Consulta: creatorFacets:"Vermard, Youen"
Registros recuperados: 51
Data/hora: 08/06/2024 15:34:44

How fast can the European eel (Anguilla anguilla) larvae cross the Atlantic Ocean?
Provedor de dados: 5
Autores: 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

Evaluation de l’impact de la drague à moules sur la sole commune et son renouvellement dans les zones de nourricerie
Provedor de dados: 5
Autores: 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
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00255/36625/79503.pdf

Integrated ecological-economic fisheries models-Evaluation, review and challenges for implementation
Provedor de dados: 5
Autores: Nielsen, J. Rasmus; Thunberg, Eric; Holland, Daniel S.; Schmidt, Jorn O.; Fulton, Elizabeth A.; Bastardie, Francois; Punt, Andre E.; Allen, Icarus; Bartelings, Heleen; Bertignac, Michel; Bethke, Eckhard; Bossier, Sieme; Buckworth, Rik; Carpenter, Griffin; Christensen, Asbjorn; Christensen, Villy; Da-rocha, Jose M.; Deng, Roy; Dichmont, Catherine; Doering, Ralf; Esteban, Aniol; Fernandes, Jose A.; Frost, Hans; Garcia, Dorleta; Gasche, Loic; Gascuel, Didier; Gourguet, Sophie; Groeneveld, Rolf A.; Guillen, Jordi; Guyader, Olivier; Hamon, Katell; Hoff, Ayoe; Horbowy, Jan; Hutton, Trevor; Lehuta, Sigrid; Little, L. Richard; Lleonart, Jordi; Macher, Claire; Mackinson, Steven; Mahevas, Stephanie; Marchal, Paul; Mato-amboage, Rosa; Mapstone, Bruce; Maynou, Francesc; Merzereaud, Mathieu; Palacz, Artur; Pascoe, Sean; Paulrud, Anton; Plaganyi, Eva; Prellezo, Raul; Van Putten, Elizabeth I.; Quaas, Martin; Ravn-jonsen, Lars; Sanchez, Sonia; Simons, Sarah; Thebaud, Olivier; Tomczak, Maciej T.; Ulrich, Clara; Van Dijk, Diana; Vermard, Youen; Voss, Rudi; Waldo, Staffan.
Marine ecosystems evolve under many interconnected and area-specific pressures. To fulfil society's intensifying and diversifying needs while ensuring ecologically sustainable development, more effective marine spatial planning and broader-scope management of marine resources is necessary. Integrated ecological–economic fisheries models (IEEFMs) of marine systems are needed to evaluate impacts and sustainability of potential management actions and understand, and anticipate ecological, economic and social dynamics at a range of scales from local to national and regional. To make these models most effective, it is important to determine how model characteristics and methods of communicating results influence the model implementation, the nature of the...
Tipo: Text
Palavras-chave: Bio-economic models; Comparative model evaluation; Fisheries management advice; Integrated ecological-economic fisheries models; Marine spatial planning and cross-sector management; Performance criteria and scales and risks; Use and acceptance and implementation and communication and flexibility and complexity.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00391/50269/50898.pdf

Estimates of the mortality and the duration of the trans-Atlantic migration of European eel Anguilla anguilla leptocephali using a particle tracking model
Provedor de dados: 5
Autores: 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. &lt; 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

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.
Provedor de dados: 5
Autores: 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
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00300/41147/41077.pdf

Evaluation of the bioeconomic sustainability of multi-species multi-fleet fisheries under a wide range of policy options using ISIS-Fish
Provedor de dados: 5
Autores: 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

