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Registros recuperados: 105
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Manual of fisheries survey protocols. PELGAS surveys (PELagiques GAScogne) ArchiMer
Doray, Mathieu; Badts, Vincent; Masse, Jacques; Duhamel, Erwan; Huret, Martin; Doremus, Ghislain; Petitgas, Pierre.
The PELGAS sea cruises aim at monitoring the Bay of Biscay pelagic ecosystem, in order to provide scientific data for the implementing of an ecosystemic management of Biscay living ressources. The spatial and temporal dynamics of small pelagic fish populations are specifically monitored, with a focus on anchovy populations. The cruise hence takes place in spring, during anchovy spawning, to allow for the assessment of both eggs and adult stages. The PELGAS ecosystemic cruise aims at collecting data at each level of the Biscay trophic chain. Data are collected continuously along parallel transects covering the whole Bay of Biscay, in order to thoroughly characterize the horizontal and vertical structures of the pelagic ecosystem. Multibeam and...
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Ano: 2014 URL: http://archimer.ifremer.fr/doc/00191/30259/28714.pdf
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WGACEGG acoustic and egg-based survey products for monitoring anchovy and sardine populations in the European Atlantic area ecosystem ArchiMer
Doray, Mathieu; Angelico, Maria Manuel; Iglesias, Magdalena; Jimenez, Paz; Marques, Vitor; Ramos, Fernando; Rodriguez-climent, Silvia; Santos, Maria; Van Der Kooij, Jeroen; Petitgas, Pierre.
The Working Group on Acoustic and Egg Surveys (WGACEGG) coordinates the pelagic integrated surveys in ICES Areas 7, 8 and 9. Those surveys provide fisheries-independent, acoustic and/or egg-based estimates of the biomass and demographic structure of sardine and anchovy populations. Survey biomass estimates are the main inputs used to manage those commercially important small pelagic stocks in the European Atlantic area (EAA). Taking advantage of the fine spatial resolution of acoustic and egg data, and of ancillary ecosystem data provided by integrated pelagic surveys, WGACEGG also compile standard gridded maps of anchovy and sardine eggs and adult biomass, as well as maps of key in-situ hydrological parameters (surface salinity and temperature). We...
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Ano: 2018 URL: http://archimer.ifremer.fr/doc/00457/56841/58650.pdf
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Fifteen years of data from the PELGAS integrated survey (2000-2015): what have we learned on the Bay of Biscay pelagic ecosystem? ArchiMer
Doray, Mathieu; Petitgas, Pierre; Romagnan, Jean-baptiste; Huret, Martin; Duhamel, Erwan; Dupuy, Christine; Spitz, Jérôme; Authier, Matthieu; Berger, Laurent; Doremus, Ghislain; Bourriau, Paul; Grellier, Patrick; Masse, Jacques; Sanchez, Florence.
The initial focus of the PELGAS integrated survey was to assess the small pelagic fish biomass in the Bay of Biscay in springtime, for fisheries management purposes. Sampling has been extended to produce long-term time-series of spatially-explicit data and indices, describing the main pelagic ecosystem components: hydrology, phytoplankton, mesozooplankton, fish and megafauna. A collaborative analysis of these datasets has brought new insights on the Bay of Biscay pelagic ecosystem summarized here. New results on single ecosystem components include an analysis of water samples to groundtruth the results of an ocean color algorithm aiming at detecting phytoplanktonic coccolithophores. New insights on mesozooplankton spatio-temporal distribution and energy...
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Ano: 2018 URL: http://archimer.ifremer.fr/doc/00445/55665/57331.pdf
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Integrated understanding of initial conditions of early life stages using integrated ecosystem survey data ArchiMer
Petitgas, Pierre; Huret, Martin; Doray, Mathieu; Bourriau, Paul; Lunven, Michel.
