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Auteur Bonhommeau, S.; Nieblas, A.E.; Chassot, E.; Kaplan, D.; Dubroca, L.; Manacorda, C.; Barde, J.; Le Pape, O.
Titre Reply to Feeley and Machovina : trophic ecology complements estimates of land use change due to food production Type Article scientifique
Année 2014 Publication Revue Abrégée Proceedings of the National Academy of Sciences of the United States of America
Volume 111 Numéro 9 Pages
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ISSN 0027-8424 ISBN Médium
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Numéro d'Appel (up) LL @ pixluser @ collection 354
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Auteur Boyd, C.; Punt, A.E.; Weimerskirch, H.; Bertrand, S.
Titre Movement models provide insights into variation in the foraging effort of central place foragers Type Article scientifique
Année 2014 Publication Revue Abrégée Ecological Modelling
Volume 286 Numéro Pages 13-25
Mots-Clés Animal movement; Foraging ecology; Hidden Markov model; Provisioning theory; Seabirds; Sula variegata
Résumé Ecology and conservation depend on an understanding of how animals adjust their behaviour patterns in response to changes in their environment. Central place foragers (CPFs) are well-suited for developing ecological models of adaptive processes because their objective functions and operational constraints can be reasonably inferred. Central place foraging and provisioning theory provide the theoretical framework for this analysis. Analysis of CPF time allocation and energy budgets can provide insights into their strategies for responding to environmental variation. However, until recently, suitable high-resolution data on the behaviour of seabirds and other CPFs at sea have not been available. Previous studies of breeding seabirds have investigated variation in foraging trip duration and colony attendance, but few studies have analyzed variation in time allocation within foraging trips. Here, we develop a conceptual energy-based model for analysing variation in the time allocation of CPFs during foraging trips, and apply it to the movement patterns of Peruvian boobies (Sula variegata). Foraging trips of Peruvian boobies, recorded using high-resolution global positioning systems (GPS), were first partitioned into movement modes consistent with travel and foraging behaviours using a hidden Markov model (HMM) adapted to account for gaps in the GPS tracks associated with diving behaviour. Analysis of the HMM results based on the conceptual model indicated that differences in foraging effort between two treatments were best explained by a combination of differences in travel time and in time spent searching for prey. The conceptual model provides the basis for an integrated approach to analysis of variation in foraging strategies in which identification of various behaviours is coupled with assessments of time and energy budgets. This integrated approach can contribute to greater understanding of the processes determining foraging strategies and the limits to these strategies in the context of competition for resources and global climate change.
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ISSN 0304-3800 ISBN Médium
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Numéro d'Appel (up) LL @ pixluser @ collection 355
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Auteur Cuif, M.; Keller, F.; Chateau, O.; Kaplan, D.; Labonne, M.; Lett, C.; Vigliola, L.
Titre Evaluation of transgenerational isotope labeling of embryonic otoliths in a coral reef damselfish with single and repeated injections of enriched (137)Barium Type Article scientifique
Année 2014 Publication Revue Abrégée Journal of Experimental Marine Biology and Ecology
Volume 459 Numéro Pages 151-159
Mots-Clés Barium isotopes; Connectivity; Dascyllus aruanus; La-Icp-Ms; microchemistry; Otolith; Transgenerational marking
Résumé Quantifying the larval dispersal component of population connectivity is extremely challenging due to the many difficulties associated with directly observing larvae in their marine environment. Transgenerational isotope labeling is a recent empirical technique that addresses this challenge. It relies on the transmission of an artificially enriched stable isotope (e.g., Ba-137) from gravid females to the embryonic otoliths of their offspring, allowing for mass permanent marking of larvae. Before implementing transgenerational isotope labeling in the wild, it is essential to investigate the transmission longevity of the mark from females to larvae and to assess the potential negative effects on females and their offspring. We injected females of the Humbug damselfish, Dascyllus aruanus, with an enriched Ba-137 solution and reared the resulting progeny to test the marking success and the transmission longevity of the mark, as well as determine potential effects of transgenerational isotope labeling on spawning frequency and size of 1-day eggs and 2-day larvae. Three different single-injection dosages (0.5, 1 and 5 mu g of Ba-137 g(-1) fish weight) were tested, as well as monthly repeated injections of the lowest dosage over a whole reproductive season. We implemented a new method that allows extracting otoliths of newly hatched larvae and analyzing them using laser ablation coupled plasma mass spectrometry (ICP-MS). We showed that for D. aruanus, injection with a low dose (0.5 mu g Ba-137 g(-1), fish weight) produced consistently significantly marked larvae with a half-life for successful enriched Ba mark transmission of approximately 1 month, and that monthly repeated injections of this dose did not negatively impact spawning success or condition of eggs and larvae. Monthly repeated injections of enriched Ba isotope injections at 0.5 mu g Ba-137 g(-1) fish weight will therefore present an effective means of mass marking D. aruanus larvae throughout an entire reproductive season.
