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| Registros recuperados: 24 | |
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| Alemany, Juliette; Rivot, Etienne; Foucher, Eric; Vigneau, Joel; Robin, Jean-paul. |
| Among the English Channel fishery, the importance of cuttlefish stock has increased, following the cephalopods global landings and market trend. An adapted stock assessment model is needed in order to give good management advice with accurate uncertainties. Age based methods in this species are hampered by time consuming age determination with statoliths. A model requiring few data and adapted to the species life-history is therefore proposed. An assessment of this stock was conducted in June 2015 by fitting a two-stage biomass model on a 22 years’ time-series (1992-2014). The use of a Bayesian framework is particularly adapted for decision making, allowing the propagation of uncertainty in the model. It also permits the use of different sources of... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00379/49066/49514.pdf |
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| Gascuel, D.; Bez, Nicolas; Forest, Andre; Guillotreau, P.; Laloe, F.; Lobry, Jeremy; Mahevas, Stephanie; Mesnil, Benoit; Rivot, Etienne; Rochette, S.; Trenkel, Verena. |
| We, members of the Association Francaise d'Halieumetrie, share the conviction that European fisheries have a future. It is time to get off the wrong track. Radical change is required to embark on the path of sustainable development and truly implement the ecosystem approach to fisheries. Today, high fishing pressure is deployed to catch a rare resource, which in return is responsible for the rarity. We must reverse the situation: an abundant resource that affords high catches applying moderate fishing pressure. All management tools and especially all actors must be mobilized. The transition is not simple, and European solidarity must accompany the changes. It is well worth the effort. By reducing fishing pressure, it will be possible in the medium term to... |
| Tipo: Text |
Palavras-chave: Access regulation; Ecosystem approach to fisheries; European Common Fishery Policy; ITQ; MPA; MSY; Management plan; Overcapacity; Subsidies. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00035/14598/11947.pdf |
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| Archarnbault, Benoit; Le Pape, Olivier; Baulier, Loic; Vermard, Youen; Veron, Matthieu; Rivot, Etienne. |
| We explore how alternative hypotheses on the degree of mixing among local subpopulations affect statistical inferences on the dynamics and stock assessment of a harvested flatfish population, namely, the common sole population in the Eastern Channel (ICES area VIId). The current paradigm considers a single, well-mixed, spatially homogeneous population with juveniles from all coastal nursery grounds along the French and UK coasts that contribute to a single adult population and one pool of eggs. Based on the available data and ecological knowledge, we developed a spatial Bayesian integrated life-cycle model that consists of three subpopulations (one near the UK coast and two near the French coast, denoted UK, West FR and East FR, respectively) supported by... |
| Tipo: Text |
Palavras-chave: Solea solea; Spatial life-cycle model; Coastal nurseries; Connectivity; Stock assessment; Hierarchical bayesian model. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00333/44430/44231.pdf |
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| 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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| Dortel, Emmanuelle; Sardenne, Fany; Bousquet, N.; Rivot, Etienne; Million, Julien; Le Croizier, Gael; Chassot, Emmanuel. |
| The Indian Ocean Tuna Tagging Program provided a unique opportunity to collect demographic data on the key commercially targeted tropical tuna species in the Indian Ocean. In this paper, we focused on estimating growth rates for one of these species, yellowfin (Thunnus albacares). Whilst most growth studies only draw on one data source, in this study we use a range of data sources: individual growth rates derived from yellowfin that were tagged and recaptured, direct age estimates obtained through otolith readings, and length-frequency data collected from the purse seine fishery between 2000 and 2010. To combine these data sources, we used an integrated Bayesian model that allowed us to account for the process and measurement errors associated with each... |
| Tipo: Text |
Palavras-chave: Indian Ocean yellowfin; Hierarchical Bayesian model; Tagging; Fisheries. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00254/36513/35080.pdf |
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| Pinto, Cecilia; Travers-trolet, Morgane; Macdonald, Jed; Rivot, Etienne; Vermard, Youen. |
| The biological status of many commercially-exploited fishes remains unknown, mostly due to a lack of data necessary for their assessment. Investigating the spatio-temporal dynamics of such species can lead to new insights into population processes, and foster a path towards improved spatial management decisions. Here, we focused on striped red mullet (Mullus surmuletus), a widespread, yet data-limited species of high commercial importance. Aiming to quantify range dynamics in this data-poor scenario, we combined fishery-dependent and -independent datasets through a series of Bayesian mixed-effects models designed to capture monthly and seasonal occurrence patterns near the species’ northern range limit across 20 years. Combining multiple datasets allowed... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00460/57187/59150.pdf |