Solutions for ecosystem-level protection of ocean systems under climate change
Provedor de dados: 5
Autores: Queiros, Ana M.; Huebert, Klaus B.; Keyl, Friedemann; Fernandes, Jose A.; Stolte, Willem; Maar, Marie; Kay, Susan; Jones, Miranda C.; Hamon, Katell; Hendriksen, Gerrit; Vermard, Youen; Marchal, Paul; Teal, Lorna R.; Somerfield, Paul J.; Austen, Melanie C.; Barange, Manuel; Sell, Anne F.; Allen, Icarus; Peck, Myron A.
The Paris Conference of Parties (COP21) agreement renewed momentum for action against climate change, creating the space for solutions for conservation of the ocean addressing two of its largest threats: climate change and ocean acidification (CCOA). Recent arguments that ocean policies disregard a mature conservation research field and that protected areas cannot address climate change may be oversimplistic at this time when dynamic solutions for the management of changing oceans are needed. We propose a novel approach, based on spatial meta-analysis of climate impact models, to improve the positioning of marine protected areas to limit CCOA impacts. We do this by estimating the vulnerability of ocean ecosystems to CCOA in a spatially explicit manner and...
Tipo: Text
Palavras-chave: Climate change; Conservation; COP21; Ecosystem model; Habitat; Marine spatial planning; Ocean; Ocean acidification; Species distribution; Warming.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00360/47089/48566.pdf

Is speed through water a better proxy for fishing activities than speed over ground?
Provedor de dados: 5
Autores: Gloaguen, Pierre; Woillez, Mathieu; Mahevas, Stephanie; Vermard, Youen; Rivot, Etienne.
Understanding fishing vessel dynamics at a fine spatial scale is of great interest for defining appropriate spatial management plans. Different models have been developed to detect fishing activity from Vessel Monitoring System (VMS) data. While mathematical and statistical methods differ, all rely on the idea that vessel speed over ground provides information on fishing vessel activity. However, trawling with constant speed relative to the water mass may as well prove a winning strategy for both technical (to ensure sufficient trawl opening) and biological (to limit escapement of fish) reasons. Therefore, considering speed through water instead of speed over ground might provide insights into fishing activities. We developed a method combining surface...
Tipo: Text
Palavras-chave: Vessel monitoring system surface currents hidden Markov models; MARS 3D; Obsmer.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00359/47030/46948.pdf

Investigating spatial heterogeneity of von Bertalanffy growth parameters to inform the stock structuration of common sole, Solea solea, in the Eastern English Channel
Provedor de dados: 5
Autores: Du Pontavice, Hubert; Randon, Marine; Lehuta, Sigrid; Vermard, Youen; Savina-rolland, Marie.
In fisheries science, a mismatch between the delineation of a fish stock and the underlying biological population can lead to inaccurate assessment and management. Previous results suggested a potential spatial structuration of the Eastern English Channel (EEC) stock of common sole, Solea solea, in three sub-populations. In this article, we propose to investigate the spatial population structure of common sole in the EEC using the von Bertalanffy Growth Function parameters as indicators of population segregation. In order to test the sub-population hypothesis and evaluate its robustness to data sources, we developed three models, all including an area effect on growth parameters. The first model was aimed at testing a potential data source effect (in...
Tipo: Text
Palavras-chave: Key-words; Von Bertalanffy growth function; Stock structuration; Solea solea; Flatfish; Life-history traits; Metapopulation.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00445/55625/57301.pdf

An autoregressive model to describe fishing vessel movement and activity
Provedor de dados: 5
Autores: 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

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
Provedor de dados: 5
Autores: 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

Fishing for space: Fine-scale multi-sector maritime activities influence fisher location choice
Provedor de dados: 5
Autores: 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...
Tipo: Text
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00254/36518/35064.pdf

Analyse des interactions senneurs-chalutiers en Manche Est à micro-échelle.
Provedor de dados: 5
Autores: Vermard, Youen; Demaneche, Sebastien.
Tipo: Text
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00132/24373/22383.pdf

