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Auteur Boavida, J.; Assis, J.; Silva, I.; Serrao, E.A. doi  openurl
  Titre Overlooked habitat of a vulnerable gorgonian revealed in the Mediterranean and Eastern Atlantic by ecological niche modelling Type Article scientifique
  Année 2016 Publication Revue Abrégée Sci Rep  
  Volume 6 Numéro Pages 36460  
  Mots-Clés climate-change; marine ecosystems; octocorals; paramuricea-clavata; prediction; sea; species distribution models; suitability; temperature; validation  
  Résumé Factors shaping the distribution of mesophotic octocorals (30-200 m depth) remain poorly understood, potentially leaving overlooked coral areas, particularly near their bathymetric and geographic distributional limits. Yet, detailed knowledge about habitat requirements is crucial for conservation of sensitive gorgonians. Here we use Ecological Niche Modelling (ENM) relating thirteen environmental predictors and a highly comprehensive presence dataset, enhanced by SCUBA diving surveys, to investigate the suitable habitat of an important structuring species, Paramuricea clavata, throughout its distribution (Mediterranean and adjacent Atlantic). Models showed that temperature (11.5-25.5 degrees C) and slope are the most important predictors carving the niche of P. clavata. Prediction throughout the full distribution (TSS 0.9) included known locations of P. clavata alongside with previously unknown or unreported sites along the coast of Portugal and Africa, including seamounts. These predictions increase the understanding of the potential distribution for the northern Mediterranean and indicate suitable hard bottom areas down to > 150 m depth. Poorly sampled habitats with predicted presence along Algeria, Alboran Sea and adjacent Atlantic coasts encourage further investigation. We propose that surveys of target areas from the predicted distribution map, together with local expert knowledge, may lead to discoveries of new P. clavata sites and identify priority conservation areas.  
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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 2045-2322 ISBN Médium  
  Région Expédition Conférence  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1680  
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Auteur Panfili, J.; Darnaude, A.M.; Vigliola, L.; Jacquart, A.; Labonne, M.; Gilles, S. url  doi
openurl 
  Titre Experimental evidence of complex relationships between the ambient salinity and the strontium signature of fish otoliths Type Article scientifique
  Année 2015 Publication Revue Abrégée Journal of Experimental Marine Biology and Ecology  
  Volume 467 Numéro Pages 65-70  
  Mots-Clés Euryhaline tilapia; Otolith microchemistry; Salinity; Sarotherodon melanotheron heudelotii; Strontium; Validation  
  Résumé The otolith strontium:calcium ratio (Sr:Ca) has been widely used to assess the connectivity between fish populations in ocean, estuarine and freshwater environments as the concentration of Sr in the otoliths is strongly correlated with water salinity. This correlation was tested experimentally in hypersaline conditions by submitting the extremely euryhaline tilapia species Sarotherodon melanotheron heudelotii (Cichlidae), found throughout West African continental waters and commonly used as an aquaculture species, to a strong salinity gradient (15–106). Experimental and control individuals were reared from birth in a closed system at a constant salinity of 10 and injected with oxytetracycline (OTC) to mark the otoliths at the beginning of the experiment. Randomly selected control fish were maintained for 75 days at salinities of 10–20. The remaining experimental fish were acclimated to a salinity above 100 which was reduced by 10 each week to a salinity of 20. The salinity and temperature of the water were recorded every day and the Sr concentrations in the water were measured weekly by solution-based ICP-MS. The fish from the control and experimental groups were sampled weekly and otolith transverse sections were prepared for Sr:Ca measurements by laser ablation ICP-MS. No significant difference in the otolith growth rates after OTC marking was found between the control and experimental groups (ANCOVA, p = 0.63), showing that the experimental design did not affect fish growth. The Sr concentration in the water was closely related to ambient salinity (positive linear regression, R2 = 0.96). For most of the fish tested (~ 80%), the relationship between otolith Sr:Ca and salinity was positive but nonlinear (power law, R2 = 0.77 on log–log plot). However, about 20% of individuals from both the control and the experimental groups showed consistently low Sr:Ca ratios irrespective of the salinity, suggesting that the Sr incorporation into the otoliths in these fish was strongly regulated. This shows that there is high variability between individuals in the regulation of Sr incorporation by a euryhaline species and indicates that otolith datasets for ecological applications should be interpreted with caution.  