Since 2000, the yearly acoustic pelagic survey of Ifremer in the Bay of Biscay designed for fish stock assessment of small pelagic fish has been converted into an integrated pelagic ecosystem monitoring plateforme. This has been achieved by coupling sensors and automating data acquisition streams. The data series now spans from 2000 to 2014. Together with data sensors and sampling designs, we present here an integrated study allowing to understand the spawning process of anchovy. We compare the maps of anchovy eggs obtained with CUFES (continuous underway fish egg sampler) with that of their spawning adults sampled at the same time by acoustics and identification trawl hauls. The distributions of eggs are surprisingly different than that of adults, with in...
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Ano: 2015 URL: http://archimer.ifremer.fr/doc/00281/39177/37738.pdf
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Combining sensitivity and uncertainty analysis to evaluate the impact of management measures with ISIS-Fish: marine protected areas for the Bay of Biscay anchovy (Engraulis encrasicolus) fishery ArchiMer
Lehuta, Sigrid; Mahevas, Stephanie; Petitgas, Pierre; Pelletier, Dominique.
Spatio-seasonal explicit simulation models can predict the impact of spatial management measures on marine fish populations and fishing activities. As fisheries are complex systems, fisheries simulation models are often complex, with many uncertain parameters. Here, the methodology is provided to deliver fishery diagnostics within an uncertainty context using a complex simulation tool. A sensitivity analysis of the model is performed on model outputs using partial least-squares to identify the most sensitive parameters. The impact of several management measures is then simulated using a statistical simulation design taking into account the uncertainty of the selected sensitive parameters. This approach was applied to the Bay of Biscay anchovy stock using...
Tipo: Text Palavras-chave: Bay of Biscay anchovy; Marine protected area; Sensitivity analysis; Simulation; Uncertainty analysis.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00011/12234/9281.pdf
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Monitoring small pelagic fish in the Bay of Biscay ecosystem, using indicators from an integrated survey ArchiMer
Doray, Mathieu; Petitgas, Pierre; Huret, Martin; Duhamel, Erwan; Romagnan, Jean-baptiste; Authier, Matthieu; Dupuy, Christine; Spitz, Jerome.
This paper is a practical contribution to two important debates raised by the implementation of marine ecosystem based management: (i) which ecosystem data can be provided by a fisheries survey optimised for ecosystem monitoring; and (ii) how to combine/select potential indicators to derive useful information on marine ecosystem status and dynamics? A suite of 143 potential indicators, including spatial indices, representing small pelagic fish and their biotic and abiotic environments are presented. Indicators were routinely derived from the PELGAS integrated ecosystem survey conducted in spring in the Bay of Biscay (BoB). The general patterns over time in this suite of 5–16 years, non-stationary time series are characterised using a methodology based on...
Tipo: Text Palavras-chave: Min/max autocorrelation factors; Time correlation; Survey-based indicators; Marine Strategy Framework Directive; Ecosystem variability; Bay of Biscay; Pelagic ecosystem.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00414/52552/53443.pdf
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Modeling fish growth and reproduction in the context of the Dynamic Energy Budget theory to predict environmental impact on anchovy spawning duration ArchiMer
Pecquerie, Laure; Petitgas, Pierre; Kooijman, Sebastiaan.
Spawning location and timing are critical for understanding fish larval survival. The impact of a changing environment on spawning patterns is, however, poorly understood. A novel approach is to consider the impact of the environment on individual life histories and subsequent spawnings. In the present work, we extend the Dynamic Energy Budget (DEB) theory to investigate how environment variability impacts the spawning timing and duration of a multiple-batch spawning species. The model is successfully applied to reproduce the growth and reproduction of anchovy (Engraulis encrasicolus) in the Bay of Biscay. The model captures realistically the start and ending of the spawning season, including the timing of the spawning events, and the change in egg number...
Tipo: Text Palavras-chave: Bay of Biscay; Engraulis encrasicolus; Starvation; Environmental conditions; Condition factor; Multiple Batch Spawning; Reproductive Biology; DEB Theory.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-6769.pdf
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Biophysical modelling of larval drift, growth and survival for the prediction of anchovy (Engraulis encrasicolus) recruitment in the Bay of Biscay (NE Atlantic) ArchiMer
Allain, Gwenhael; Petitgas, Pierre; Lazure, Pascal; Grellier, Patrick.