Improving the interpretation of fishing effort and pressures in mixed fisheries using spatial overlap metrics
Provedor de dados: 5
Autores: Bourdaud, Pierre; Travers-trolet, Morgane; Vermard, Youen; Marchal, Paul.
Managing mixed fisheries requires understanding fishers’ behaviour to allow predicting future fisheries distribution and impact on marine ecosystems. A new approach was developed to compare fine scale fishing effort distribution of Eastern English Channel (EEC) bottom trawlers, to the monthly- and spatially-resolved abundance distributions of commercial species. First, the added-value of using species-specific spatial overlap metric to quantify effective fishing effort and improve the relationship between fishing effort and fishing mortality was assessed. Second, based on the Ideal Free Distribution (IFD) theory, the species-specific weights given by fishers to different species were estimated by maximizing the overlap between target species assemblage and...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00446/55747/57402.pdf

Mixed fisheries management: protecting the weakest link
Provedor de dados: 5
Autores: Batsleer, Jurgen; Poos, J. J.; Marchal, Paul; Vermard, Youen; Rijnsdorp, A. D.
North Sea cod Gadus morhua stock is outside safe biological limits, and total allowable catch (TAC) management has proved ineffective to rebuild the stock. The European Commission is considering the imposition of a discard ban to preserve vulnerable and economically important fish stocks. We explored the potential effects of a discard ban in mixed fisheries management using the French mixed fisheries in the Eastern English Channel as a model system. We examined in particular the performance of 2 different management scenarios: (1) individual quota management with a tolerance for discarding and (2) individual quota management in combination with a discard ban, using a dynamic state variable model. The model evaluates a time series of decisions taken by...
Tipo: Text
Palavras-chave: Discard ban; TAC; Dynamic State Variable Modelling; Eastern English Channel; Cod; Gadus morhua; Mixed fisheries; Fleet dynamics.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00137/24781/22834.pdf

Selection and validation of a complex fishery model using an uncertainty hierarchy
Provedor de dados: 5
Autores: 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

Predicting fisher response to competition for space and resources in a mixed demersal fishery
Provedor de dados: 5
Autores: Girardin, Raphael; Vermard, Youen; Thebaud, Olivier; Tidd, Alex; Marchal, Paul.
Understanding and modelling fleet dynamics and their response to spatial constraints is a prerequisite to anticipating the performance of marine ecosystem management plans. A major challenge for fisheries managers is to be able to anticipate how fishing effort is re-allocated following any permanent or seasonal closure of fishing grounds, given the competition for space with other active maritime sectors. In this study, a Random Utility Model (RUM) was applied to determine how fishing effort is allocated spatially and temporally by the French demersal mixed fleet fishing in the Eastern English Channel. The explanatory variables chosen were past effort i.e. experience or habit, previous catch to represent previous success, % of area occupied by spatial...
Tipo: Text
Palavras-chave: Effort allocation; Random Utility Model; Spatial competition; Demersal mixed fishery; Eastern English Channel; Spatial management.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00250/36153/37312.pdf

North Sea saithe Pollachius virens growth in relation to food availability, density dependence and temperature
Provedor de dados: 5
Autores: Cormon, Xochitl; Ernande, Bruno; Kempf, Alexander; Vermard, Youen; Marchal, Paul.
North Sea saithe Pollachius virens, a major top predator in the area, supports the fishery economy of several European countries. However, recent stock assessments suggested a decrease in spawning stock biomass along with a decline in saithe mean weight-at-ages. In this context, we investigated North Sea saithe growth characteristics at the population level. First, saithe annual weight increments and age-length relationships were studied. Modelling of saithe age-length relationships was carried out using (1) the traditional von Bertalanffy growth function model, (2) the Verhulst logistic model and (3) an empirical linear model. Second, the effects of environmental factors on saithe growth were investigated. Explanatory environmental factors included food...
Tipo: Text
Palavras-chave: Bottom-up processes; Von Bertalanffy growth function; Logistic growth; Norway pout; Prey availability effects; Density-dependence; Predator-prey interactions; Resource limitation; Competition.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00314/42499/41875.pdf

