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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. url  doi
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  Titre Ecosystem scenarios shape fishermen spatial behavior. The case of the Peruvian anchovy fishery in the Northern Humboldt Current System Type 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.  
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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 (up) 0079-6611 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel LL @ pixluser @ collection 321  
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Auteur Garavelli, L.; Kaplan, D.; Colas, F.; Stotz, W.; Yannicelli, B.; Lett, C. url  doi
openurl 
  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  
  Mots-Clés  
  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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  Éditeur de collection Titre de collection Titre de collection Abrégé  
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  ISSN (up) 0079-6611 ISBN Médium  
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  Numéro d'Appel LL @ pixluser @ collection 359  
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Auteur Hernandez, O.; Lehodey, P.; Senina, I.; Echevin, V.; Ayon, P.; Bertrand, A.; Gaspar, P. url  doi
openurl 
  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  
  Mots-Clés  
  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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  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
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  ISSN (up) 0079-6611 ISBN Médium  
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  Numéro d'Appel LL @ pixluser @ collection 362  
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Auteur Merino, G.; Barange, M.; Fernandes, J.A.; Mullon, C.; Cheung, W.; Trenkel, V.; Lam, V. url  doi
openurl 
  Titre Estimating the economic loss of recent North Atlantic fisheries management Type Article scientifique
  Année 2014 Publication Revue Abrégée Progress in Oceanography  
  Volume Numéro Pages 314-323  
  Mots-Clés  
  Résumé It is accepted that world’s fisheries are not generally exploited at their biological or their economic optimum. Most fisheries assessments focus on the biological capacity of fish stocks to respond to harvesting and few have attempted to estimate the economic efficiency at which ecosystems are exploited. The latter is important as fisheries contribute considerably to the economic development of many coastal communities. Here we estimate the overall potential economic rent for the fishing industry in the North Atlantic to be B€ 12.85, compared to current estimated profits of B€ 0.63. The difference between the potential and the net profits obtained from North Atlantic fisheries is therefore B€ 12.22. In order to increase the profits of North Atlantic fisheries to a maximum, total fish biomass would have to be rebuilt to 108 Mt (2.4 times more than present) by reducing current total fishing effort by 53%. Stochastic simulations were undertaken to estimate the uncertainty associated with the aggregate bioeconomic model that we use and we estimate the economic loss NA fisheries in a range of 2.5 and 32 billion of euro. We provide economic justification for maintaining or restoring fish stocks to above their MSY biomass levels. Our conclusions are consistent with similar global scale studies.  
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  Éditeur de collection Titre de collection North Atlantic Ecosystems, the role of climate and anthropogenic forcing on their structure and function Titre de collection Abrégé  
  Volume de collection 129, Part B Numéro de collection Edition  
  ISSN (up) 0079-6611 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1200  
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Auteur Peraltilla, S.; Bertrand, S. url  doi
openurl 
  Titre In situ measurements of the speed of Peruvian anchovy schools Type Article scientifique
  Année 2014 Publication Revue Abrégée Fisheries Research  
  Volume 149 Numéro Pages 92-94  
  Mots-Clés Multibeam sonar; Peruvian anchovy; School speed  
  Résumé While speed of fish schools is critical information for parameterizing numerous ecosystem models and evaluating fishery management options, it is poorly documented. Here we present results of in situ measurements of the speed of Peruvian anchovy schools, a small pelagic species that sustain the world's largest mono-specific fishery. Instantaneous school speed was in average 0.6 ms(-1), authorizing theoretical maximum displacements of similar to 26 km day(-1).  
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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 (up) 0165-7836 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel LL @ pixluser @ collection 331  
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