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| Registros recuperados: 47 | |
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| Doray, Mathieu; Petitgas, Pierre; Nelson, Laetitia; Mahevas, Stephanie; Josse, E; Reynal, Lionel. |
| Fish-aggregating devices (FADs) are increasingly used worldwide to enhance tuna catches. Meanwhile, ecosystem-based management of this fishery is constrained by a paucity of information regarding the interaction of FAD-associated tuna aggregations with their local environment. This paper reports the results of a nine-month study around a FAD moored near Martinique Island, aimed at assessing the effects of the local environment on the variability of monthly estimates of proximate tuna biomass. Dual-frequency, active acoustics provided highresolution quantitative data on the pelagic community around the FAD, from fish to micronekton forage. Geostatistics were used to compute biomass estimates of the tuna aggregation comprising most of the FADassociated fish... |
| Tipo: Text |
Palavras-chave: Lesser Antilles; Tuna; Environment; Geostatistics; Biomass estimation; Fish aggregating device. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6162.pdf |
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| 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 |
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| Deporte, Nicolas; Ulrich, Clara; Mahevas, Stephanie; Demaneche, Sebastien; Bastardie, Francois. |
| The European Common Fisheries Policy recognizes the importance of accounting for heterogeneity in fishing practices, and metier-based sampling is now at the core of the EU Data Collection Framework. The implementation of such an approach would require Member States to agree on the standard regional metier definitions and on practical rules to categorize logbook records into metiers. Several alternative approaches have been used in the past to categorize landings profiles, but no consensus has yet emerged. A generic open-source workflow is developed to test and compare a selection of methods, including principal components analysis (PCA), hierarchical agglomerative clustering (HAC), K-means, and Clustering LARge Applications (CLARA), and to provide simple... |
| Tipo: Text |
Palavras-chave: Cluster; Data Collection Framework (DCF); Logbooks; Mtier; Mixed fisheries; Multivariate analysis; North Sea. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00071/18225/15841.pdf |
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| Biseau, Alain; Mahevas, Stephanie; Perodou, Jean-bernard; Berthou, Patrick. |
| Three fleets of the French fishery are investigated : the dredge fleet of the Western part of the Channel, the bottom-trawl fishery of South-Britanny harbours, and the Mediterranean trawl fishery. Landing and effort data by species, vessel and trip lead to yields (catch per unit of effort) which are analysed by a multicplicative model with two or three factors. Individual fishing powers are then quantified for some given years, together with variation in relative abundance of the stock within area and/or period strata. Attempts to explain these fishing powers by vessels characteristics are made. After the study of the Mediterranean trawl-fleet, which takes Year into account in the model, two multi-annual series are analysed, and some conclusions on fishing... |
| Tipo: Text |
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| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00327/43785/43343.pdf |
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| Marchal, Paul; Andersen, B; Bromley, D; Iriondo, A; Mahevas, Stephanie; Quirijns, F; Rackham, B; Santurtun, M; Tien, N; Ulrich, Clara. |
| The scope of this paper is to quantify, for a wide selection of European fisheries, fishing tactics and strategies and to evaluate the benefits of adjusting the definition of. fishing effort using these elements. Fishing tactics and strategies were identified by metiers choices and a series of indices. These indices have been derived to reflect shifts in tactics (within a fishing trip) and in strategies (within a year). The Shannon-Wiener spatial diversity indices of fishing tactics (FT_SW) and strategies (YE_SW) had the greatest impact on catch rates. In particular, FT_SW was always negatively correlated to catch rates. One may anticipate that during a fishing trip, vessels with high FT_SW have been searching fish aggregations for a long time, while... |
| Tipo: Text |
Palavras-chave: Fishing effort; Fishing mortality; Catch rates; GLM modeling; Skipper effect. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/2006/publication-1339.pdf |
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| 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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| Drouineau, Hilaire; Mahevas, Stephanie; Pelletier, Dominique; Beliaeff, Benoit. |
| In this paper, we present an approach to compare the impact of different management options oil the dynamics of a mixed fishery. We used ISIS-Fish, a simulation tool aimed at evaluating the impact of spatial and seasonal management measures on the dynamics of mixed fisheries. The French Nephrops norvegicus (Norway lobster) Merluccius merluccius (hake) mixed fishery of the Bay of Biscay was chosen as a Study case. First, we parameterised the Population and exploitation models. We then selected several management measures, including marine protected fishermen's reaction to each measure. Then, a sensitivity analysis (MPAs) and total allowable catches (TAC), and parameterised fish sensitivity analysis was performed according to a fractional factorial... |
| Tipo: Text |
Palavras-chave: Simulation design; Sensitivity analysis; Management measures; Spatial model; Fisheries dynamics. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1340.pdf |
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| Peck, Myron A.; Arvanitidis, Christos; Butenschon, Momme; Canu, Donata Melaku; Chatzinikolaou, Eva; Cucco, Andrea; Domenici, Paolo; Fernandes, Jose A.; Gasche, Loic; Huebert, Klaus B.; Hufnagl, Marc; Jones, Miranda C.; Kempf, Alexander; Keyl, Friedemann; Maar, Marie; Mahevas, Stephanie; Marchal, Paul; Nicolas, Delphine; Pinnegar, John K.; Rivot, Etienne; Rochette, Sebastien; Sell, Anne F.; Sinerchia, Matteo; Solidoro, Cosimo; Somerfield, Paul J.; Teal, Lorna R.; Travers-trolet, Morgane; Van De Wolfshaar, Karen E.. |
| We review and compare four broad categories of spatially-explicit modelling approaches currently used to understand and project changes in the distribution and productivity of living marine resources including: 1) statistical species distribution models, 2) physiology-based, biophysical models of single life stages or the whole life cycle of species, 3) food web models, and 4) end-to-end models. Single pressures are rare and, in the future, models must be able to examine multiple factors affecting living marine resources such as interactions between: i) climate-driven changes in temperature regimes and acidification, ii) reductions in water quality due to eutrophication, iii) the introduction of alien invasive species, and/or iv) (over-)exploitation by... |
