fishing reduces the mean size of individuals and mean trophic level of communities, decreasing their turnover time leading them to track environmental variability more closely. Marine ecosystems under intense exploitation evolve towards stronger bottom-up control and greater sensitivity to climate forcing. Because climate change occurs slowly, its effects are not likely to have immediate impacts on marine systems but will be manifest as the accumulation of the interactions between fishing and climate variability – unless threshold limits are exceeded. Marine resource managers need to develop approaches which maintain the resilience of individuals, populations, communities and ecosystems to the combined and interacting effects of climate and fishing. Overall, a less-heavily fished marine system, and one which shifts the focus from individual species to functional groups and fish communities, is likely to provide more stable catches with climate variability and change than would a heavily fished system. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.  
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  ISSN 0924-7963 ISBN Médium  
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  Numéro d'Appel LL @ pixluser @ collection 95  
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Auteur Van Beveren, E.; Fromentin, J.-M.; Rouyer, T.; Bonhommeau, S.; Brosset, P.; Saraux, C. doi  openurl
  Titre The fisheries history of small pelagics in the Northern Mediterranean Type Article scientifique
  Année 2016 Publication Revue Abrégée ICES J. Mar. Sci.  
  Volume (down) 73 Numéro 6 Pages 1474-1484  
  Mots-Clés age; anchovy; atlantic; dynamics; fish; fish landings; fluctuations; Gulf of Lions; historical time series; landings; mackerel; multidecadal oscillation; populations; Sardine; variability  
  Résumé Since 2007, the biomass of sardine and anchovy in the NW Mediterranean has remained persistently low, whereas the biomass of the commercially low-valued sprat has exploded. Also, simultaneous decreases in condition, size, and/or age of these populations were observed. Altogether, this resulted in a drop in landings of small pelagics. To understand the amplitude of these events and to provide a baseline scenario against which current changes can be compared, we compiled exceptionally long landing series (1865-2013) of sardine, anchovy, and mackerel for different subregions of the southern French coast. We characterized the fluctuations of these landings and compared these with environmental drivers (sea surface temperature, Rhone river discharge, North Atlantic Oscillation, Western Mediterranean Oscillation-WeMO, and Atlantic Multidecadal Oscillation-AMO), using different time-series analyses. We also collated historical data to infer qualitative changes in fishing effort over time. A fishing effort related increase in landings was observed around 1962 for all three species, although current sardine landings have dropped below levels observed before this period. Sardine and anchovy landings were, respectively, positively and negatively related to the AMO index and anchovy landings were also positively related to the WeMO. We finished by discussing the potential role of the environmental variables and fishing on long-term fishery landings trends.  
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  Langue English Langue du Résumé Titre Original  
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  Volume de collection Numéro de collection Edition  
  ISSN 1054-3139 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1652  
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