Spatial interactions between saithe (Pollachius virens) and hake (Merluccius merluccius) in the North Sea
Provedor de dados: 5
Autores: Cormon, Xochitl; Loots, Christophe; Vaz, Sandrine; Vermard, Youen; Marchal, Paul.
Spatial interactions between saithe (Pollachius virens) and hake (Merluccius merluccius) were investigated in the North Sea. Saithe is a well-established species in the North Sea, while occurrence of the less common hake has recently increased in the area. Spatial dynamics of these two species and their potential spatial interactions were explored using binomial generalized linear models (GLM) applied to the International Bottom Trawl Survey (IBTS) data from 1991 to 2012. Models included different types of variables: (i) abiotic variables including sediment types, temperature, and bathymetry; (ii) biotic variables including potential competitors and potential preys presence; and (iii) spatial variables. The models were reduced and used to predict and map...
Tipo: Text
Palavras-chave: Biotic interactions; Competition; Generalized linear models; Hake; North Sea; Overlap; Predator-prey relationship; Saithe; Species distribution modelling.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00200/31146/29847.pdf

Identifying fishing trip behaviour and estimating fishing effort from VMS data using Bayesian Hidden Markov Models
Provedor de dados: 5
Autores: Vermard, Youen; Rivot, Etienne; Mahevas, Stephanie; Marchal, Paul; Gascuel, Didier.
Recent advances in technologies have lead to a vast influx of data on movements, based on discrete recorded position of animals or fishing boats, opening new horizons for future analyses. However, most of the potential interest of tracking data depends on the ability to develop suitable modelling strategies to analyze trajectories from discrete recorded positions. A serious modelling challenge is to infer the evolution of the true position and the associated spatio-temporal distribution of behavioural states using discrete, error-prone and incomplete observations. In this paper, a Bayesian Hierarchical Model (HBM) using Hidden Markov Process (HMP) is proposed as a template for analyzing fishing boats trajectories based on data available from...
Tipo: Text
Palavras-chave: Bayesian Hierarchical Models; Hidden Markov Model; State-space model; VMS; Fleet behaviour; Fishing effort.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00009/11993/9342.pdf

Emergence of a new predator in the North Sea: evaluation of potential trophic impacts focused on hake, saithe, and Norway pout
Provedor de dados: 5
Autores: 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

Identification of the main processes underlying ecosystem functioning in the Eastern English Channel, with a focus on flatfish species, as revealed through the application of the Atlantis end-to-end model
Provedor de dados: 5
Autores: Girardin, Raphael; Fulton, Elizabeth A.; Lehuta, Sigrid; Rolland, Marie; Thebaud, Olivier; Travers-trolet, Morgane; Vermard, Youen; Marchal, Paul.
The ecosystem model Atlantis was used to investigate the key dynamics and processes that structure the Eastern English Channel ecosystem, with a particular focus on two commercial flatfish species, sole (Solea solea) and plaice (Pleuronectes platessa). This complex model was parameterized with data collected from diverse sources (a literature review, survey data, as well as landings and stock assessment information) and tuned so both simulated biomass and catch fit 2002–2011 observations. Here, the outputs are mainly presented for the two focus species and for some other vertebrates found to be important in the trophic network. The calibration process revealed the importance of coastal areas in the Eastern English Channel and of nutrient inputs from...
Tipo: Text
Palavras-chave: Ecosystem modelling; Flatfish fisheries; Trophic relationships; Calibration; Atlantis; Eastern English Channel.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00354/46524/46289.pdf

Reconciling complex system models and fisheries advice: Practical examples and leads
Provedor de dados: 5
Autores: Lehuta, Sigrid; Girardin, Raphael; Mahevas, Stephanie; Travers-trolet, Morgane; Vermard, Youen.
The move toward an ecosystem-based fisheries management (EBFM) requires new operational tools in order to support management decisions. Among them, ecosystem- and fisheries-based models are critical to quantitatively predict the consequences of future scenarios by integrating available knowledge about the ecosystem across different scales. Despite increasing development of these complex system models in the last decades, their operational use is still currently limited in Europe. Many guidelines are already available to help the development of complex system models for advice yet they are often ignored. We identified three main impediments to the use of complex system models for decision support: (1) their very complexity which is a source of uncertainty;...
Tipo: Text
Palavras-chave: Ecosystem-based fisheries management; Complex models; Decision support; Methodological solutions; Participatory modeling; Model sensitivity analysis; Examples.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00358/46945/46851.pdf