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Volume de collection Numéro de collection Edition
ISSN 0022-0981 ISBN Médium
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Numéro d'Appel (up) LL @ pixluser @ collection 357
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Auteur Espinoza, P.; Bertrand, A.
Titre Ontogenetic and spatiotemporal variability in anchoveta Engraulis ringens diet off Peru Type Article scientifique
Année 2014 Publication Revue Abrégée Journal of Fish Biology
Volume 84 Numéro 2 Pages 422-435
Mots-Clés euphausiids; Humboldt Current system; oxygen; Peruvian anchovy; spatiotemporal variability; trophic ecology
Résumé In this study, historical data available since 1954 were used to get new insight to ontogenetic and spatiotemporal variability in Peruvian anchovy or anchoveta Engraulis ringens diet. Whatever the period, E. ringens foraged mainly on macrozooplankton and the importance of euphausiids in E. ringens diet appears directly related to euphausiids abundance. This bottom-up effect is also observed at smaller scale because the euphausiids fraction increased with E. ringens total length and euphausiids accessibility. Selecting the largest prey, the euphausiids, provides an energetic advantage for E. ringens in its ecosystem where oxygen depletion imposes strong metabolic constraints on pelagic fishes. This study illustrates the plasticity of E. ringens that allows it to cope with its highly variable environment.
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Volume de collection Numéro de collection Edition
ISSN 0022-1112 ISBN Médium
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Numéro d'Appel (up) LL @ pixluser @ collection 358
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Auteur Garavelli, L.; Kaplan, D.; Colas, F.; Stotz, W.; Yannicelli, B.; Lett, C.
Titre Identifying appropriate spatial scales for marine conservation and management using a larval dispersal model : the case of Concholepas concholepas (loco) in Chile Type Article scientifique
Année 2014 Publication Revue Abrégée Progress in Oceanography
Volume 124 Numéro Pages 42-53
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Résumé Along the coast of Chile, fisheries targeting the marine gastropod Concholepas concholepas, commonly named “loco”, were highly valuable until the end of the 80s when catches declined significantly. Since the late 90s, a management plan based on territorial-user-rights areas has been implemented, with limited effect on stock recovery. More effective loco conservation and management is impeded by lack of information regarding connectivity via larval dispersal between these individually-managed areas. To develop a regional view of loco connectivity, we integrate loco life history information into a biophysical, individual-based larval dispersal model. This model is used to evaluate scales of loco connectivity and seasonality in connectivity patterns, as well as to partition the coast into largely disconnected subpopulations using a recently developed connectivity-matrix clustering algorithm. We find mean dispersal distances ranging from 170 to 220 km depending on release depth of larvae and planktonic larval duration. Settlement success levels depend quantitatively on the physical and biological processes included in the model, but connectivity patterns remain qualitatively similar. Model estimates of settlement success peak for larval release dates in late austral autumn, consistent with field results and with favorable conditions for larval coastal retention due to weak upwelling during austral autumn. Despite the relatively homogeneous Chilean coastline, distinct subpopulations with minimal connectivity between them are readily identifiable. Barriers to connectivity that are robust to changes in model configuration exist at 23 degrees S and 29 degrees S latitudes. These zones are all associated with important headlands and embayments of the Chilean coast.
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ISSN 0079-6611 ISBN Médium
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Numéro d'Appel (up) LL @ pixluser @ collection 359
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