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| Registros recuperados: 152 | |
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| Priour, Daniel. |
| Measurements at sea during fishing trials on bottom trawl, have revealed that the geometry of the trawl is affected by the catch. A series of 27 hauls of around 3h have been carried out during the EFFICHALUT project. This project aimed to find out improvements on the fishing gear in order to reduce the energy consumption. For this project numerous sensors have been used, for bridles tension, doors spread, vertical opening, doors attitude. The measurements show quite clearly that the doors spread decreases and the bridles tension increases along most of the hauls. The doors spread decreases by 1.35m per hour, with a standard deviation of 1.98m/h when the top bridle tension increases of 47kg/h, with a standard deviation of 59kg/h. The mean catch per haul is... |
| Tipo: Text |
Palavras-chave: Trawl; Data; Modelling; Doors spread; Bridle tension; Catch weight. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00186/29761/28208.pdf |
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| Orvain, Francis; Sauriau, Pierre-guy. |
| Laboratory microcosms were used to investigate the mud snail Hydrobia ulvac (Pennant) bioturbation activities and behavioural changes in response to snail density, algal food, sediment moisture content, light regime and water cover conditions. Density-dependent kinetics of bioturbated muddy areas were described by von Bertalanffy equations, which provided reliable estimates of mud surface covering rates by snail tracks (m(2) h(-1) snail(-1)), Snails need a wet habitat to be active either covered by seawater or by moving in fluid layers for low-tide conditions. Light and microphytobenthic biomass, which are less potent to affect snail activity, are positively interrelated to increase covering rates in the tested chl a concentrations within the range of 1 -... |
| Tipo: Text |
Palavras-chave: Modelling; Intertidal mudflat; Hydrobia ulvae; Environmental factors; Bioturbation; Behaviour. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/publication-3775.pdf |
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| Priour, Daniel. |
| Trawls energy efficiency is greatly affected by the drag, as well as by the swept area regarding pelagic trawls and by the swept width for bottom ones. The drag results in an increase of the energy consumption and the sweeping influences the catch. In order to reduce the drag per swept area (or width) a numerical tool dedicated to the automatic optimisation of the trawl design has been developed. Based on a finite element method model for flexible netting structures, the tool modifies step by step a reference design. For each step the best-modified design, in terms of drag per swept area (or width), is kept. Such a methodology was used in two cases: which show a 43% increase in energy efficiency regarding the pelagic trawl case and 27% for the bottom trawl... |
| Tipo: Text |
Palavras-chave: Swept width; Swept area; Drag; Fuel consumption; Optimisation; Modelling; Trawl; Fishing gears. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6583.pdf |
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| Martinez, Carlos; Mairet, Francis; Bernard, Olivier. |
| Microalgae can be cultivated in closed or open photobioreactors (PBR). In these systems, light rapidly decreases as it passes through the culture due to the turbidity of the medium. Thus, microalgae experiment different light intensities depending on their position in the medium. In this paper, we study theoretically how the growth rate of microalgae is affected by different factors; incident light intensity, form of the PBR, microalgae population density, turbidity of non-microalgae components, and light path-length of the reactor. We show that for different types of PBR the average growth rate is completely determined by the incident light intensity and the optical depth. In the case of vertical cylindrical PBRs illuminated from above (e.g. race-way or... |
| Tipo: Text |
Palavras-chave: Photobioreactor; Optical depth; Photoinhibition; Light limitation; Turbidity; Modelling. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00450/56133/57675.pdf |
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| Martin, Corinne; Vaz, Sandrine; Koubbi, Philippe; Meaden, Geoff; Engelhard, Georg H.; Lauria, Valentina; Gardel, Laure; Coppin, Franck; Delavenne, Juliette; Dupuis, Ludovic; Ernande, Bruno; Foveau, Aurelie; Lelievre, Stephanie; Morin, Jocelyne; Warembourg, Caroline; Carpentier, Andre. |
