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Registros recuperados: 43
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A dynamic model of the Bay of Biscay pelagic fleet simulating fishing trip choice: the response to the closure of the European anchovy (Engraulis encrasicolus) fishery in 2005 ArchiMer
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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A model-based evaluation of Marine Protected Areas: the example of eastern Baltic cod (Gadus morhua callarias L.) ArchiMer
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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Achieving maximum sustainable yield in mixed fisheries: a management approach for the North Sea demersal fisheries ArchiMer
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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Adult-mediated connectivity affects inferences on population dynamics and stock assessment of nursery-dependent fish populations ArchiMer
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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An autoregressive model to describe fishing vessel movement and activity ArchiMer
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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An investigation of human vs. technology-induced variation in catchability for a selection of European fishing fleets ArchiMer
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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Catch-quota balancing in mixed-fisheries: a bio-economic modelling approach applied to the New Zealand hoki (Macruronus novaezelandiae) fishery ArchiMer
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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Combining fleet dynamics and population dynamics for a volatile fishery: the example of the anchovy fishery of the Bay of Biscay ArchiMer
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...
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Ano: 2012 URL: http://archimer.ifremer.fr/doc/00107/21858/19449.pdf
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Combining multiple data sets to unravel the spatiotemporal dynamics of a data-limited fish stock ArchiMer
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...
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Ano: 2019 URL: https://archimer.ifremer.fr/doc/00460/57187/59150.pdf
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Compléments à la réponse à la saisine 2008-1014 sur les pressions potentielles des engins de pêche sur les habitats et espèces listés dans les Directives Habitats (92/43/EEC) et Oiseaux (2009/147/CE), pour les sennes danoises et écossaises ainsi qu’envers les récifs côtiers et les récifs circalittoraux. ArchiMer
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.
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Ano: 2016 URL: http://archimer.ifremer.fr/doc/00300/41147/41077.pdf
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Comportement de pêche et gestion : l’exemple de la pêcherie pélagique du Golfe de Gascogne ArchiMer
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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Description de l’activité des navires capturant le rouget barbet. Evolution des captures et des débarquements sur la période 2000-2011 ArchiMer
Mahe, Kelig; Vermard, Youen; Berthou, Patrick; Leblond, Samuel; Pitel-roudaut, Mathilde.
Tipo: Text
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00110/22163/19816.pdf
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Emergence of a new predator in the North Sea: evaluation of potential trophic impacts focused on hake, saithe, and Norway pout ArchiMer
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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Estimates of the mortality and the duration of the trans-Atlantic migration of European eel Anguilla anguilla leptocephali using a particle tracking model ArchiMer
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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Evaluating deepwater fisheries management strategies using a mixed-fisheries and spatially explicit modelling framework ArchiMer
Marchal, Paul; Vermard, Youen.
Wehave used in this study a spatially explicit bioeconomic modelling framework to evaluate management strategies, building in both datarich and data-limited harvest control rules (HCRs), for a mix of deepwater fleets and species, on which information is variable. The main focus was on blue ling (Molva dypterygia). For that species, both data-rich and data-limited HCRs were tested, while catch per unit effort (CPUE) was used either to tune stock assessments, or to directly trigger management action. There were only limited differences between the performances of both HCRs when blue ling biomass was initialized at the current level, but blue ling recovered more quickly with the data-rich HCR when its initial biomass was severely depleted. Both types of HCR...
Tipo: Text Palavras-chave: Bioeconomic model; Catch per unit effort; Fleet dynamics; Harvest control rules; Management strategy evaluation; Mixed fisheries.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00151/26229/24330.pdf
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Evaluation of the bioeconomic sustainability of multi-species multi-fleet fisheries under a wide range of policy options using ISIS-Fish ArchiMer
Pelletier, Dominique; Mahevas, Stephanie; Drouineau, Hilaire; Vermard, Youen; Thebaud, Olivier; Guyader, Olivier; Poussind, Benjamin.
In order to provide reliable scientific advice and support for fisheries management, it is necessary to evaluate the biological and economic sustainability of complex fisheries, such as multi-species multi-fleet fisheries. Existing policy-screening modelling tools are not fully suitable in this purpose due to either an over-simplified description of population dynamics, or due to the lack of consideration of economic aspects. In this paper, we present a package that enables quantitative bioeconomic assessment of management scenarios. Population dynamics is described through spatially- and seasonally-explicit models. Exploitation dynamics is characterized by several fishing activities with specific spatial and seasonal features, and practiced by several...
