|   | 
Détails
   web
Enregistrements
Auteur Viblanc, V.A.; Saraux, C.; Malosse, N.; Groscolas, R.
Titre Energetic adjustments in freely breeding-fasting king penguins: does colony density matter? Type (up) Article scientifique
Année 2014 Publication Revue Abrégée Functional Ecology
Volume Numéro Pages
Mots-Clés body temperature; energy expenditure; fasting; heart rate; physical activity; Seabird; social density; Stress
Résumé * For seabirds that forage at sea but breed while fasting on land, successful reproduction depends on the effective management of energy stores. Additionally, breeding often means aggregating in dense colonies where social stress may affect energy budgets. * Male king penguins (Aptenodytes patagonicus) fast for remarkably long periods (up to 1·5 months) while courting and incubating ashore. Although their fasting capacities have been well investigated in captivity, we still know very little about the energetics of freely breeding birds. * We monitored heart rate (HR, a proxy to energy expenditure), body temperature and physical activity of male king penguins during their courtship and first incubation shift in a colony of some 24 000 freely breeding pairs. Males were breeding either under low but increasing colony density (early breeders) or at high and stable density (late breeders). * In early breeders, daily mean and resting HR decreased during courtship but increased again 3 days before egg laying and during incubation. In late breeders, HR remained stable throughout this same breeding period. Interestingly, the daily increase in resting HR we observed in early breeders was strongly associated with a marked increase in colony density over time. This finding remained significant even after controlling for climate effects. * In both early and late breeders, courtship and incubation were associated with a progressive decrease in physical activity, whereas core body temperature remained unchanged. * We discuss the roles of decreased physical activity and thermoregulatory strategies in sustaining the long courtship–incubation fast of male king penguins. We also draw attention to a potential role of conspecific density in affecting the energetics of breeding-fasting seabirds, that is, a potential energy cost to coloniality.
Adresse
Auteur institutionnel Thèse
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 1365-2435 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel LL @ pixluser @ collection 320
Lien permanent pour cet enregistrement
 

 
Auteur Joo, R.; Bertrand, A.; Bouchon, M.; Chaigneau, A.; Demarcq, H.; Tam, J.; Simier, M.; Gutiérrez, D.; Gutiérrez, M.; Segura, M.; Fablet, R.; Bertrand, S.
Titre Ecosystem scenarios shape fishermen spatial behavior. The case of the Peruvian anchovy fishery in the Northern Humboldt Current System Type (up) Article scientifique
Année 2014 Publication Revue Abrégée Progress in Oceanography
Volume 128 Numéro Pages 60-73
Mots-Clés
Résumé A major goal in marine ecology is the understanding of the interactions between the dynamics of the different ecosystem components, from physics to top predators. While fishermen are among the main top predators at sea, almost none of the existing studies on ecology from physics to top predators contemplate fishermen as part of the system. The present work focuses on the coastal processes in the Northern Humboldt Current System, which encompasses both an intense climatic variability and the largest monospecific fishery of the world. From concomitant satellite, acoustic survey and Vessel Monitoring System data (∼90,000 fishing trips) for a ten-year period (2000–2009), we quantify the associations between the dynamics of the spatial behavior of fishermen, environmental conditions and anchovy (Engraulis ringens) biomass and spatial distribution. Using multivariate statistical analyses we show that environmental and anchovy conditions do significantly shape fishermen spatial behavior and present evidences that environmental fluctuations smoothed out along trophic levels. We propose a retrospective analysis of the study period in the light of the ecosystem scenarios evidenced and we finally discuss the potential use of fishermen spatial behavior as ecosystem indicator.
Adresse
Auteur institutionnel Thèse
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 0079-6611 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel LL @ pixluser @ collection 321
Lien permanent pour cet enregistrement
 

 
Auteur Fromentin, J.-M.; Bonhommeau, S.; Arrizabalaga, H.; Kell, L.T.
Titre The spectre of uncertainty in management of exploited fish stocks: The illustrative case of Atlantic bluefin tuna Type (up) Article scientifique
Année 2014 Publication Revue Abrégée Marine Policy
Volume 47 Numéro Pages 8-14
Mots-Clés tuna
Résumé
Adresse
Auteur institutionnel Thèse
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 0308-597x ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel LL @ pixluser @ collection 323
Lien permanent pour cet enregistrement
 

 
Auteur Albouy, C.; Velez, L.; Coll, M.; Colloca, F.; Le Loc'h, F.; Mouillot, D.; Gravel, D.
Titre From projected species distribution to food-web structure under climate change Type (up) Article scientifique
Année 2014 Publication Revue Abrégée Global Change Biology
Volume 20 Numéro 3 Pages 730-741
Mots-Clés climate change; connectance; fish body size; food-webs; generality; Mediterranean Sea; metaweb; niche model; vulnerability
Résumé
Adresse
Auteur institutionnel Thèse
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 1354-1013 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel LL @ pixluser @ collection 324
Lien permanent pour cet enregistrement
 

 
Auteur Alegre, A.; Ménard, F.; Tafur, R.; Espinoza, P.; Arguelles, J.; Maehara, V.; Flores, O.; Simier, M.; Bertrand, A.
Titre Comprehensive model of jumbo squid Dosidicus gigas trophic ecology in the Northern Humboldt Current System Type (up) Article scientifique
Année 2014 Publication Revue Abrégée Plos One
Volume 9 Numéro 1 Pages
Mots-Clés
Résumé The jumbo squid Dosidicus gigas plays an important role in marine food webs both as predator and prey. We investigated the ontogenetic and spatiotemporal variability of the diet composition of jumbo squid in the northern Humboldt Current system. For that purpose we applied several statistical methods to an extensive dataset of 3,618 jumbo squid non empty stomachs collected off Peru from 2004 to 2011. A total of 55 prey taxa was identified that we aggregated into eleven groups. Our results evidenced a large variability in prey composition as already observed in other systems. However, our data do not support the hypothesis that jumbo squids select the most abundant or energetic taxon in a prey assemblage, neglecting the other available prey. Indeed, multinomial model predictions showed that stomach fullness increased with the number of prey taxa, while most stomachs with low contents contained one or two prey taxa only. Our results therefore question the common hypothesis that predators seek locally dense aggregations of monospecific prey. In addition D. gigas consumes very few anchovy Engraulis ringens in Peru, whereas a tremendous biomass of anchovy is potentially available. It seems that D. gigas cannot reach the oxygen unsaturated waters very close to the coast, where the bulk of anchovy occurs. Indeed, even if jumbo squid can forage in hypoxic deep waters during the day, surface normoxic waters are then required to recover its maintenance respiration (or energy?). Oxygen concentration could thus limit the co-occurrence of both species and then preclude predator-prey interactions. Finally we propose a conceptual model illustrating the opportunistic foraging behaviour of jumbo squid impacted by ontogenetic migration and potentially constrained by oxygen saturation in surface waters.
Adresse
Auteur institutionnel Thèse
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 1932-6203 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel LL @ pixluser @ collection 325
Lien permanent pour cet enregistrement