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| Registros recuperados: 51 | |
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| Vermard, Youen; Marchal, Paul; Mahevas, Stephanie; Thebaud, Olivier. |
| The scope of this paper is to describe, evaluate, and forecast fishing trip choices of the Bay of Biscay pelagic fleet using random utility modeling (RUM). First, alternative fishing trip choices of this fleet were identified using multivariate statistical methods based on species landings weighted by value and defined as distinct fishing activity or fisheries (termed metiers). A RUM was specified, which included trip components as attributes during the period 20012004 ( a lagged percentage of the value per unit of effort of the main species caught, total value per unit of effort, and inertia in terms of changes from one metier to another). For the main metiers, the proportion of correct effort allocation is 90% during the calibration period of 2001-2004.... |
| Tipo: Text |
Palavras-chave: Management; Métier; Fishing effort; Fisher's behavior; RUM. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6096.pdf |
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| Kraus, Gerd; Pelletier, Dominique; Dubreuil, Julien; Moellmann, Christian; Hinrichsen, Hans-harald; Bastardie, Francois; Vermard, Youen; Mahevas, Stephanie. |
| The eastern Baltic cod stock collapsed as a consequence of climate-driven adverse hydrographic conditions and over fishing and has remained at historically low levels. Spatio-temporal fishing closures [Marine Protected Areas (MPAs)] have been implemented since 1995, to protect and restore the spawning stock. However, no signs of recovery have been observed yet, either suggesting that MPAs are an inappropriate management measure or pointing towards suboptimal closure design. We used the spatially explicit fishery simulation model ISIS-Fish to evaluate proposed and implemented fishery closures, combining an age-structured population module with a multifleet exploitation module and a management module in a single model environment. The model is parameterized... |
| Tipo: Text |
Palavras-chave: Stock recovery; Model; Marine Protected Areas; Fishery management; Baltic cod. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6094.pdf |
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| Ulrich, Clara; Vermard, Youen; Dolder, Paul J.; Brunel, Thomas; Jardim, Ernesto; Holmes, Steven J.; Kempf, Alexander; Mortensen, Lars O.; Poos, Jan-jaap; Rindorf, Anna. |
| Achieving single species maximum sustainable yield (MSY) in complex and dynamic fisheries targeting multiple species (mixed fisheries) is challenging because achieving the objective for one species may mean missing the objective for another. The North Sea mixed fisheries are a representative example of an issue that is generic across most demersal fisheries worldwide, with the diversity of species and fisheries inducing numerous biological and technical interactions. Building on a rich knowledge base for the understanding and quantification of these interactions, new approaches have emerged. Recent paths towards operationalizing MSY at the regional scale have suggested the expansion of the concept into a desirable area of “pretty good yield”, implemented... |
| Tipo: Text |
Palavras-chave: Choke species; Common Fisheries Policy; Fleet modelling; FMSY ranges; Landing obligation; Management plan; Pretty good yield. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00347/45834/45922.pdf |
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| Archarnbault, Benoit; Le Pape, Olivier; Baulier, Loic; Vermard, Youen; Veron, Matthieu; Rivot, Etienne. |
| We explore how alternative hypotheses on the degree of mixing among local subpopulations affect statistical inferences on the dynamics and stock assessment of a harvested flatfish population, namely, the common sole population in the Eastern Channel (ICES area VIId). The current paradigm considers a single, well-mixed, spatially homogeneous population with juveniles from all coastal nursery grounds along the French and UK coasts that contribute to a single adult population and one pool of eggs. Based on the available data and ecological knowledge, we developed a spatial Bayesian integrated life-cycle model that consists of three subpopulations (one near the UK coast and two near the French coast, denoted UK, West FR and East FR, respectively) supported by... |
| Tipo: Text |
Palavras-chave: Solea solea; Spatial life-cycle model; Coastal nurseries; Connectivity; Stock assessment; Hierarchical bayesian model. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00333/44430/44231.pdf |
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| Gloaguen, Pierre; Mahevas, Stephanie; Rivot, Etienne; Woillez, Mathieu; Guitton, Jerome; Vermard, Youen; Etienne, Marie-pierre. |
| The understanding of the dynamics of fishing vessels is of great interest to characterize the spatial distribution of the fishing effort and to define sustainable fishing strategies. It is also a prerequisite for anticipating changes in fishermen's activity in reaction to management rules, economic context, or evolution of exploited resources. Analyzing the trajectories of individual vessels offers promising perspectives to describe the activity during fishing trips. A hidden Markov model with two behavioral states (steaming and fishing) is developed to infer the sequence of non-observed fishing vessel behavior along the vessel trajectory based on Global Positioning System (GPS) records. Conditionally to the behavior, vessel velocity is modeled with an... |