Tipo: Text Palavras-chave: Policy screening; Natural resource management; Fisheries dynamics; Bioeconomic model; Population dynamics; Complex systems; Simulation tool.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-6782.pdf
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Exploring habitat credits to manage the benthic impact in a mixed fishery ArchiMer
Batsleer, J.; Marchal, Paul; Vaz, Sandrine; Vermard, Youen; Rijnsdorp, A. D.; Poos, J. J..
The performance of a combined catch quota and habitat credit system was explored to manage the sustainable exploitation of a mix of demersal fish species and reduce the benthic impacts of bottom trawl fisheries using a dynamic state variable model approach. The model was parameterised for the Eastern English Channel demersal mixed fishery using otter trawls or dredges. Target species differed in their association with habitat types. Restricting catch quota for plaice and cod had a limited effect on benthic impact, except when reduced to very low values, forcing the vessels to stay in port. Quota management had a minimal influence on fishing behaviour and hence resulted in a minimal reduction of benthic impact. Habitat credits may reduce the benthic impacts...
Tipo: Text Palavras-chave: Fleet dynamics; Dynamic state variable modelling; TAC; Total allowable catch; Mixed fisheries; Eastern English Channel; Plaice; Cod.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00418/52997/53997.pdf
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Fishing for space: Fine-scale multi-sector maritime activities influence fisher location choice ArchiMer
Tidd, Alex N.; Vermard, Youen; Marchal, Paul; Pinnegar, John; Blanchard, Julia L.; Milner-gulland, E. J..
The European Union and other states are moving towards Ecosystem Based Fisheries Management to balance food production and security with wider ecosystem concerns. Fishing is only one of several sectors operating within the ocean environment, competing for renewable and non-renewable resources that overlap in a limited space. Other sectors include marine mining, energy generation, recreation, transport and conservation. Trade-offs of these competing sectors are already part of the process but attempts to detail how the seas are being utilised have been primarily based on compilations of data on human activity at large spatial scales. Advances including satellite and shipping automatic tracking enable investigation of factors influencing fishers' choice of...
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Ano: 2015 URL: http://archimer.ifremer.fr/doc/00254/36518/35064.pdf
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How do demersal fishing fleets interact with aggregate extraction in a congested sea? ArchiMer
Marchal, Paul; Desprez, Michel; Vermard, Youen; Tidd, Alex.
The effects of the aggregate extraction intensity and the distance to extraction sites on the distribution of fishing effort were investigated for a broad selection of French and English demersal fleets operating in the Eastern English Channel. The most prominent result was that most fleets fishing near to aggregate extraction sites were not deterred by extraction activities. The fishing effort of dredgers and potters could be greater adjacent to marine aggregates sites than elsewhere, and also positively correlated to extraction intensity with a lag of 0–9 months. The distribution of fishing effort of French netters remained consistent over the study period. However, it is of note that the fishing effort of netters has increased substantially in the...
Tipo: Text Palavras-chave: Spatial management; Spatial planning; Demersal fisheries; Aggregate extraction; Eastern English Channel.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00206/31763/30651.pdf
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How fast can the European eel (Anguilla anguilla) larvae cross the Atlantic Ocean? ArchiMer
Bonhommeau, Sylvain; Blanke, Bruno; Treguier, Anne-marie; Grima, Nicolas; Rivot, Etienne; Vermard, Youen; Greiner, Eric; Le Pape, Olivier.
The migration duration of European eel (Anguilla anguilla) larvae (leptocephali) from the spawning areas in the Sargasso Sea to the European continental shelf remains highly controversial, with estimates varying from 6 months to more than 2 yr. We estimated the fastest migration period and the shortest distance travelled by eel larvae by simulating Lagrangian particles released in the Sargasso Sea and by simulating a range of larval behaviours (fixed-depth drift, vertical diurnal migration and active-depth selection to maximize current velocity). This enabled us to compute (i) a passive drift speed, and (ii) a hypothetic swimming speed needed for European eel larvae to cross the Atlantic in 6 months (i.e., the migration duration estimated from otolith...
Tipo: Text Palavras-chave: Sargasso Sea; Migration duration; Leptocephali; Lagrangian modelling; Gulf Stream; Fractals; Anguilla.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-6865.pdf
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