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| Rochette, Sebastien; Huret, Martin; Rivot, Etienne; Le Pape, Olivier. |
| For many marine fish species, recruitment is strongly related to larval survival and dispersal to nursery areas. Simulating larval drift should help assessing the sensitivity of recruitment variability to early life history. An individual-based model (IBM) coupled to a hydrodynamic model was used to simulate common sole larval supply from spawning areas to coastal and estuarine nursery grounds at the population scale in the eastern Channel on a 14-yr time series, from 1991 to 2004. The IBM allowed each particle released to be transported by currents from the hydrodynamic model, to grow with temperature, to migrate vertically giving stage development, and possibly to die according to drift duration, representing the life history from spawning to... |
| Tipo: Text |
Palavras-chave: Eastern Channel; Hydrodynamic model; Individual-based model; Larval supply; Nursery grounds; Recruitment variability; Solea solea. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00085/19598/17236.pdf |
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| Rochette, S.; Rivot, Etienne; Morin, Jocelyne; Mackinson, S.; Riou, Philippe; Le Pape, Olivier. |
| Estuaries and coastal waters are essential nursery habitats for many marine species, and especially for flatfishes. Thus, investigating how anthropogenic disturbances affect the quality of these habitats is of major importance to understand their consequences on the population renewal of marine species. The aim of the present study was to analyse the effects of estuarine habitat degradation on the population of the common sole in the Eastern Channel, a key species in the fish community and fisheries in this area. We especially focused on the drastic drop in the surface area and on the low water quality of the Seine estuary, the main river of the Eastern Channel. A geographic Information System (GIS) was used to develop quantitative maps of sole nursery... |
| Tipo: Text |
Palavras-chave: Solea solea; Nursery; Habitat Mapping; Anthropogenic Disturbance; Seine Estuary; Recruitment. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00008/11921/9799.pdf |
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| Bonhommeau, Sylvain; Blanke, Bruno; Treguier, Anne-marie; Grima, Nicolas; Rivot, Etienne; Vermard, Youen; Greiner, Eric; Le Pape, Olivier. |
| The migration duration of European eel (Anguilla anguilla) larvae (leptocephali) from the spawning areas in the Sargasso Sea to the European continental shelf remains highly controversial, with estimates varying from 6 months to more than 2 yr. We estimated the fastest migration period and the shortest distance travelled by eel larvae by simulating Lagrangian particles released in the Sargasso Sea and by simulating a range of larval behaviours (fixed-depth drift, vertical diurnal migration and active-depth selection to maximize current velocity). This enabled us to compute (i) a passive drift speed, and (ii) a hypothetic swimming speed needed for European eel larvae to cross the Atlantic in 6 months (i.e., the migration duration estimated from otolith... |
| Tipo: Text |
Palavras-chave: Sargasso Sea; Migration duration; Leptocephali; Lagrangian modelling; Gulf Stream; Fractals; Anguilla. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6865.pdf |
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| 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 |
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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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| Rivot, Etienne; Charuau, Anatole; Rose, Joel; Achoun, Joseph. |
| En Guyane française , le vivaneau rouge (Lutjanus purpureus) est capturé par 3 flottilles, les ligneurs vénézuéliens, les caseyeurs antillais et les chalutiers crevettiers guyanais. Pour les crevettiers, il s'agit d'une capture accessoire inévitable, mais qui ne semble pas sans conséquences, puisque, si l'on tient compte de l'effectif total de la flottille, c'est 1 million à 1.5 millions de juvéniles qui sont pêchés (et souvent rejetés à la mer) annuellement par les crevettiers. Pour les ligneurs vénézuéliens qui pêchent 1200 tonnes, les individus de petite taille sont devenus prépondérants dans leurs captures. Ainsi dans la gamme de taille 20-30cm (125-425 grammes), on est passé, entre 1990 et 1998, de 37 000 poissons débarqués (6% de la capture) à 616... |
| Tipo: Text |
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| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00075/18614/16167.pdf |
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| 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 |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00223/33377/31802.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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| 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 |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00515/62634/67003.pdf |
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| Registros recuperados: 24 | |
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