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| Registros recuperados: 25 | |
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| Lehuta, Sigrid; Mahevas, Stephanie; Le Floc'H, Pascal; Petitgas, Pierre. |
| Indicators are widely promoted as means to monitor ecosystem status or to evaluate fisheries management performance. "Which indicators are most relevant as decision-support tools in fisheries management?" still remains a topical question. Indicators should be metrics related to fish populations and fleets and should be sensitive to management strategies. However, given the complexity of the processes involved, it is often difficult to unequivocally interpret variations in metrics. A simulation approach was used to study metric properties and to identify robust and relevant fishery indicators. By applying sensitivity analysis methods, simulation designs were built that cross a variety of management scenarios and uncertainty hypotheses. Bio-economic outputs... |
| Tipo: Text |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00170/28093/26627.pdf |
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| Marchal, Paul; Francis, Chris; Lallemand, Philippe; Lehuta, Sigrid; Mahevas, Stephanie; Stokes, Kevin; Vermard, Youen. |
| Managing adequately the exploitation of commercial species subject to technical interactions is a key step towards the ecosystem approach to fisheries. We evaluate here, using a bio-economic modelling approach building on the ISIS-Fish simulation platform, the relative impact of total allowable commercial catches (TACC) and of taxes applicable to over-quota landings (deemed value) on the sustainability of a selection of species exploited by the New Zealand hoki (Macruronus novaezelandiae) fishery. We investigate some aspects of the hoki mixed fisheries, consisting of four fleets and nineteen metiers, by considering the technical interactions between hoki and Southern hake (Merluccius australis). The dynamics of effort allocation were modelled using gravity... |
| Tipo: Text |
Palavras-chave: Fleet dynamics; New Zealand hoki fishery; Deemed value; Fisheries management. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00000/11168/7521.pdf |
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| Blanluet, Arthur; Doray, Mathieu; Berger, Laurent; Romagnan, Jean-baptiste; Le Bouffant, Naig; Lehuta, Sigrid; Petitgas, Pierre. |
| Sound scattering layers (SSLs) are observed over a broad range of spatio-temporal scales and geographical areas. SSLs represent a large biomass, likely involved in the biological carbon pump and the structure of marine trophic webs. Yet, the taxonomic composition remains largely unknown for many SSLs. To investigate the challenges of SSL sampling, we performed a survey in a small study area in the Northern Bay of Biscay (France) by combining broadband and narrowband acoustics, net sampling, imagery and video recordings. In order to identify organisms contributing to the observed SSLs, we compared measured frequency spectra to forward predicted spectra derived from biological data. Furthermore, to assess the confidence in SSL characterization, we evaluated... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00588/70035/67955.pdf |
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| Vermard, Youen; Lehuta, Sigrid; Mahevas, Stephanie; Thebaud, Olivier; Marchal, Paul; Gascuel, Didier. |
| It is increasingly recognized that fisher‟s behavior should be taken into account to understand and predict fishery dynamics, in particular in response to management. ISIS-Fish is a spatially and seasonally explicit modeling framework especially designed to couple populations and fleets dynamics and explore the impact of various management measures on mixed fisheries. It has already been set up using a static fishing effort allocation (corresponding to an average historical pattern) between the various métiers to simulate the pelagic fishery in the Bay of Biscay. We present here the integration of a fleet dynamics model. This model is derived from a Random Utility Model simulating métiers choice using as explanatory variables the past value per unit... |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00107/21858/19449.pdf |
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| Biseau, Alain; Lissardy, Muriel; Marre, Guilhem; Daures, Fabienne; Macher, Claire; Merzereaud, Mathieu; Le Grand, Christelle; Gourguet, Sophie; Berthou, Patrick; Lehuta, Sigrid; Vermard, Youen; Savina-rolland, Marie. |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00299/41034/79172.pdf |
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| Vermard, Youen; Lehuta, Sigrid; Savina-rolland, Marie; Biseau, Alain. |
| La DPMA sollicite l’Ifremer pour déterminer la réduction de la mortalité par pêche nécessaire pour l’atteinte de l’objectif du Rendement Maximum Durable (RMD) entre 2015 et 2020, avec l’estimation des Totaux Admissibles de Capture (TAC) pour chaque année. La DPMA souhaite également faire appel à l’expertise de votre Institut pour évaluer les mesures de gestion proposées ci-après par une estimation de la réduction de la mortalité par pêche, ou par une estimation des impacts potentiels, en cas de données insuffisantes : - Limitation de l’effort de pêche par flottille par une réduction du nombre de jour de pêche. Une répartition par flottille et par mois de la mortalité par pêche est nécessaire pour déterminer s’il existe une saisonnalité sur cette pêcherie,... |
| Tipo: Text |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00228/33960/32299.pdf |
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| Mills, Katherine E.; Pershing, Andrew J.; Brown, Curtis J.; Chen, Yong; Chiang, Fu-sung; Holland, Daniel S.; Lehuta, Sigrid; Nye, Janet A.; Sun, Jenny C.; Thomas, Andrew C.; Wahle, Richard A.. |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00168/27912/26194.pdf |