Achieving maximum sustainable yield in mixed fisheries: a management approach for the North Sea demersal fisheries
Provedor de dados: 5
Autores: 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

How do demersal fishing fleets interact with aggregate extraction in a congested sea?
Provedor de dados: 5
Autores: 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

Integrating mark-recapture data within a Bayesian life-cycle model to evaluate spatial structure and population dynamics of sole. A coastal and nursery dependent flatfish : Eastern Channel Sole
Provedor de dados: 5
Autores: Veron, Matthieu; Archambault, Benoit; Rochette, Sebastien; Hunter, Ewan; Lehuta, Sigrid; Randon, Marine; Savina-rolland, Marie; Vermard, Youen; Reveillac, Elodie; Rivot, Etienne; Le Pape, Olivier.
The common sole -Solea solea- is one of the most harvested flatfish population in the Eastern English Channel -EEC; ICES area VIId-. In the EEC, this population is currently assessed and managed as a homogeneous single stock. However, some ecological clues indicate that a metapopulation structure formed by a set of three loosely connected subpopulations associated with local coastal nurseries areas cannot be ruled out. Results show that key estimates of population dynamics parameters, stock assessment and management reference points are highly sensitive to the hypotheses made on the spatial structure. A Bayesian integrated life-cycle model was developed to explore the sensitivity of population dynamics and stock assessment to the level of connectivity in...
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00410/52134/52844.pdf

Evaluation de mesures de gestion pour l’exploitation de la sole en Manche est (sole VIId).
Provedor de dados: 5
Autores: 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
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00228/33960/32299.pdf

Catch-quota balancing in mixed-fisheries: a bio-economic modelling approach applied to the New Zealand hoki (Macruronus novaezelandiae) fishery
Provedor de dados: 5
Autores: 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

Adult-mediated connectivity affects inferences on population dynamics and stock assessment of nursery-dependent fish populations
Provedor de dados: 5
Autores: 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

Evaluation de l’impact de scénarios alternatifs pour l’atteinte du RMD et de mesures de gestion pour les stocks de sole de Manche Est et du golfe de Gascogne et de gadidés de mer Celtique (cabillaud, églefin, merlan).
Provedor de dados: 5
Autores: 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
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00299/41034/79172.pdf

The Best Way to Reduce Discards Is by Not Catching Them!
Provedor de dados: 5
Autores: Reid, David G; Calderwood, Julia; Afonso, Pedro; Bourdaud, Pierre; Fauconnet, Laurence; Gonzalez-irusta, José Manuel; Mortensen, Lars O; Ordines, Francesc; Lehuta, Sigrid; Pawlowski, Lionel; Plet-hansen, Kristian S; Radford, Zachary; Robert, Marianne; Rochet, Marie-joelle; Rueda, Lucia; Ulrich, Clara; Vermard, Youen.
Under the Landing Obligation (LO) fishers will need to reduce or land fish that were previously discarded. In this chapter we look at how they might be able to do that by summarising a number of studies conducted in various European regions. We start by describing a series of “challenge” trials where fishers tried to reduce their discards by whatever (legal) means they thought best. In some cases, they were able to reduce unwanted catches, in others they were less successful. We also interviewed fishers not involved in the trials to ask them what they thought they could do. We explore their approaches which generally fell into three categories: more selective gear; tactical and strategic changes; and management changes. Scientific data (surveys, landings,...
Tipo: Text
Palavras-chave: Challenge trials; Decision support tools; Discard avoidance; Fine scale mapping; Fish distribution; Fishers; Fishing strategies; Hot-spot maps.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00473/58428/61004.pdf

