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Auteur Boyd, C.; Castillo, R.; Hunt, G.L.; Punt, A.E.; VanBlaricom, G.R.; Weimerskirch, H.; Bertrand, S. url  doi
openurl 
  Titre Predictive modelling of habitat selection by marine predators with respect to the abundance and depth distribution of pelagic prey Type Article scientifique
  Année 2015 Publication Revue Abrégée J Anim Ecol  
  Volume 84 Numéro 6 Pages 1575-1588  
  Mots-Clés central place foragers; Foraging ecology; habitat use; Humboldt Current system; predator–prey interactions; spatial distribution  
  Résumé * Understanding the ecological processes that underpin species distribution patterns is a fundamental goal in spatial ecology. However, developing predictive models of habitat use is challenging for species that forage in marine environments, as both predators and prey are often highly mobile and difficult to monitor. Consequently, few studies have developed resource selection functions for marine predators based directly on the abundance and distribution of their prey. * We analysed contemporaneous data on the diving locations of two seabird species, the shallow-diving Peruvian Booby (Sula variegata) and deeper diving Guanay Cormorant (Phalacrocorax bougainvilliorum), and the abundance and depth distribution of their main prey, Peruvian anchoveta (Engraulis ringens). Based on this unique data set, we developed resource selection functions to test the hypothesis that the probability of seabird diving behaviour at a given location is a function of the relative abundance of prey in the upper water column. * For both species, we show that the probability of diving behaviour is mostly explained by the distribution of prey at shallow depths. While the probability of diving behaviour increases sharply with prey abundance at relatively low levels of abundance, support for including abundance in addition to the depth distribution of prey is weak, suggesting that prey abundance was not a major factor determining the location of diving behaviour during the study period. * The study thus highlights the importance of the depth distribution of prey for two species of seabird with different diving capabilities. The results complement previous research that points towards the importance of oceanographic processes that enhance the accessibility of prey to seabirds. The implications are that locations where prey is predictably found at accessible depths may be more important for surface foragers, such as seabirds, than locations where prey is predictably abundant. * Analysis of the relative importance of abundance and accessibility is essential for the design and evaluation of effective management responses to reduced prey availability for seabirds and other top predators in marine systems.  
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  Langue en Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1365-2656 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1349  
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Auteur Boyd, C.; Grunbaum, D.; Hunt, G.L.; Punt, A.E.; Weimerskirch, H.; Bertrand, S. doi  openurl
  Titre Effects of variation in the abundance and distribution of prey on the foraging success of central place foragers Type Article scientifique
  Année 2017 Publication Revue Abrégée J. Appl. Ecol.  
  Volume 54 Numéro 5 Pages 1362-1372  
  Mots-Clés allocation; ecosystem; fisheries; Guanay Cormorant; guano-producing seabirds; Humboldt Current system; impact; indicators; marine spatial planning; Peruvian Booby; Phalacrocorax bougainvilliorum; predator-prey interactions; prey availability; seabird competition with fisheries; small pelagic fish; Sula variegata; upwelling system; variability  
  Résumé 1. Seabirds and pinnipeds are vulnerable to reductions in prey availability, especially during the breeding season when spatial constraints limit their adaptive capacity. There are growing concerns about the effects of fisheries on prey availability in regions where large commercial fisheries target forage fish. 2. For breeding seabirds and pinnipeds, prey availability depends on a combination of abundance, accessibility, patchiness and distance from the colony. An understanding of the aspects of prey availability that determine foraging success is essential for the design of effective management responses. 3. We used a mechanistic individual-based foraging model based on observed data for two sea-bird species, the Peruvian Booby Sula variegata and Guanay Cormorant Phalacrocorax bougainvilliorum, to simulate the foraging patterns of seabirds feeding on schooling fish. We ran the model over simulated prey fields representing eight possible combinations of high or low prey abundance, shallow or deep prey, and broadly distributed or spatially concentrated prey. 4. The results highlight the importance of the accessibility of prey. Depth distribution was the primary factor determining modelled foraging success for both species, followed by abundance, and then spatial configuration. 5. Synthesis and applications. The individual-based foraging model provides a spatially explicit framework for assessing the effects of fisheries on the foraging success of seabirds and other central place foragers, and for evaluating the potential effectiveness of marine-protected areas and other fisheries management strategies for safeguarding central place foragers in dynamic ecosystems. Our analysis indicates that broad-scale fisheries management strategies that maintain forage fish above critical biomass levels are essential, but may need to be supplemented by targeted actions, such as time-area closures, when environmental conditions lead to low prey abundance or reduce prey accessibility for seabirds or pinnipeds of conservation concern. The individual-based foraging model is adaptable and could be reconfigured for application to other species and systems.  
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  Editeur Lieu de Publication Éditeur  
  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0021-8901 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 2192  
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Auteur Espinoza, P.; Bertrand, A. url  doi
openurl 
  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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  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 0022-1112 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel LL @ pixluser @ collection 358  
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Auteur Garcon, V.; Karstensen, J.; Palacz, A.; Telszewski, M.; Aparco Lara, T.; Breitburg, D.; Chavez, F.; Coelho, P.; Cornejo-D'Ottone, M.; Santos, C.; Fiedler, B.; Gallo, N.D.; Gregoire, M.; Gutierrez, D.; Hernandez-Ayon, M.; Isensee, K.; Koslow, T.; Levin, L.; Marsac, F.; Maske, H.; Mbaye, B.C.; Montes, I.; Naqvi, W.; Pearlman, J.; Pinto, E.; Pitcher, G.; Pizarro, O.; Rose, K.; Shenoy, D.; Van der Plas, A.; Vito, M.R.; Weng, K. doi  openurl
  Titre Multidisciplinary Observing in the World Ocean's Oxygen Minimum Zone Regions: From Climate to Fish – The VOICE Initiative Type Article scientifique
  Année 2019 Publication Revue Abrégée Front. Mar. Sci.  