| Tipo: Text |
Palavras-chave: Distribution; Modelling; Habitat; Resources; Man-induced effects. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00337/44845/44436.pdf |
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| Lopez, Romain; De Pontual, Helene; Bertignac, Michel; Mahevas, Stephanie. |
| European sea bass, Dicentrarchus labrax, is a highly valuable species in Europe, both for aquaculture in the Mediterranean Sea and for commercial and recreational fisheries in the North East Atlantic Ocean. Subjected to increasing fishing pressure, the wild population has recently experienced significant recruitment fluctuation as well as a northward extension of its distribution area in the North Sea. While the nature of the ecological and/or physiological processes involved remains unresolved, ontogenetic habitat shifts and adult site fidelity could increase the species’ vulnerability to climate change and overfishing. As managers look for expert information to propose management scenarios leading to sustainable exploitation, exploratory modelling... |
| Tipo: Text |
Palavras-chave: Population dynamics; Essential habitats; Connectivity; Bioenergetic modeling; Phenotypic plasticity; Life cycle adaptation. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00341/45258/44699.pdf |
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| Drouineau, Hilaire; Mahevas, Stephanie; Bertignac, Michel; Duplisea, Daniel. |
| Drouineau, H., Mahevas, S., Bertignac, M., and Duplisea, D. 2010. A length-structured spatially explicit model for estimating hake growth and migration rates. - ICES Journal of Marine Science, 67: 1697-1709. |
| Tipo: Text |
Palavras-chave: Growth; Length-structured model; Merluccius merluccius; Migration; Spatial model. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00016/12714/9767.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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| Tissiere, Laurie; Michel, Charlotte; Mahevas, Stephanie; Trouillet, Brice. |
| Prospective studies considered that the future is not determined. Time is then a lever to enhance debates. More recently, << geoprospective >> has integrated space in discussions about possible futures. That questions directly the functions of the spatial and the temporal dimensions, especially the capacity of space and time to play as intermediaries for participation. We applied this question on the case of a fishery in the Bay of Biscay. On the one hand, we demonstrated that the participative method, combining qualitative and quantitative approaches, as well as simple and complex tools, allowed to describe the stakes of the case study and to imagine spatially-explicit possible changes. On the other hand, we also pointed that space and time... |
| Tipo: Text |
Palavras-chave: Géoprospective; Participations; Méthodes spatio-temporelles; Représentations; Pêches maritimes; Geoprospective; Participations; Spatial and temporal methods; Representations; Fisheries. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00449/56039/57557.pdf |
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| Gasche, Loic; Mahevas, Stephanie; Marchal, Paul. |
| Ecosystems are usually complex, nonlinear and strongly influenced by poorly known environmental variables. Among these systems, marine ecosystems have high uncertainties: marine populations in general are known to exhibit large levels of natural variability and the intensity of fishing efforts can change rapidly. These uncertainties are a source of risks that threaten the sustainability of both fish populations and fishing fleets targeting them. Appropriate management measures have to be found in order to reduce these risks and decrease sensitivity to uncertainties. Methods have been developed within decision theory that aim at allowing decision making under severe uncertainty. One of these methods is the information-gap decision theory. The info-gap... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00166/27746/25947.pdf |
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| Doray, Mathieu; Mahevas, Stephanie; Trenkel, Verena. |
| Few analyses have been performed to estimate the efficiency of trawls targeting demersal fish using the ratio of catches and acoustic densities. In summer 2006, acoustic and fishing data were collected simultaneously over 3 d by three fishing vessels equipped with identical pelagic trawls in the Bay of Biscay. Variography identified moderate spatial autocorrelation in the acoustic backscatter at a mean scale of 3 km, a scale slightly smaller than the mean haul length (3.5 km), indicating that fish horizontal availability did not influence trawl efficiency. Acoustic backscattering densities expressed as nautical area scattering coefficients (NASCs) recorded in the trawled layer were compared with equivalent NASC (ENASC) values calculated from the species... |
| Tipo: Text |
Palavras-chave: Availability; Bay of Biscay; Catchability; Generalized linear model; Geostatistics; Hake; Vulnerability. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00002/11372/7980.pdf |
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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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| Drouineau, Hilaire; Lobry, Jeremy; Delpech, C.; Bouchoucha, Marc; Mahevas, Stephanie; Courrat, A.; Pasquaud, S.; Lepage, M.. |
| In the context of the European Water Framework Directive (WFD), monitoring programs and related indicators have been developed to assess anthropogenic impacts on various components of aquatic ecosystems. While great precautions are usually taken when selecting and calculating relevant core metrics, little attention is generally paid to the generation of the multimetric indicator, i.e. the combination of the different core metrics. Indeed, most multimetric indicators are generated by simply averaging or summing metrics, without taking into account their sensitivity and their variability. Moreover, few indicators provide a rigorous estimate of the uncertainty of the assessments, while this estimation is essential for managers. In this context, we developed a... |
| Tipo: Text |
Palavras-chave: Multimetric fish-based indicator; Bayesian method; Pressure-impact models; Water Framework Directive; Anthropogenic pressure; Monitoring program; Transitional waters. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00049/16037/13572.pdf |
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| Registros recuperados: 47 | |
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