Fish recruitment is the result of the integration of small-scale processes affecting larval survival over a season and large oceanic areas. A hydrodynamic model was used to explore and model these physical-biological interaction mechanisms and then to perform the integration from individual to population scales in order to provide recruitment predictions for fisheries management. This method was applied to the case of anchovy (Engraulis encrasicolus) in the Bay of Biscay (NE Atlantic). The main data available to investigate survival mechanisms were past growth (otolith) records of larvae and juveniles sampled at sea. The drift history of these individuals was reconstructed by a backtracking procedure using hydrodynamic simulations. The relationships...
Tipo: Text Palavras-chave: Recruitment; Physical biological interactions; Individual based models; Biscay; Anchovy.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-3422.pdf
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Selection and validation of a complex fishery model using an uncertainty hierarchy ArchiMer
Lehuta, Sigrid; Petitgas, Pierre; Mahevas, Stephanie; Huret, Martin; Vermard, Youen; Uriarte, Andres; Record, Nicholas R..
Assessing the validity of a model is essential for its credibility especially when the model is used as decision making tool. Complex dynamic fishery models are recommended to investigate the functioning of fisheries and to assess the impact of management strategies, particularly spatial fishing regulations. However, their use is limited due to the difficulty and computational cost of parameterizing and gaining confidence, particularly for parameter rich models. These difficulties are compounded by uncertainty regarding parameter values, many of which are often taken from literature or estimated indirectly. Here we propose a methodology to improve confidence and understanding in the model, easily transferable to any complex model. The approach combines...
Tipo: Text Palavras-chave: Bay of Biscay anchovy; Dynamic fishery model; Model selection; Uncertainty; Validation.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00148/25965/24150.pdf
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Variation that can be expected when using particle tracking models in connectivity studies ArchiMer
Hufnagl, Marc; Payne, Mark; Lacroix, Genevieve; Bolle, Loes J.; Daewele, Ute; Dickey-collas, Mark; Gerkema, Theo; Huret, Martin; Janssen, Frank; Kreus, Markus; Paetsch, Johannes; Pohlmann, Thomas; Ruardij, Piet; Schrum, Corinna; Skogen, Morten D.; Tiessen, Meinard C. H.; Petitgas, Pierre; Van Beek, Jan K. L.; Van Der Veer, Henk W.; Callies, Ulrich.
Hydrodynamic Ocean Circulation Models and Lagrangian particle tracking models are valuable tools e.g. in coastal ecology to identify the connectivity between offshore spawning and coastal nursery areas of commercially important fish, for risk assessment and more for defining or evaluating marine protected areas. Most studies are based on only one model and do not provide levels of uncertainty. Here this uncertainty was addressed by applying a suite of 11 North Sea models to test what variability can be expected concerning connectivity. Different notional test cases were calculated related to three important and well-studied North Sea fish species: herring (Clupea harengus), and the flatfishes sole (Solea solea) and plaice (Pleuronectes platessa). For sole...
Tipo: Text Palavras-chave: Ocean circulation; Lagrangian approach; Variability; Marine protected areas; Renewable energy; Wind park; Model intercomparison; Ensemble.
Ano: 2017 URL: https://archimer.ifremer.fr/doc/00385/49660/50198.pdf
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Modélisation couplée physique-biogéochimie du golfe de Gascogne sur la période 1971-2007 ArchiMer
Huret, Martin; Struski, Caroline; Leger, Fabien; Petitgas, Pierre; Lazure, Pascal; Sourisseau, Marc.
Une simulation 'hindcast' de la dynamique physique et biogéochimique du golfe de Gascogne a été réalisée pour la période 1971-2007 à l'aide du modèle ECO-MARS3D. Ce modèle couplant physique et biogéochimie fournit une série longue de données simulées, moyennées ou intégrées sur 3 jours (température, salinité, sels nutritifs, phytoplancton, zooplancton), qui sont ensuite utilisées pour des calculs d'indices hydrologiques 2D synthétiques (indices méso-échelle : stratification, upwellings, surface tourbillonnaire ; indices biologiques : chlorophylle-a de surface, production primaire intégrée). Nous nous proposons dans ce document de présenter la configuration et les forçages utilisés pour cette simulation, et de lister les différentes variables sauvegardées...