  Volume 6 Numéro Pages 722  
  Mots-Clés continental-shelf; demersal fishes; ecosystem; growth; habitat compression; humboldt current system; hypoxia; multidisciplinary; ocean observing system; oxycline; oxygen minimum zones; readiness level; reproduction; responses; variability  
  Résumé Multidisciplinary ocean observing activities provide critical ocean information to satisfy ever-changing socioeconomic needs and require coordinated implementation. The upper oxycline (transition between high and low oxygen waters) is fundamentally important for the ecosystem structure and can be a useful proxy for multiple observing objectives connected to eastern boundary systems (EBSs) that neighbor oxygen minimum zones (OMZs). The variability of the oxycline and its impact on the ecosystem (VOICE) initiative demonstrates how societal benefits drive the need for integration and optimization of biological, biogeochemical, and physical components of regional ocean observing related to EBS. In liaison with the Global Ocean Oxygen Network, VOICE creates a roadmap toward observation-model syntheses for a comprehensive understanding of selected oxycline-dependent objectives. Local to global effects, such as habitat compression or deoxygenation trends, prompt for comprehensive observing of the oxycline on various space and time scales, and for an increased awareness of its impact on ecosystem services. Building on the Framework for Ocean Observing (FOO), we present a first readiness level assessment for ocean observing of the oxycline in EBS. This was to determine current ocean observing design and future needs in EBS regions (e.g., the California Current System, the Equatorial Eastern Pacific off Ecuador, the Peru-Chile Current system, the Northern Benguela off Namibia, etc.) building on the FOO strategy. We choose regional champions to assess the ocean observing design elements proposed in the FOO, namely, requirement processes, coordination of observational elements, and data management and information products and the related best practices. The readiness level for the FOO elements was derived for each EBS through a similar and very general ad hoc questionnaire. Despite some weaknesses in the questionnaire design and its completion, an assessment was achievable. We found that fisheries and ecosystem management are a societal requirement for all regions, but maturity levels of observational elements and data management and information products differ substantially. Identification of relevant stakeholders, developing strategies for readiness level improvements, and building and sustaining infrastructure capacity to implement these strategies are fundamental milestones for the VOICE initiative over the next 2-5 years and beyond.  
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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN ISBN Médium  
  Région Expédition Conférence  
  Notes WOS:000502961900001 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2702  
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Auteur Passuni, G.; Barbraud, C.; Chaigneau, A.; Bertrand, A.; Oliveros-Ramos, R.; Ledesma, J.; Castillo, R.; Bouchon, M.; Bertrand, S. doi  openurl
  Titre Long-term changes in the breeding seasonality of Peruvian seabirds and regime shifts in the Northern Humboldt Current System Type Article scientifique
  Année 2018 Publication Revue Abrégée Mar. Ecol.-Prog. Ser.  
  Volume 597 Numéro Pages 231-242  
  Mots-Clés anchovy; climate-change; current ecosystem; cycles; Environmental cues; fishery; guano birds; impacts; nhcs; Northern Humboldt Current System; Onset of breeding; oscillation; Oxycline depth; Pelecanus thagus; Phalacrocorax bougainvillii; population-dynamics; sardine; Sula variegata  
  Résumé In the highly productive Northern Humboldt Current System, 3 seabird species, the Guanay cormorant Phalacrocorax bougainvillii, the Peruvian booby Sula variegata and the Peruvian pelican Pelecanus thagus, commence breeding in austral spring, coinciding with the lowest availability of their prey, the Peruvian anchovy Engraulis ringens. This strategy ensures the matching of increased prey availability when young achieve independence in summer. This pattern was observed during the last decade when anchovy was abundant. However, over the last century, the abundance of anchovy has varied widely due to contrasting interdecadal regimes in oceanographic conditions and fishing activity. We hypothesized that these regime shifts affected the abundance and availability of prey and may have conditioned the breeding seasonality of seabirds. We examined the timing and magnitude of the onset of breeding using dynamic occupancy models and related these parameters to the seasonality of oceanographic conditions, abundance of anchovy and fishing pressure. During a regime of lower anchovy abundance (1977-1990), cormorants showed the highest flexibility, adjusting the timing of breeding from spring to winter and skipping reproduction in the worst conditions. Boobies showed the lowest flexibility, maintaining the same magnitude and timing of onset of breeding in spring. Pelicans showed intermediate flexibility, foregoing breeding during the worst conditions, but maintaining the onset of breeding in spring. The 3 species used sea surface temperature as a cue for the initiation of breeding. Furthermore, given their better diving abilities, cormorants could monitor prey availability changes associated with the reversion in the seasonality of the oxycline depth.  
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  Auteur institutionnel Thèse  
  Editeur Lieu de Publication Éditeur  
  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0171-8630 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 2381  
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