| The eastern English Channel, which connects the Atlantic Ocean to the North Sea through the Dover Strait, is an area where numerous and often conflicting human activities take place. A cross-border multidisciplinary project called CHARM was initiated to provide knowledge and tools for planners and decision-makers to durably manage the shared marine living resources. One such tool was an atlas of fish spatial distributions and modelled habitats, which was used here to investigate ontogenic and seasonal shifts in fish spatial distribution and habitat through a case-study, the dab Limanda limanda. Survey data for several life-history stages (eggs, larvae, coastal nurseries, < and > 1 year old) and seasons were used to map spatial patterns (using... |
| Tipo: Text |
Palavras-chave: Pleuronectidae; Limanda limanda; Eastern Channel; Spatial distribution; Modelling; Kriging; Ichthyoplankton; Trawl; CUFES. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00008/11942/8646.pdf |
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| Lasserre, Pierre. |
| Coordinated ECOTRON Program on the Arcachon Basin (Aquitaine, France) : Control of marine biological production in a man-modified lagoon ecosystem (fish ponds). Results, synthesis and prospects. The "fish reservoirs" of the Arcachon Basin consist of eutrophic lagoon ecosystems, empirically exploited for extensive amphihaline fish culture (grey mullets, sea bass, eels, sea breams). The 1000 hectares of exploited farms, well integrated in a traditional socio-economic context, are presently not adapted for various reasons.The coordinate researches, which have been developed at Arcachon since 1974, within the ECOTRON (CNEXO) Program, show that these highly productive man modified ecosystems are well adapted for the development of semi-intensive aquaculture.... |
| Tipo: Text |
Palavras-chave: Lagunes côtières exploitées; Réservoirs à poissons; Bassin d'Arcachon; Fonctionnement écosystème; Contrôle productivité; Modélisation; Développement potentiel; Exploited coastal lagoons; Fish ponds; Arcachon Bay; Ecosystem functioning; Productivity control; Modelling; Potential development. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00306/41676/40885.pdf |
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| Duffa, Celine; Du Bois, Pascal Bailly; Caillaud, Matthieu; Charmasson, Sabine; Couvez, Celine; Didier, Damien; Dumas, Franck; Fievet, Bruno; Morillon, Mehdi; Renaud, Philippe; Thebault, Herve. |
| The Fukushima nuclear accident resulted in the largest ever accidental release of artificial radionuclides in coastal waters. This accident has shown the importance of marine assessment capabilities for emergency response and the need to develop tools for adequately predicting the evolution and potential impact of radioactive releases to the marine environment. The French Institute for Radiological Protection and Nuclear Safety (IRSN) equips its emergency response centre with operational tools to assist experts and decision makers in the event of accidental atmospheric releases and contamination of the terrestrial environment. The on-going project aims to develop tools for the management of marine contamination events in French coastal areas. This should... |
| Tipo: Text |
Palavras-chave: Decision support; Marine; Modelling; Radioecology; Nuclear accident. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00270/38118/36480.pdf |
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| Sultan, Nabil; Voisset, Michel; Marsset, Bruno; Marsset, Tania; Cauquil, E; Colliat, J. |
| The study area, offshore Nigeria, is located in one of the compressional zones within the Niger Delta, which is characterized by imbricate thrust structures. Although the low mean slope angle (around 2°), bathymetry data from the study area have shown the existence of several submarine landslides which coincide with known subsurface faulted compressive features. In this paper, we have focused on a submarine slide occurring in water depths ranging between 1690 and 1750 m. Headwall scars, internal architecture and associated deposits have been characterized using a combination of 3D seismic data, near-bottom echosounder seismic profiles, Kullenberg cores and in-situ geotechnical measurements. The slide shows horseshoe shaped headwall scars and depositional... |
| Tipo: Text |
Palavras-chave: Slope stability; Piezometer; Penetrometer; Niger Delta; Modelling; Compressional structures. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2408.pdf |
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| Registros recuperados: 152 | |
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