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Auteur Benedetti, F.; Vogt, M.; Righetti, D.; Guilhaumon, F.; Ayata, S.-D.
Titre Do functional groups of planktonic copepods differ in their ecological niches? Type Article scientifique
Année 2018 Publication Revue Abrégée J. Biogeogr.
Volume 45 Numéro 3 Pages 604-616
Mots-Clés climate-change; copepods; species distribution models; north-atlantic; calanus-finmarchicus; mediterranean sea; environmental niche; functional groups; lipid pump; marine ecosystem; oithona-similis; pseudo-absences; trait biogeography; zooplankton; zooplankton fecal pellets
Résumé Aim: To assess the degree of overlap between the environmental niches of marine planktonic copepods and test if the distribution of copepod functional groups differs across environmental gradients. Location: The Mediterranean Sea. Methods: Functional groups were defined based on clustering of functional traits in 106 marine copepod species using a multivariate ordination analysis. Functional traits included maximum body length, feeding mode, spawning strategy and trophic group. Simultaneously, the global distribution of the species was used to model their environmental niches with six environmental variables. For each of these predictors, four niche parameters were derived from the univariate response curve of each species to summarise their environmental preferences and ordinate the species in niche space through a PCA. Finally, the differences in the position in niche space of functional groups were tested with variance analysis. Results: We identified seven copepod functional groups with different distributions along the environmental gradients covered by our study. While carnivorous functional groups were affiliated with oligotrophic and tropical conditions, large and small current-feeding herbivores are associated with colder, more seasonally varying and productive conditions. Small cruising detritivores and other small current-feeding herbivores were not affiliated with specific conditions as their constituting species were scattered in niche space. Main conclusions: Since copepod functional groups occupy distinct ecological niches, ecosystem processes related to these groups are expected to vary across environmental gradients. Conditions favouring large current-feeding herbivores should allow for enhanced fluxes of energy and nutrients through Mediterranean Sea ecosystems, while such fluxes should be weakened where large carnivores and small passive ambush-feeding copepods dominate. Our study supports the development of trait-based zooplankton functional groups in marine ecosystem models.
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Langue (up) English Langue du Résumé Titre Original
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ISSN 0305-0270 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2311
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Auteur Ferrari, S.; Horri, K.; Allal, F.; Vergnet, A.; Benhaim, D.; Vandeputte, M.; Chatain, B.; Begout, M.-L.
Titre Heritability of Boldness and Hypoxia Avoidance in European Seabass, Dicentrarchus labrax Type Article scientifique
Année 2016 Publication Revue Abrégée PLoS One
Volume 11 Numéro 12 Pages e0168506
Mots-Clés atlantic salmon; behavioral plasticity; confinement stress; individual-differences; rainbow-trout; rearing conditions; Risk-taking; salmon salmo-salar; stress-coping styles; trout oncorhynchus-mykiss
Résumé To understand the genetic basis of coping style in European seabass, fish from a full factorial mating (10 females x 50 males) were reared in common garden and individually tagged. Individuals coping style was characterized through behavior tests at four different ages, categorizing fish into proactive or reactive: a hypoxia avoidance test (at 255 days post hatching, dph) and 3 risk-taking tests (at 276, 286 and 304 dph). We observed significant heritability of the coping style, higher for the average of risk-taking scores (h(2) = 0.45 +/- 0.14) than for the hypoxia avoidance test (h(2) = 0.19 +/- 0.10). The genetic correlations between the three risk-taking scores were very high (r(A) = 0.96-0.99) showing that although their repeatability was moderately high (r(P) = 0.64-0.72), successive risk-taking tests evaluated the same genetic variation. A mild genetic correlation between the results of the hypoxia avoidance test and the average of risk-taking scores (0.45 +/- 0.27) suggested that hypoxia avoidance and risk-taking tests do not address exactly the same behavioral and physiological responses. Genetic correlations between weight and risk taking traits showed negative values whatever the test used in our population i.e. reactive individual weights were larger. The results of this quantitative genetic analysis suggest a potential for the development of selection programs based on coping styles that could increase seabass welfare without altering growth performances. Overall, it also contributes to a better understanding of the origin and the significance of individual behavioral differences.
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Langue (up) English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1932-6203 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2071
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Auteur de Verdal, H.; O'Connell, C.M.; Mekkawy, W.; Vandeputte, M.; Chatain, B.; Begout, M.-L.; Benzie, J.A.H.