Evaluation de mesures de gestion pour le stock de sole en Manche est.
Provedor de dados: 5
Autores: Vermard, Youen; Savina-rolland, Marie; Biseau, Alain.
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00299/41030/40155.pdf

State-space modeling of multi-decadal mark-recapture data reveals low adult dispersal in a nursery-dependent fish metapopulation
Provedor de dados: 5
Autores: Lecomte, Jean-baptiste; Le Pape, Olivier; Baillif, Hélène; Nevoux, Marie; Vermard, Youen; Savina-rolland, Marie; Veron, Matthieu; Lehuta, Sigrid; Hunter, Ewan; Rivot, Etienne.
Quantifying connectivity within fish metapopulations is an important component in understanding population dynamics and providing an evidence base for assessment and management. We investigate meta-population connectivity of the common sole (Solea solea L.) in the Eastern English Channel (EEC). The EEC common sole stock is currently assessed as a single and spatially homogeneous population but connectivity induced through adult movements within this stock and with nearby stocks remains unknown. To fill this knowledge gap, we developed a state-space mark-recovery model, designed to estimate adult connectivity, using mark-recapture data from multiple release experiments from 1970 to 2018 across the EEC and adjacent management areas. The model estimates...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00515/62634/67003.pdf

An investigation of human vs. technology-induced variation in catchability for a selection of European fishing fleets
Provedor de dados: 5
Autores: 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

The need for a protean fisheries science to address the degradation of exploited aquatic ecosystems
Provedor de dados: 5
Autores: Drouineau, Hilaire; Lobry, Jeremy; Bez, Nicolas; Travers-trolet, Morgane; Vermard, Youen; Gascuel, Didier.
In this introductory paper we highlight key questions that were discussed during the symposium on “Status, functioning and shifts in marine ecosystems” organized by the Association Française d’Halieutique (French Association for Fisheries Sciences, Montpellier, France, July 2015). This symposium illustrated that fisheries science is now working at multiple scales and on all dimensions of socio-ecosystems (ecological, political, sociological, and economic), with a great diversity of approaches and taking into account different levels of complexity while acknowledging diverse sources of uncertainty. We argue that we should go one step further and call for a protean fisheries science to address the deteriorated states of aquatic ecosystems caused by...
Tipo: Text
Palavras-chave: EAFM; Fisheries management; Fisheries science; Marine resources; Models; Uncertainty.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00359/46990/46921.pdf

Evaluating deepwater fisheries management strategies using a mixed-fisheries and spatially explicit modelling framework
Provedor de dados: 5
Autores: 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

The Risky Decrease of Fishing Reference Points Under Climate Change
Provedor de dados: 5
Autores: Travers-trolet, Morgane; Bourdaud, Pierre; Genu, Mathieu; Velez, Laure; Vermard, Youen.
In Europe, implementation of sustainable fisheries management has been reinforced in the latest common fisheries policy, and presently marine fish stocks are mostly managed through assessment of their exploitation and ecological status compared to reference points such as Maximum Sustainable Yield (MSY). However, MSY and its associated fishing mortality rate FMSY are sensitive to both stock characteristics and environment conditions. In parallel, climate change impacts are increasingly affecting fish stocks directly and indirectly but might also change the exploitation reference points and the associated level of catch. Here we explored the variability of MSY reference points under climate change by using a multi-species model applied to the Eastern...
Tipo: Text
Palavras-chave: Maximum sustainable yield; Climate change; Biological reference points; Ecosystem model; Fishery management.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00657/76939/78140.pdf