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  ISSN 0022-0981 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1259  
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Auteur Serandour, A.L.; Ledreux, A.; Morin, B.; Derick, S.; Augier, E.; Lanceleur, R.; Hamlaoui, S.; Moukha, S.; Furger, C.; Bire, R.; Krys, S.; Fessard, V.; Troussellier, M.; Bernard, C. url  doi
openurl 
  Titre Collaborative study for the detection of toxic compounds in shellfish extracts using cell-based assays. Part I: screening strategy and pre-validation study with lipophilic marine toxins Type Article scientifique
  Année 2012 Publication Revue Abrégée Anal. Bioanal. Chem.  
  Volume 403 Numéro 7 Pages 1983-1993  
  Mots-Clés Cell-based assays; Collaborative study; Lipophilic phycotoxins; azaspiracid-1; bioassays; cosmetic ingredients; cytotoxicity; cytotoxicity test; epithelial-cells; eye irritation tests; fluorometric microplate assay; interlaboratory validation; neuro-2a; okadaic acid  
  Résumé Human poisoning due to consumption of seafood contaminated with phycotoxins is a worldwide problem, and routine monitoring programs have been implemented in various countries to protect human consumers. Following successive episodes of unexplained shellfish toxicity since 2005 in the Arcachon Bay on the French Atlantic coast, a national research program was set up to investigate these atypical toxic events. Part of this program was devoted to fit-for-purpose cell-based assays (CBA) as complementary tools to collect toxicity data on atypical positive-mouse bioassay shellfish extracts. A collaborative study involving five laboratories was conducted. The responses of human hepatic (HepG2), human intestinal (Caco2), and mouse neuronal (Neuro2a) cell lines exposed to three known lipophilic phycotoxins-okadaic acid (OA), azaspiracid-1 (AZA1), and pectenotoxin-2 (PTX2)-were investigated. A screening strategy composed of standard operating procedures and a decision tree for dose-response modeling and assay validation were designed after a round of “trial-and-error” process. For each toxin, the shape of the concentration-response curves and the IC50 values were determined on the three cell lines. Whereas OA induced a similar response irrespective of the cell line (complete sigmoid), PTX2 was shown to be less toxic. AZA1 induced cytotoxicity only on HepG2 and Neuro2a, but not on Caco2. Intra- and inter-laboratory coefficients of variation of cell responses were large, with mean values ranging from 35 to 54 % and from 37 to 48 %, respectively. Investigating the responses of the selected cell lines to well-known toxins is the first step supporting the use of CBA among the panel of methods for characterizing atypical shellfish toxicity. Considering these successful results, the CBA strategy will be further applied to extracts of negative, spiked, and naturally contaminated shellfish tissues.  
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  Langue English Langue du Résumé Titre Original  
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  Volume de collection Numéro de collection Edition  
  ISSN 1618-2642 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 469  
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Auteur Walker, E.; Bez, N. url  doi
openurl 
  Titre A pioneer validation of a state-space model of vessel trajectories (VMS) with observers' data Type Article scientifique
  Année 2010 Publication Revue Abrégée Ecological Modelling  
  Volume 221 Numéro Pages 2008-2017  
  Mots-Clés Bayes; data; Markov; model; Monitoring; Observers'; purse-seiners; state-space; Systems; Trajectory; Tropical; tuna; Validation; Vessel; (Vms)  
  Résumé In the context of the expansion of animal tracking and bio-logging, state-space models have been developed with the objective to characterise animals' trajectories and to understand the factors controlling their behaviour. In the fisheries community, the electronic tagging of vessels commonly designated by Vessel Monitoring Systems (VMS) is developing and provides a new insight for the understanding, the analysis and the modelling of the trajectories of vessels and their prospecting behaviour. VMS data are thus a clue for the proper definition of fishing effort which remains a fundamental parameter of tuna stock assessments. In this context, we used the VMS (recording of hourly positions) of the French tropical tuna purse-seiners operating in the Indian Ocean to characterise three types of movement (states) on the VMS trajectories (stillness, tracking, and cruising). Based on empirical evidences, and on the regular frequency of VMS acquisition, this was achieved by the development of a Bayesian Hidden Markov model for the speeds and turning angles derived from the hourly steps of the trajectories. In a second phase, states were related to activities disentangling stillness into fishing or stop at sea. Finally the quality of the model performances was rigorously quantified thanks to observers' data. Confronting model prediction and true activities allowed estimating that 10% of the hourly steps were misclassified. The assumptions and model' choices are discussed, highlighting the fact that VMS data and observers' data having different time resolutions, the effective use of validating data was troublesome. However, without validation, these analyses remain speculative. The validation part of this work represents an important step for the operational use of state-space models in ecology in the broad sense (predators' tracking data, e.g. birds or mammals trajectories).  
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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 0304-3800 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel LL @ pixluser @ collection 112  
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