Tipo: Text Palavras-chave: Projet FP6 RECLAIM; Halieutique; Indices hydrologiques; Hindcast; ECO MARS3D; Modélisation couplée; Golfe de Gascogne.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/rapport-5164.pdf
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Effects of spawning patterns and larval mortality on survival to the juvenile stage : a modelling analysis on the anchovy population of the Bay of Biscay ArchiMer
Huret, Martin; Petitgas, Pierre; Struski, Caroline.
Fish populations show complex life cycles with successive dependent life stages, the spatio-temporal patterns of distribution at one stage impacting distribution, growth and mortality during the next stage. Here we propose to assess the relative effect of spawning (timing, duration, fecundity and spatial distribution, resulting from adult environmental conditions over autumn and winter) and larval mortality on the resulting survival at the age of metamorphosis. We used a suite of models run sequentially : a coupled physical-biogeochemical model to provide the environmental forcing, a Dynamic Energy Budget (DEB) model for adult fish growth and reproduction (spawning timing, duration and fecundity), an Individual Based Model (IBM) for larval drift, growth...
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Ano: 2010 URL: http://archimer.ifremer.fr/doc/00023/13451/10464.pdf
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Lower trophic levels and detrital biomass control the Bay of Biscay continental shelf food web: Implications for ecosystem management ArchiMer
Lassalle, G.; Lobry, J.; Le Loc'H, F.; Bustamante, Paco; Certain, Gregoire; Delmas, Daniel; Dupuy, C.; Hily, Christian; Labry, Claire; Le Pape, O.; Marquis, Elise; Petitgas, Pierre; Pusineri, Claire; Ridoux, Vincent; Spitz, J.; Niquil, Nathalie.
The Bay of Biscay (North-East Atlantic) has long been subjected to intense direct and indirect human activities that lead to the excessive degradation and sometimes overexploitation of natural resources. Fisheries management is gradually moving away from single-species assessments to more holistic, multi-species approaches that better respond to the reality of ecosystem processes. Quantitative modelling methods such as Ecopath with Ecosim can be useful tools for planning, implementing and evaluating ecosystem-based fisheries management strategies. The aim of this study was therefore to model the energy fluxes within the food web of this highly pressured ecosystem and to extract practical information required in the diagnosis of ecosystem state/health. A...
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Ano: 2011 URL: http://archimer.ifremer.fr/doc/00057/16851/14329.pdf
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One-dimensional biophysical modelling of fish egg vertical distributions in shelf seas ArchiMer
Petitgas, Pierre; Magri Hoeltzener, Stephanie; Lazure, Pascal.
Modelling the vertical distribution of fish eggs is important when assessing fish stocks with egg production methods and for monitoring the reproductive potential of fish populations. Fish eggs are passive particles and their vertical distribution is determined by a few parameters such as egg density, egg diameter, wind- and tide-induced turbulence, and vertical hydrographic structure. A one-dimensional vertical biophysical, numerical model was developed which was adapted to the hydrography of shelf seas under the influence of tidal currents, wind-induced circulation, and river discharges. The biological part of the model parameterized the ascent velocity of the egg as a function of egg properties (diameter, density) and water properties (density,...
Tipo: Text Palavras-chave: Vertical distribution; Sprat; Sardine; Fish egg buoyancy; CUFES; Biophysical coupling; Anchovy.
Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/publication-2277.pdf
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Stock collapses and their recovery: mechanisms that establish and maintain life-cycle closure in space and time ArchiMer
Petitgas, Pierre; Secor, Dave H.; Mcquinn, Ian; Huse, Geir; Lo, Nancy.
Experience has established that the recovery of many collapsed stocks takes much longer than predicted by traditional fishery population models. We put forward the hypothesis that stock collapse is associated with disruption of the biological mechanisms that sustain life-cycle closure of intrapopulation contingents. Based on a review of case studies of nine marine fish stocks, we argue that stock collapses not only involve biomass loss, but also the loss of structural elements related to life-cycle diversity (contingents), as well as the breakdown of socially transmitted traditions (through a curtailed age range). Behavioural mechanisms associated with these structural elements could facilitate recovery of depleted populations. Migratory behaviour is...
