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Auteur van der Geest, M.; Sall, A.A.; Ely, S.O.; Nauta, R.W.; van Gils, J.A.; Piersma, T.
Titre Nutritional and reproductive strategies in a chemsoymbiotic bivalve living in a tropical intertidal seagrass bed Type Article scientifique
Année 2014 Publication Revue Abrégée Marine Ecology Progress Series
Volume 501 Numéro Pages 113-126
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Numéro d'Appel MARBEC @ alain.herve @ 848 collection 1378
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Auteur BORDIER, C.; SARAUX, C.; VIBLANC, V.A.; GACHOT-NEVEU, H.; BEAUGEY, M.; LE MAHO, Y.; LE BOHEC, C.
Titre Inter-Annual Variability of Fledgling Sex Ratio in King Penguins Type Article scientifique
Année 2014 Publication Revue Abrégée Plos One
Volume 9 Numéro 12 Pages 1-17
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Résumé As the number of breeding pairs depends on the adult sex ratio in a monogamous species with biparental care, investigating sex-ratio variability in natural populations is essential to understand population dynamics. Using 10 years of data (20002009) in a seasonally monogamous seabird, the king penguin (Aptenodytes patagonicus), we investigated the annual sex ratio at fledging, and the potential environmental causes for its variation. Over more than 4000 birds, the annual sex ratio at fledging was highly variable (ranging from 44.4% to 58.3% of males), and on average slightly biased towards males (51.6%). Yearly variation in sex-ratio bias was neither related to density within the colony, nor to global or local oceanographic conditions known to affect both the productivity and accessibility of penguin foraging areas. However, rising sea surface temperature coincided with an increase in fledging sex-ratio variability. Fledging sex ratio was also correlated with difference in body condition between male and female fledglings. When more males were produced in a given year, their body condition was higher (and reciprocally), suggesting that parents might adopt a sex-biased allocation strategy depending on yearly environmental conditions and/or that the effect of environmental parameters on chick condition and survival may be sex-dependent. The initial bias in sex ratio observed at the juvenile stage tended to return to 1:1 equilibrium upon first breeding attempts, as would be expected from Fisher's classic theory of offspring sex-ratio variation.
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ISSN 1932-6203 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1126
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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 LL @ pixluser @ collection 359
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Auteur LE MAHO, Y.; WHITTINGTON, J.D.; HANUISE, N.; PEREIRA, L.; BOUREAU, M.; BRUCKER, M.; CHATELAIN, N.; COURTECUISSE, J.; CRENNER, F.; FRIESS, B.; GROSBELLET, E.; KERNALEGUEN, L.; OLIVER, F.; SARAUX, C.; VETTER, N.; VIBLANC, V.A.; THIERRY, B.; TREMBLAY, P.; GROSCOLAS, R.; LE BOHEC, C.
Titre Rovers minimize human disturbance in research on wild animals Type Article scientifique
Année 2014 Publication Revue Abrégée Nature Methods
Volume 11 Numéro 12 Pages 1242-1244
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Résumé Investigating wild animals while minimizing human disturbance remains an important methodological challenge. When approached by a remote-operated vehicle (rover) which can be equipped to make radio-frequency identifications, wild penguins had significantly lower and shorter stress responses (determined by heart rate and behavior) than when approached by humans. Upon immobilization, the rover-unlike humans-did not disorganize colony structure, and stress rapidly ceased. Thus, rovers can reduce human disturbance of wild animals and the resulting scientific bias.
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ISSN 1548-7091 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1128
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Auteur Hernandez, O.; Lehodey, P.; Senina, I.; Echevin, V.; Ayon, P.; Bertrand, A.; Gaspar, P.
Titre Understanding mechanisms that control fish spawning and larval recruitment : parameter optimization of an Eulerian model (SEAPODYM-SP) with Peruvian anchovy and sardine eggs and larvae data Type Article scientifique
Année 2014 Publication Revue Abrégée Progress in Oceanography
Volume 123 Numéro Pages 105-122
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Résumé The Spatial Ecosystem And Populations Dynamics Model “SEAPODYM”, based on a system of Eulerian equations and initially developed for large pelagic fish (e.g., tuna), was modified to describe spawning habitat and eggs and larvae dynamics of small pelagic fish. The spawning habitat is critical since it controls the initial recruitment of larvae and the subsequent spatio-temporal variability of natural mortality during their drift with currents. A robust statistical approach based on Maximum Likelihood Estimation is presented to optimize the model parameters defining the spawning habitat and the eggs and larvae dynamics. To improve parameterization, eggs and larvae density observations are assimilated in the model. The model and its associated optimization approach allow investigating the significance of the mechanisms proposed to control fish spawning habitat and larval recruitment: temperature, prey abundance, trade-off between prey and predators, and retention and dispersion processes. An application to the Peruvian anchovy (Engraulis ringens) and sardine (Sardinops sagax) illustrates the ability of the model to simulate the main features of spatial dynamics of these two species in the Humboldt Current System. For both species, in climatological conditions, the main observed spatial patterns are well reproduced and are explained by the impact of prey and predator abundance and by physical retention with currents, while temperature has a lower impact. In agreement with observations, sardine larvae are mainly predicted in the northern part of the Peruvian shelf (5-10 degrees S), while anchovy larvae extend further south. Deoxygenation, which can potentially limit the accessibility of adult fish to spawning areas, does not appear to have an impact in our model setting. Conversely, the observed seasonality in spawning activity, especially the spawning rest period in austral autumn, is not well simulated. It is proposed that this seasonal cycle is more likely driven by the spatio-temporal dynamics of adult fish constituting the spawning biomass and not yet included in the model.
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ISSN 0079-6611 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 362
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