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Registros recuperados: 26 | |
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Raveau, Adriana; Macher, Claire; Mehault, Sonia; Merzereaud, Mathieu; Le Grand, Christelle; Guyader, Olivier; Bertignac, Michel; Fifas, Spyros; Guillen Garcia, Jordi. |
Several fleets with various fishing strategies operate as a mixed fishery in the Bay of Biscay. Among the main fleets, bottom trawlers target Norway lobster (Nephrops norvegicus) and, together with gillnetters, they also catch hake (Merluccius merluccius). Trawling leads to average-size catches that are below the minimum landing size (MLS); such catches are discarded since they cannot be sold. These discards result in negative impacts on stock renewal, as most of them do not survive. This also results in an economic loss for both bottom trawlers and gillnetters since these discards represent a future loss of rent. This study, based on the 2009 and 2010 selectivity experiments at sea, assesses the short- and long-term bio-economic impacts of four... |
Tipo: Text |
Palavras-chave: Demersal trawl fishery; Bio-economic analysis; Selectivity; Simulation; Selective device; Nephrops norvegicus; Merluccius merluccius; Atlantic Ocean. |
Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00110/22135/19774.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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Le Floc'H, Pascal; Bertignac, Michel; Curtil, Olivier; Macher, Claire; Mariat-roy, Emilie; Paulet, Yves-marie. |
This study considers how to reconcile different spatial scales to find the best common denominator to be used as an ecosystem-based management unit. For this, two fishery production zones differing ecologically, economically, legally and institutionally were investigated. The first case study is located within French territorial waters, in a MPA created in 2007- the Parc Naturel Marin d'Iroise (PNMI). The second case study, the Bay of Biscay, covers both territorial waters and the French exclusive economic zone. The paper adopts a multidisciplinary approach. Relevant questions concern how marine space is shared between exploited species and fishing fleets, especially the spatial mobility strategies they employ. An assessment of the institutional system... |
Tipo: Text |
Palavras-chave: Spatial scale; Ecosystem-based fisheries management; Marine protected area; Socio-system. |
Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00460/57191/59156.pdf |
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Doyen, Luc; Thebaud, Olivier; Bene, Christopher; Martinet, V.; Gourguet, S.; Bertignac, Michel; Fifas, Spyros; Blanchard, Fabian. |
Academia and management agencies show a growing interest for ecosystem-based fishery management (EBFM). However, the way to operationalize this approach remains challenging. The present paper illustrates how the concepts of stochastic co-viability, which accounts for dynamic complexities, uncertainties, risk and sustainability constraints, can be useful for the implementation of EBFM. In the present case, this concept is used to identify fishing strategies that satisfy both ecological conservation and economic sustainability in a multi-species, multi-fleet context. Economic Viability Analysis (EVA) and the broader Co-Viability Analysis (CVA), are proposed to expand the usual Population Viability Analysis (PVA) and precautionary approach. An illustration is... |
Tipo: Text |
Palavras-chave: Ecosystem based fisheries management; Viability; Stochastic; Nephrops; Hake. |
Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00074/18571/16153.pdf |
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Ortiz De Zarate, Victoria; Bertignac, Michel. |
In this study, an attempt is made to estimate natural mortality rate for North Atlantic albacore. We implement a spatially aggregated tag-attrition model to analyse the results of an albacore tagging experiment conducted in the Bay of Biscay from 1988 to 1991. The model predicts probabilities of the possible fates of tagged fish and the tags that they carry. The model includes several parameters consisting of catchabilities by fleets involved in recaptures and a combination of natural mortality plus emigration from the study area. Model fitting is carried out by finding the maximum of a multinomial likelihood function. Effect of reporting rate values on the estimations are evaluated and several hypothesis on the pre-mixing period of the tagged fish... |
Tipo: Text |
Palavras-chave: Bay of Biscay; Attrition rate; Model; Natural mortality estimation; Albacore. |
Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-977.pdf |
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Drouineau, Hilaire; Mahevas, Stephanie; Bertignac, Michel; Fertin, A. |
Most of the traditional assessment models are age-structured. However, many biological and exploitation processes are more length-dependent than age-dependent, and the required length-age conversion of available data is often not reliable. Consequently, length-structured or age-length structured models have undergone considerable development in recent years. The growth transition matrix used to model the mean growth and growth variability of the population, is of primary importance in a length-structured matrix model. Building this growth transition matrix is not trivial and it is necessary to assess the impact that various assumptions may have to identify robust model structures. In this study, we assess the effects of (1) time and length discretisation,... |
Tipo: Text |
Palavras-chave: Sensitivity analysis; Discrete model; Growth; Length structured model. |
Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4301.pdf |
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Bertignac, Michel; De Pontual, Helene. |
The results of a pilot tagging study on hake (Merluccius merluccius), conducted in the northern part of the Bay of Biscay in 2002, indicate that growth rates for this stock may be currently underestimated because of biased estimates of age. The impact that such a bias may have on the stock dynamics and the trends of the key population parameters, recruitment, spawning-stock biomass (SSB), and mortality are investigated. Assuming new growth parameters, a new age-length key is derived and used to produce and catch-at-age data and abundance indices, which are then used to assess the stock. Bias in estimating age affects the absolute levels of fishing mortality and stock biomass estimates, and also impacts the trend in SSB. However, trends in fishing mortality... |
Tipo: Text |
Palavras-chave: Tagging; Stock assessment; Simulation; Management; Growth; European hake; Age estimation. |
Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2824.pdf |