Tipo: Text Palavras-chave: Behaviour; Collapse; Life-cycle diversity; Recovery.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00021/13186/10262.pdf
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Use of satellite image products to understand variation in fish length: Anchovy in the Bay of Biscay ArchiMer
Petitgas, Pierre; Gohin, Francis; Duhamel, Erwan; Doray, Mathieu; Schmidt, Jörn; Voss, Rudiger.
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Ano: 2019 URL: https://archimer.ifremer.fr/doc/00590/70202/68229.pdf
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Populations ichtyologiques de petits pélagiques. Sous-région marine Mers celtiques. Evaluation initiale DCSMM. ArchiMer
Petitgas, Pierre; Massé, Jacques; Huret, Martin; Doray, Mathieu; Duhamel, Erwan.
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Ano: 2012 URL: https://archimer.ifremer.fr/doc/00328/43948/43521.pdf
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Impacts of climate change on the complex life cycles of fish ArchiMer
Petitgas, Pierre; Rijnsdorp, Adriaan D.; Dickey-collas, Mark; Engelhard, Georg H.; Peck, Myron A.; Pinnegar, John; Drinkwater, Kenneth F.; Huret, Martin; Nash, Richard.
To anticipate the response of fish populations to climate change, we developed a framework that integrates requirements in all life stages to assess impacts across the entire life cycle. The framework was applied on plaice (Pleuronectes platessa) and Atlantic herring (Clupea harengus) in the North Sea, Atlantic cod (Gadus morhua) in the Norwegian/Barents Seas and European anchovy (Engraulis encrasicolus) in the Bay of Biscay. In each case study, we reviewed habitats required by each life stage, habitat availability, and connectivity between habitats. We then explored how these could be altered by climate change. We documented environmental processes impacting habitat availability and connectivity, providing an integrated view at the population level and in...
Tipo: Text Palavras-chave: Connectivity; Habitat; Eco-physiology; Anchovy; Herring; Plaice; Cod.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00118/22935/20798.pdf
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A Geostatistical Definition of Hotspots for Fish Spatial Distributions ArchiMer
Petitgas, Pierre; Woillez, Mathieu; Doray, Mathieu; Rivoirard, Jacques.
Research surveys at sea are undertaken yearly to monitor the distribution and abundance of fish stocks. In the survey data, a small number of high fish concentration values are often encountered, which denote hotspots of interest. But statistically, they are responsible for important uncertainty in the estimation. Thus understanding their spatial predictability given their surroundings is expected to reduce such uncertainty. Indicator variograms and cross-variograms allow to understand the spatial relationship between values above a cutoff and the rest of the distribution under that cutoff. Using these tools, a “top” cutoff can be evidenced above which values are spatially uncorrelated with their lower surroundings. Spatially, the geometric set...
Tipo: Text Palavras-chave: Hotspots; Indicators; Non-linear geostatistics; Multivariate geostatistics; Anchovy; Biscay.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00273/38380/36734.pdf
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Use of a disjunctive kriging to model areas of high pelagic fish density in acoustic fisheries surveys ArchiMer
Petitgas, Pierre.
Schooling fish may aggregate in very high densities covering very small areas. Thus the probability of hitting such high-density spots during a large-scale sampling is very low. The sampling fluctuations of the tail of the histogram are thought to be very significant. The stock biomass estimate and its precision rely greatly on how precisely the tail of the histogram can be sampled. In order to acquire elements for improving survey designs and abundance estimators wc study here the relation in space that the high values have with the other values. A disjunctive kriging approach is used. Different quantiles of the histogram are coded by indicators. The spatial structure of each indicator and its spatial covariation with the others are studied by computing...
Tipo: Text Palavras-chave: Distribution spatiale; Agrégation; Abondance; Estimation; Géostatistique; Échantillonnage; Spatial distribution; Aggregation; Abundance estimation; Geostatistics; Sampling.
Ano: 1993 URL: http://archimer.ifremer.fr/doc/00190/30076/28564.pdf
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