Titre Agonistic behaviour and feed efficiency in juvenile Nile tilapia Oreochromis niloticus Type Article scientifique
Année 2019 Publication Revue Abrégée Aquaculture
Volume 505 Numéro Pages 271-279
Mots-Clés Agonstic behaviour; arctic charr; atlantic salmon; brain serotonergic activity; brown trout; conversion ratio; Correlation; dominance relationships; Feed efficiency; food acquisition; genetic-improvement; Nile tilapia; Performances; salvelinus-alpinus; social-status
Résumé Given the strong effects of behavioural hierarchies on growth in many cultured species and the key role of feed efficiency in aquaculture economics, understanding the nature of the interaction of these variables is important for the sustainability of aquaculture. The relationship between agonistic behaviour, growth and feed efficiency in Nile tilapia, Oreochromis niloticus, was studied by rearing 120 fish in eight aquaria. Fish were video-recorded to estimate the occurrence of agonistic behaviour during a fasting and a refeeding period. Growth, feed intake and feed conversion efficiency (FCE – calculated as the inverse of feed conversion ratio (FCR)) were subsequently measured individually for each fish. Fish showed 58% less agonistic traits during the fasting period compared to the feeding period, but generally, an aggressive fish during the fasting period was also aggressive during the refeeding period. The nature of agonistic behaviours between individuals was used to assess the presence of hierarchical relationships between fish. There were dominance hierarchies established in each experimental aquarium that despite minor shifts were maintained throughout the experiment. Agonistic behaviours were strongly correlated with each other, the aggression Index (AI) and with hierarchy rank. PCA analysis of the agonistic behaviours summarising the behavioural information showed little or no correlation between agonistic behaviour, fish growth or FCE. FCE was correlated with body weight gain (BWG). These results suggest that agonistic interactions in juvenile Nile tilapia do not have a large impact on growth and feed conversion efficiency.
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Editeur Lieu de Publication Éditeur
Langue (up) English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0044-8486 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2583
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Auteur Torres-Irineo, E.; Dreyfus-Leon, M.; Gaertner, D.; Salas, S.; Marchal, P.
Titre Adaptive responses of tropical tuna purse-seiners under temporal regulations Type Article scientifique
Année 2017 Publication Revue Abrégée Ambio
Volume 46 Numéro 1 Pages 88-97
Mots-Clés atlantic; behavior; Closed season; eastern pacific-ocean; eastern tropical pacific; Fisher behaviour; Fisheries management; fishing strategies; fleet dynamics; mixed fisheries; model; Purse-seine fishing; state; trawlers; Tropical tuna
Résumé The failure to achieve fisheries management objectives has been broadly discussed in international meetings. Measuring the effects of fishery regulations is difficult due to the lack of detailed information. The yellowfin tuna fishery in the eastern Pacific Ocean offers an opportunity to evaluate the fishers' responses to temporal regulations. We used data from observers on-board Mexican purse-seine fleet, which is the main fleet fishing on dolphin-associated tuna schools. In 2002, the Inter-American Tropical Tuna Commission implemented a closed season to reduce fishing effort for this fishery. For the period 1992-2008, we analysed three fishery indicators using generalized estimating equations to evaluate the fishers' response to the closure. We found that purse-seiners decreased their time spent in port, increased their fishing sets, and maintained their proportion of successful fishing sets. Our results highlight the relevance of accounting for the fisher behaviour to understand fisheries dynamics when establishing management regulations.
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Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
Langue (up) English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0044-7447 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2072
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Auteur Coz, R.; Ouisse, V.; Artero, C.; Carpentier, A.; Crave, A.; Feunteun, E.; Olivier, J.M.; Perrin, B.; Ysnel, F.
Titre Development of a new standardised method for sustainable monitoring of the vulnerable pink sea fan Eunicella verrucosa Type Article scientifique
Année 2012 Publication Revue Abrégée Marine Biology
Volume 159 Numéro 6 Pages 1375-1388
Mots-Clés atlantic canada; cavolini coelenterata octocorallia; channel; gonadal development; gorgonian paramuricea-clavata; marine invertebrate; mediterranean-sea; modular growth; movement; northeast; singularis esper; water
Résumé The aim of this survey was to test a standardised method to follow the demographic evolution of a dense aggregative 'forest' population of the temperate gorgonian Eunicella verrucosa (Octocorallia, Gorgoniidae) using in situ photographic recordings. Distribution, density, growth and demographic evolution of the colonies was compared along two parallel transects. Computer treatment allowed the estimation of the total branch fan surface area, and the individual growth of tagged colonies was determined by measuring the increase in this surface area, using consecutive photographs taken at two-year intervals. To integrate the potential bias of branch overlapping, we proposed a correction factor between the in situ photographic surface area and the surface area of the gorgonian calculated from ex situ photographic surface area with all branches deployed. The surface-frequency distribution of colonies was converted to estimated-age-frequency distribution using an estimated growth curve based on the net growth rate. The technique used revealed significant differences in population structure and the dynamics of gorgonian colonies, as the two transects appeared to be influenced by different environmental conditions. The recruitment also seemed to vary according to year and transect, resulting in different densities. Our work showed clear results in characterising the variations of gorgonian demographic evolution at a small spatial scale; thus, it is assumed that this method could be a sustainable tool for coastal environmental managers.
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Langue (up) English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0025-3162 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 539
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