| Tipo: Text |
Palavras-chave: Hidden Markov model; Vessels dynamics; RECOPESCA; Autoregressive process; Baum-Welch algorithm. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00179/29049/27485.pdf |
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| Mahevas, Stephanie; Vermard, Youen; Hutton, Trevor; Iriondo, Ane; Jadaud, Angelique; Maravelias, Christos D.; Punzon, Antonio; Sacchi, Jacques; Tidd, Alex; Tsitsika, Efthymia; Marchal, Paul; Goascoz, Nicolas; Mortreux, Serge; Roos, David. |
| The impact of the fishing effort exerted by a vessel on a population depends on catchability, which depends on population accessibility and fishing power. The work investigated whether the variation in fishing power could be the result of the technical characteristics of a vessel and/or its gear or whether it is a reflection of inter-vessel differences not accounted for by the technical attributes. These inter-vessel differences could be indicative of a skipper/crew experience effect. To improve understanding of the relationships, landings per unit effort (lpue) from logbooks and technical information on vessels and gears (collected during interviews) were used to identify variables that explained variations in fishing power. The analysis was undertaken by... |
| Tipo: Text |
Palavras-chave: Catchability; Fishing power; GAM; GLM; Skipper skill; Technical characteristics. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00049/16043/15172.pdf |
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| Marchal, Paul; Francis, Chris; Lallemand, Philippe; Lehuta, Sigrid; Mahevas, Stephanie; Stokes, Kevin; Vermard, Youen. |
| Managing adequately the exploitation of commercial species subject to technical interactions is a key step towards the ecosystem approach to fisheries. We evaluate here, using a bio-economic modelling approach building on the ISIS-Fish simulation platform, the relative impact of total allowable commercial catches (TACC) and of taxes applicable to over-quota landings (deemed value) on the sustainability of a selection of species exploited by the New Zealand hoki (Macruronus novaezelandiae) fishery. We investigate some aspects of the hoki mixed fisheries, consisting of four fleets and nineteen metiers, by considering the technical interactions between hoki and Southern hake (Merluccius australis). The dynamics of effort allocation were modelled using gravity... |
| Tipo: Text |
Palavras-chave: Fleet dynamics; New Zealand hoki fishery; Deemed value; Fisheries management. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00000/11168/7521.pdf |
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| Vermard, Youen; Lehuta, Sigrid; Mahevas, Stephanie; Thebaud, Olivier; Marchal, Paul; Gascuel, Didier. |
| It is increasingly recognized that fisher‟s behavior should be taken into account to understand and predict fishery dynamics, in particular in response to management. ISIS-Fish is a spatially and seasonally explicit modeling framework especially designed to couple populations and fleets dynamics and explore the impact of various management measures on mixed fisheries. It has already been set up using a static fishing effort allocation (corresponding to an average historical pattern) between the various métiers to simulate the pelagic fishery in the Bay of Biscay. We present here the integration of a fleet dynamics model. This model is derived from a Random Utility Model simulating métiers choice using as explanatory variables the past value per unit... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00107/21858/19449.pdf |
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| Pinto, Cecilia; Travers-trolet, Morgane; Macdonald, Jed; Rivot, Etienne; Vermard, Youen. |
| The biological status of many commercially-exploited fishes remains unknown, mostly due to a lack of data necessary for their assessment. Investigating the spatio-temporal dynamics of such species can lead to new insights into population processes, and foster a path towards improved spatial management decisions. Here, we focused on striped red mullet (Mullus surmuletus), a widespread, yet data-limited species of high commercial importance. Aiming to quantify range dynamics in this data-poor scenario, we combined fishery-dependent and -independent datasets through a series of Bayesian mixed-effects models designed to capture monthly and seasonal occurrence patterns near the species’ northern range limit across 20 years. Combining multiple datasets allowed... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00460/57187/59150.pdf |
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| Biseau, Alain; Le Mao, Patrick; Sartoretto, Stephane; Tourolle, Julie; Menot, Lenaick; Fabri, Marie-claire; Larnaud, Pascal; Drogou, Mickael; Morandeau, Fabien; Vacherot, Jean-philippe; Vermard, Youen. |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00300/41147/41077.pdf |
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| Vermard, Youen. |