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| 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 |
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| Lehuta, Sigrid; Huret, Martin; Issac, Pierre; Petitgas, Pierre. |
| CERES a pour objectif de mieux comprendre comment le changement climatique influencera les ressources les plus importantes de poissons et de crustacés d'Europe ainsi que les actvités économiques qui en dépendent. CERES fournira des outils et des stratégies d'adaptation permettant aux secteurs des pêches et de l'aquaculture marines et continentales et à leur gouvernance de se préparer aux changements défavorables, ou aux opportunités futures dans certains cas, du changement climatique. IFREMER s'intéresse dans ce projet au cas d'étude de la pêcherie pélagique du golfe de Gascogne, et en particulier aux espèces anchois et sardine. Les changements attendus sur la pêcherie de petits pélagiques concernent (I) la distributon spatiale aux différents stades de... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00470/58155/60649.pdf |
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| Marandel, Florianne; Lorance, Pascal; Andrello, Marco; Charrier, Gregory; Le Cam, Sabrina; Lehuta, Sigrid; Trenkel, Verena. |
| Studying demographic and genetic connectivity can help assessing marine meta-population structure. Rays and skates have no larval phase hence population connectivity can only result from active movement of individuals. Using thornback ray (Raja clavata) in European waters as a case study, demographic and genetic connectivity were studied for 11 putative populations for unequal population abundances and two hypotheses of dispersal rates. Genetic simulation results highlighted three large meta-populations: in the Mediterranean, around the Azores and on the Northeast Atlantic shelf. Demographic results highlighted a finer population structure indicating that several pairs of putative populations might be demographically linked. Results were highly... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00404/51535/52125.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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| 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 |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00410/52134/52844.pdf |
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| Lehuta, Sigrid; Holland, Daniel S.; Pershing, Andrew J.. |
| Ostensibly separate fisheries are often linked through ecological, environmental, and human mediated processes that can impact their productivity, profitability, and resilience; however, managers rarely explicitly account for these linkages. We present a coupled bioeconomic model of the American lobster (Homarus americanus) and Atlantic herring (Clupea harengus) fisheries in the northeast United States. The model builds upon existing stock assessment models and includes key characteristics of both fisheries including size- or age-structured populations, seasonal patterns of lobster exploitation, and seasonal-spatial patterns of herring exploitation. The lobster and herring models are linked through a bait market module that drives behavior of the herring... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00181/29252/27679.pdf |
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| 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 |
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| Hoff, Ayoe; Frost, Hans; Andersen, Peder; Prellezo, Raul; Rueda, Lucia; Triantaphyllidis, George; Argyrou, Ioanna; Tsikliras, Athanassios; Motova, Arina; Lehuta, Sigrid; Curtis, Hazel; Rodriguez-rodriguez, Gonzalo; Ballesteros, Hugo M; Valeiras, Julio; Bellido, José Maria. |
| To assess the likely economic outcomes to fishing fleets of the Landing Obligation (LO), bioeconomic models covering seven European fisheries, ranging from the North East Atlantic to the Mediterranean, have been applied to estimate the economic performance of fleets before and after implementing the LO. It is shown that for most of the analysed fisheries, their economic outcome will be negatively affected in the long term by the LO, when compared to the expected outcome with no LO. Efficient mitigation strategies (exemptions, quota uplifts, improved selectivity, effort reallocation and others) may, for some of the analysed fisheries, reduce the negative economic effect of the LO. Moreover, the possibility to trade quotas, both nationally and... |
| Tipo: Text |
Palavras-chave: Costs and earnings; Discards; Economic repercussions; Fisheries management; Fleet adjustment. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00473/58435/61010.pdf |
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| Lehuta, Sigrid; Petitgas, Pierre; Mahevas, Stephanie; Huret, Martin; Vermard, Youen; Uriarte, Andres; Record, Nicholas R.. |
| Assessing the validity of a model is essential for its credibility especially when the model is used as decision making tool. Complex dynamic fishery models are recommended to investigate the functioning of fisheries and to assess the impact of management strategies, particularly spatial fishing regulations. However, their use is limited due to the difficulty and computational cost of parameterizing and gaining confidence, particularly for parameter rich models. These difficulties are compounded by uncertainty regarding parameter values, many of which are often taken from literature or estimated indirectly. Here we propose a methodology to improve confidence and understanding in the model, easily transferable to any complex model. The approach combines... |
| Tipo: Text |
Palavras-chave: Bay of Biscay anchovy; Dynamic fishery model; Model selection; Uncertainty; Validation. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00148/25965/24150.pdf |
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| Registros recuperados: 25 | |
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