Mechanisms of change in human behaviour
Provedor de dados: 5
Autores: Marchal, Paul; Bartelings, Heleen; Bastardie, François; Batsleer, Jurgen; Delaney, Alyne; Girardin, Raphael; Gloaguen, Pierre; Hamon, Katell; Hoefnagel, Ellen; Jouanneau, Charlène; Mahevas, Stephanie; Nielsen, Rasmus; Piwowarczyk, Joanna; Poos, Jan-jaap; Schulze, Torsten; Rivot, Etienne; Simons, Sarah; Tidd, Alex; Vermard, Youen; Woillez, Mathieu.
The scope of this report is to present the science developed within the VECTORS project to improve the understanding of the key processes driving the behaviour of human agents utilising a variety of EU maritime domains. While particular attention has been paid to the spatial interactions between fishing activities and other human uses (e.g., maritime traffic, offshore wind parks, aggregate extractions), the behaviour of non-fishing sectors of activity has also been considered. Various quantitative and semi-qualitative approaches have been pursued to gain better insight into behavioural drivers based on past data, and also forecast how human agents would react if access was constrained by either management (e.g. Marine Protected Areas – MPA), or the...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00223/33377/31802.pdf

A model-based evaluation of Marine Protected Areas: the example of eastern Baltic cod (Gadus morhua callarias L.)
Provedor de dados: 5
Autores: 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

Situation en 2011 des ressources exploitées par les flottilles françaises
Provedor de dados: 5
Autores: Biseau, Alain; Bellail, Robert; Bertignac, Michel; Biais, Gerard; Bigot, Jean-louis; Bouche, Ludovic; Bourjea, Jerome; Caro, Anthony; De Casamajor, Marie-noelle; Caill-milly, Nathalie; Drogou, Mickael; Duhamel, Erwan; Fifas, Spyros; Foucher, Eric; Fromentin, Jean-marc; Jadaud, Angelique; Lampert, Luis; Laurans, Martial; Lissardy, Muriel; Lorance, Pascal; Mahe, Jean-claude; Mahe, Kelig; Masse, Jacques; Morandeau, Gilles; Pawlowski, Lionel; Poisson, Francois; Reynal, Lionel; Roos, David; Verin, Yves; Vermard, Youen; Vigneau, Joel.
Ce document présente l'état des principaux stocks exploités par les flottes françaises en termes de mortalité par pêche et de biomasse de reproducteurs. La situation fin 2010 (début 2011) par rapport aux points de référence (de précaution et Fmsy) est indiqué lorsque les indicateurs sont estimés et que les références sont définies. Les grandes tendances en matière d'évolution des mortalités et biomasses sont également indiquées.
Tipo: Text
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00035/14656/11956.pdf

Inferring the annual, seasonal, and spatial distributions of marine species from complementary research and commercial vessels’ catch rates
Provedor de dados: 5
Autores: Bourdaud, Pierre; Travers-trolet, Morgane; Vermard, Youen; Cormon, Xochitl; Marchal, Paul.
The objective of this study is to analyse at fine scale the annual, seasonal and spatial distributions of several species in the Eastern English Channel (EEC). On the one hand, data obtained from scientific surveys are not available all year through, but are considered to provide consistent yearly and spatially resolved abundance indices. On the other hand, on-board commercial data do cover the whole year, but generally provide a biased perception of stock abundance. The combination of scientific and commercial catches per unit of effort (CPUEs), standardized using a delta-generalized linear model, allowed to infer spatial and monthly dynamics of fish distributions in the EEC, which could be compared with previous knowledge on their life cycles....
Tipo: Text
Palavras-chave: Commercial data; Eastern English Channel; Seasonality; Spatial distribution; Survey data.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00387/49805/50385.pdf

Modelling Fishing Vessels Movement and Activity
Provedor de dados: 5
Autores: Gloaguen, Pierre; Mahevas, Stephanie; Rivot, Etienne; Woillez, Mathieu; Guitton, Jérome; Vermard, Youen; Etienne, Marie-pierre.
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00371/48181/48296.pdf

Comportement de pêche et gestion : l’exemple de la pêcherie pélagique du Golfe de Gascogne
Provedor de dados: 5
Autores: 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

Description de l’activité des navires capturant le rouget barbet. Evolution des captures et des débarquements sur la période 2000-2011
Provedor de dados: 5
Autores: 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