| In the current context of fisheries management, simulation models are required to support the evaluation of management scenarios. These models should include the key processes of the fishery system: stock dynamics, fleet dynamics, manager decision-making, and the interactions between these three elements. Most of the existing models have concentrated on the modeling of biological processes, population dynamics, and ecosystem interactions. However, a number of fisheries management failures could have resulted from a misunderstanding of fishers behavior rather than from limited knowledge of the status of fishery resources. It has for example been showed that in an exploited system, fishers’ spatial behavior influences the predicted outcomes of management... |
| Tipo: Text |
Palavras-chave: Dynamique de flottille; RUM; VMS; Évaluation de mesures de gestion; Fleet dynamics; Random Utility Model; VMS; Management strategy evaluation. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00001/11256/7799.pdf |
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| Cormon, Xochitl; Kempf, Alexander; Vermard, Youen; Vinther, Morten; Marchal, Paul. |
| During the last 15 years, northern European hake (Merluccius merluccius) has increased in abundance, and its spatial distribution has expanded in the North Sea region in correlation with temperature. In a context of global warming, this spatial shift could impact local trophic interactions: direct impacts may affect forage fish through modified predator–prey interactions, and indirect impacts may materialize through competition with other resident predators. For instance, North Sea saithe (Pollachius virens) spatial overlap with hake has increased while saithe spawning-stock biomass has decreased recently notwithstanding a sustainable exploitation. In this context, we investigated the range of potential impacts resulting from most recent hake emergence in... |
| Tipo: Text |
Palavras-chave: Hake; Interspecific competition; Maximum sustainable yield; Multispecies stock assessment; Norway pout; Predator-prey interactions; Saithe; Simple foodweb; SMS. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00327/43794/45917.pdf |
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| Bonhommeau, Sylvain; Le Pape, O.; Gascuel, D.; Blanke, Bruno; Treguier, Anne-marie; Grima, Nicolas; Vermard, Youen; Castonguay, M.; Rivot, E.. |
| Using Lagrangian simulations, based on circulation models over three different hydroclimatic periods in the last 45 years in the North Atlantic Ocean, the trans-Atlantic migration of the European eel Anguilla anguilla leptocephali was simulated via the passive drift of particles released in the spawning area. Three different behaviours were modelled: drifting at fixed depth, undergoing a vertical migration or choosing the fastest currents. Simulations included mortality hypotheses to estimate a realistic mean migration duration and relative survival of A. anguilla larvae. The mean migration duration was estimated as 21 months and the mortality rate as 3 center dot 8 per year, i.e. < 0 center dot 2% of A. anguilla larvae may typically survive the... |
| Tipo: Text |
Palavras-chave: Migration duration; Leptocephalus mortality; Lagrangian modelling. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6614.pdf |
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| Vigneau, Joel; Biseau, Alain; Cochard, Marie-laure; Vermard, Youen. |
| Expression de la demande : La demande d’avis de la part de la Direction Interrégionale de la mer Manche Est – mer du Nord (DIRM-MMN) datant du 25 février 2015 et référencée 25/2015 est présentée en annexe. La demande fait référence à un arrêté d’interdiction faite à une liste d’engins traînants de fond dans les zones de nourricerie en Baie de Seine afin de favoriser la reconstitution des stocks de sole. La liste des engins prohibés (annexe III de l’arrêté) inclut les dragues remorquées par bateau, code DRB selon la nomenclature FAO. Le comité régional des pêches de Basse-Normandie (CRPBN) s’inquiète de cette interdiction, arguant du fait que la zone protégée en baie de Seine occidentale englobe une partie des gisements mouliers de Grandcamp et Ravenoville,... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00255/36625/79503.pdf |
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| Biseau, Alain; Lissardy, Muriel; Marre, Guilhem; Daures, Fabienne; Macher, Claire; Merzereaud, Mathieu; Le Grand, Christelle; Gourguet, Sophie; Berthou, Patrick; Lehuta, Sigrid; Vermard, Youen; Savina-rolland, Marie. |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00299/41034/79172.pdf |
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| Vermard, Youen; Lehuta, Sigrid; Savina-rolland, Marie; Biseau, Alain. |
| La DPMA sollicite l’Ifremer pour déterminer la réduction de la mortalité par pêche nécessaire pour l’atteinte de l’objectif du Rendement Maximum Durable (RMD) entre 2015 et 2020, avec l’estimation des Totaux Admissibles de Capture (TAC) pour chaque année. La DPMA souhaite également faire appel à l’expertise de votre Institut pour évaluer les mesures de gestion proposées ci-après par une estimation de la réduction de la mortalité par pêche, ou par une estimation des impacts potentiels, en cas de données insuffisantes : - Limitation de l’effort de pêche par flottille par une réduction du nombre de jour de pêche. Une répartition par flottille et par mois de la mortalité par pêche est nécessaire pour déterminer s’il existe une saisonnalité sur cette pêcherie,... |
| Tipo: Text |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00228/33960/32299.pdf |
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| Registros recuperados: 51 | |
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