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Véron, Matthieu; Duhamel, Erwan; Bertignac, Michel; Pawlowski, Lionel; Huret, Martin; Baulier, Loic. |
Age and size at maturation appear as key parameters governing the dynamics of a population as they affect growth rate, fecundity, and survival. The expression of such life history traits is determined by genetic make-up and modulated by environmental factors mainly through phenotypic plasticity. Moreover, fishing, besides decreasing population size and changing demographic composition can alter allelic frequencies through fisheries-induced evolution by selecting for some particular traits. In the Bay of Biscay, a decreasing trend in both sardine body condition and size-at-age has recently been pointed out at the population level. The Probabilistic Maturation Reaction Norm (PMRN) approach was applied to help disentangle phenotypic plasticity and genetic... |
Tipo: Text |
Palavras-chave: Fisheries-induced evolution; Body condition; Phenotypic plasticity; Maturation; Growth; Sardina pilchardus; Bay of biscay. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00660/77203/78637.pdf |
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Doyen, Luc; Bene, Christophe; Bertignac, Michel; Blanchard, Fabian; Cisse, Abdoul; Dichmont, Catherine; Gourguet, Sophie; Guyader, Olivier; Hardy, Pierre-yves; Jennings, Sarah; Little, Lorne Richard; Macher, Claire; Mills, David Jonathan; Noussair, Ahmed; Pascoe, Sean; Pereau, Jean-christophe; Sanz, Nicolas; Schwarz, Anne-maree; Smith, Tony; Thebaud, Olivier. |
Reconciling food security, economic development and biodiversity conservation is a key challenge, especially in the face of the demographic transition characterizing many countries in the world. Fisheries and marine ecosystems constitute a difficult application of this bio-economic challenge. Many experts and scientists advocate an ecosystem approach to manage marine socio-ecosystems for their sustainability and resilience. However, the ways by which to operationalize ecosystem-based fisheries management (EBFM) remain poorly specified. We propose a specific methodological framework-viability modelling-to do so. We show how viability modelling can be applied using four contrasted case-studies: two small-scale fisheries in South America and Pacific and two... |
Tipo: Text |
Palavras-chave: Biodiversity; Ecological economics; Ecosystem approach; Fisheries; Scenario; Viability. |
Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00409/52009/52724.pdf |
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Guillen, Jordi; Macher, Claire; Merzereaud, Mathieu; Bertignac, Michel; Fifas, Spyros; Guyader, Olivier. |
Most worldwide fish stocks are overexploited, and so exploited beyond the Maximum Sustainable Yield (MSY) and the Maximum Economic Yield (MEY). Not exploiting fisheries resources at MSY or MEY leads to the loss of production and rents from the fisheries. A large part of the EU fisheries are managed based on single species stock assessments; however, in reality, most species are caught together with other species and by different fleets. In multi-species and multi-fleet fisheries, single species assessments, and consequently MSY and MEY reference points, are often not valid, and so the catch recommendations. In this paper it is investigated the MSY and MEY estimation in multi-species and multi-fleet fisheries in comparison to single species assessments.... |
Tipo: Text |
Palavras-chave: MSY; MEY; Multi-species; Multi-fleet; Fisheries; Bio-economic model. |
Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00129/24000/22053.pdf |
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Bertignac, Michel; Moguedet, Philippe. |
An adaptation to the cohort analysis is suggested when age catches distribution are known only on a year and when the effort datas ot previouses years, for each ot the vessels fishing the considerated stock, are availables. An example to the estimation of fish mortality coefficients and of the recruitment abundancy for the stocks of sea bass (Dicentrarchus labrax) from Morbras (ICES division VIII A) and ling (Molva molva) from west of Scotland (ICES division VI A), is given. |
Tipo: Text |
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Ano: 1987 |
URL: http://archimer.ifremer.fr/doc/00396/50756/51465.pdf |
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Bertignac, Michel; Auby, Isabelle; Sauriau, Pierre-guy; De Montaudouin, Xavier; Foucard, Julie; Martin, Sophie. |
As part of a larger project financed by the European Union programme "Community initiative PESCA" on the study of "small scale fisheries" in Aquitaine (France), an estimation of the stock of clams in the Bassin d'Arcachon has been conducted. A two-stage stratified random sampling survey has been designed. Samples have been collected using a Hamon bottom sampler in 237 locations distributed over 24 km2. The clam Tapes philippinarum, which appeared in the basin following a series of aquaculture experiments in the mid eighties, is now the main species accounting for more than 90% of the abundance and the biomass, largely overcoming the European species Tapes decussata. The mean abundance and biomass (26 clams / m2 et l28g / m2) are above those estimated in... |
Tipo: Text |
Palavras-chave: Palourde; Tapes philippinarum; Tapes decussata; Evaluation stock; Pêche; Pêche à pied; Echantillonnage; Bassin d'Arcachon; Clam; Tapes philippinarum; Tapes decussata; Stock assessment; Fishery; Sampling; Bassin d'Arcachon. |
Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00105/21658/19240.pdf |
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Veron, Matthieu; Lebigre, Christophe; Bertignac, Michel; Doray, Mathieu; Duhamel, Erwan; Huret, Martin; Pawlowski, Lionel. |
Peu de modèles d'évaluation de stock intègrent une description fine des processus biologiques régissant les populations exploitées par la pêche au sein des écosystèmes. Ce manque est particulièrement regrettable dans le cas des petits pélagiques dont la dynamique est fortement influencée par les conditions environnementales. En effet, la pêche et les fluctuations environnementales et climatiques impactent fortement la dynamique de population de la sardine du golfe de Gascogne. Pour comprendre la dynamique de cette population au sein de l'écosystème et les effets des pêcheries, il est donc nécessaire d'identifier et de caractériser cet ensemble de pressions. Afin d'améliorer la gestion et le suivi de la dynamique de ce stock, le développement d'un modèle... |
Tipo: Text |
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Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00410/52133/52842.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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Registros recuperados: 26 | |
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