Exploring habitat credits to manage the benthic impact in a mixed fishery
Provedor de dados: 5
Autores: 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

Combining multiple data sets to unravel the spatiotemporal dynamics of a data-limited fish stock
Provedor de dados: 5
Autores: 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
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00460/57187/59150.pdf

Reconciling single-species TACs in the North Sea demersal fisheries using the Fcube mixed-fisheries advice framework
Provedor de dados: 5
Autores: Ulrich, Clara; Reeves, Stuart A.; Vermard, Youen; Holmes, Steven J.; Vanhee, Willy.
Single-species management is a cause of discarding in mixed fisheries, because individual management objectives may not be consistent with each other and the species are caught simultaneously in relatively unselective fishing operations. As such, the total allowable catch (TAC) of one species may be exhausted before the TAC of another, leading to catches of valuable fish that cannot be landed legally. This important issue is, however, usually not quantified and not accounted for in traditional management advice. A simple approach using traditional catch and effort information was developed, estimating catch potentials for distinct fleets (groups of vessels) and metiers (type of activity), and hence quantifying the risks of over-and underquota utilization...
Tipo: Text
Palavras-chave: Advice; Demersal; Effort; Fcube; Mixed fisheries; North Sea; TACs.
Ano: 2011
URL: https://archimer.ifremer.fr/doc/00044/15491/12970.pdf

Thirty years of fleet dynamics modelling using discrete-choice models: What have we learned?
Provedor de dados: 5
Autores: Girardin, Raphael; Hamon, Katell; Pinnegar, John; Poos, Jan Jaap; Thebaud, Olivier; Tidd, Alex; Vermard, Youen; Marchal, Paul.
Anticipating fisher behaviour is necessary for successful fisheries management. Of the different concepts that have been developed to understand individual fisher behaviour, random utility models (RUMs) have attracted considerable attention in the past three decades, and more particularly so since the 2000s. This study aimed at summarizing and analysing the information gathered from RUMs used during the last three decades around the globe. A methodology has been developed to standardize information across different studies and compare RUM results. The studies selected focused on fishing effort allocation. Six types of fisher behaviour drivers were considered: the presence of other vessels in the same fishing area, tradition, expected revenue, species...
Tipo: Text
Palavras-chave: Fisher behaviour; Meta-analysis; Random utility model.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00357/46834/47127.pdf

Réponse à la saisine DPMA 13-5771 évaluation des conséquences socio-économiques de réduction de TAC.
Provedor de dados: 5
Autores: Biseau, Alain; Macher, Claire; Daures, Fabienne; Merzereaud, Mathieu; Biais, Gerard; Vermard, Youen.
Tipo: Text
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00280/39150/37714.pdf

Hotspot mapping in the Celtic Sea: An interactive tool using multinational data to optimise fishing practices
Provedor de dados: 5
Autores: Calderwood, Julia; Robert, Marianne; Pawlowski, Lionel; Vermard, Youen; Radford, Zachary; Catchpole, Thomas L.; Reid, David G.
As a result of the introduction of the Landing Obligation in European fisheries there is a need to equip industry with the tools and knowledge to avoid unwanted catches. Optimising fishing practices in terms of time and location fished have been acknowledged as being important in modulating catch composition. Mapping techniques used to identify and manage the spatio-temporal nature of bycatch, however, remain underutilized. Data collected on board commercial fishing vessels by observers provides an important source of information on the component of catches discarded. Using a unique dataset, combining observer data for Irish, French and British vessels operating in the Celtic Sea between 2010 and 2015, maps were developed to identify where catches of quota...
Tipo: Text
Palavras-chave: Landing obligation; Discards; Consistent maps; Fishing tactics; Shiny app; Celtic sea.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00590/70162/68235.pdf

Combining fleet dynamics and population dynamics for a volatile fishery: the example of the anchovy fishery of the Bay of Biscay
Provedor de dados: 5
Autores: 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
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00107/21858/19449.pdf