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| Registros recuperados: 64 | |
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| Cormon, Xochitl; Kempf, Alexander; Vermard, Youen; Vinther, Morten; Marchal, Paul. |
| During the last 15 years, northern European hake (Merluccius merluccius) has increased in abundance, and its spatial distribution has expanded in the North Sea region in correlation with temperature. In a context of global warming, this spatial shift could impact local trophic interactions: direct impacts may affect forage fish through modified predator–prey interactions, and indirect impacts may materialize through competition with other resident predators. For instance, North Sea saithe (Pollachius virens) spatial overlap with hake has increased while saithe spawning-stock biomass has decreased recently notwithstanding a sustainable exploitation. In this context, we investigated the range of potential impacts resulting from most recent hake emergence in... |
| Tipo: Text |
Palavras-chave: Hake; Interspecific competition; Maximum sustainable yield; Multispecies stock assessment; Norway pout; Predator-prey interactions; Saithe; Simple foodweb; SMS. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00327/43794/45917.pdf |
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| Di Pane, Julien; Gendrot, F.; Giraldo, Carolina; Marchal, Paul; Koubbi, Philippe; Loots, Christophe. |
| In the present study, the histological-based condition of common sole (Solea solea) larvae in the English Channel was evaluated to assess the relevance of experimentally-calibrated indices for wild collected specimens. Based on topographical observation of foregut, midgut, hindgut, liver and pancreas, each of the 202 larvae analysed was attributed one of the six grades of a condition index that was developed for sole in the nineties. In parallel, a synthetic table of 20 criteria historically used as condition indicators was created from an extensive review of the literature. These criteria were related to tissular integrity, cells height, nuclei, presence of prey and vacuolisation of the same five target organs. For each larva, each criterion was scored on... |
| Tipo: Text |
Palavras-chave: Condition index; Eastern English Channel; Fish larvae; Histology; Solea solea; Starvation. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00601/71325/69754.pdf |
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| Denis, Jeremy; Vallet, Carole; Vincent, Dorothée; Courcot, Lucie; Marchal, Paul; Loots, Christophe. |
| The aim of this study was to characterize the feeding strategy of Downs herring larvae at "critical period" during winter in the English Channel and North Sea was defined to assess whether nutrition is responsible for low recruitment in stocks over the past years. Data collected during the French part of the International Bottom Trawl Survey from 2008 to 2014 were used to analyse fish larvae diet by direct observation using Scanning Electron Microscope (SEM). Gut content methods generally used for copepods was adapted to fish larvae to assess phytoplankton ingestion. The relative importance of small preys (0,5-375µm) observed in gut contents proved the essential role of SEM to better acknowledge Downs herring diet. We demonstrated that Downs herring larvae... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00255/36608/35174.pdf |
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| Tidd, Alex N.; Vermard, Youen; Marchal, Paul; Pinnegar, John; Blanchard, Julia L.; Milner-gulland, E. J.. |
| The European Union and other states are moving towards Ecosystem Based Fisheries Management to balance food production and security with wider ecosystem concerns. Fishing is only one of several sectors operating within the ocean environment, competing for renewable and non-renewable resources that overlap in a limited space. Other sectors include marine mining, energy generation, recreation, transport and conservation. Trade-offs of these competing sectors are already part of the process but attempts to detail how the seas are being utilised have been primarily based on compilations of data on human activity at large spatial scales. Advances including satellite and shipping automatic tracking enable investigation of factors influencing fishers' choice of... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00254/36518/35064.pdf |
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| Holley, Jean-francois; Marchal, Paul. |
| A typology is presented for the French offshore fleet fishing in the North Atlantic. The investigation was carried out separately for all years between 1985 and 2002. Two methods were combined: PCA and cluster analysis. In 1985, most vessels targeted saithe off western Scotland (vessels from Lorient) and in the northern North Sea (vessels from Boulogne and Fecamp). Then, probably because of the decline in biomass of saithe, some vessels started to target deepwater species from the early 1990s. In 2002, some vessels fished exclusively for saithe (>80%), while others targeted mainly deepwater species. In all, 12 fisheries are identified for the period 1985-2002. Results are given of a preliminary investigation trying to identify the external factors... |
| Tipo: Text |
Palavras-chave: Saithe; Multivariate analyses; Mixed fisheries; Fishing strategy; Fisheries dynamics; Deepwater species. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-384.pdf |
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| Marchal, Paul; Gasche, Loic; Girardin, Raphael; Le Pape, Olivier; Huret, Martin; Mahevas, Stephanie; Travers-trolet, Morgane; Vaz, Sandrine. |
| Considerable research has been conducted in the past 15 years around the Eastern English Channel ecosystem. Data collected since the 1970s on the biotic and abiotic compartments have been collated and mapped out in the mid-2000. This spatially explicit information formed a sound basis to improve knowledge on, and model, the functioning and dynamics of key ecosystem compartments, with a focus on flatfish species and fisheries and their interactions with other sectors of activity (aggregate extractions, maritime traffic). The more recent ongoing works are dedicated to the integration of those processes into several complementary end-to-end ecosystem models. |
| Tipo: Text |
Palavras-chave: Eastern English Channel; Flatfish; Spatial analyses; Ecosystem modelling. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00293/40420/38946.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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| 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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| Marchal, Paul; Andersen, Bo; Caillart, B.; Eigaard, Ole; Guyader, Olivier; Hovgaard, Holger; Iriondo, Ane; Le Fur, Fanny; Sacchi, Jacques; Santurtun, Marina. |
| Face-to-face interviews were conducted to identify the main changes in gear and vessel technology that may have improved the fishing efficiency of a number of French, Danish, and Basque fleets over the past few decades. Important changes include the gradual appearance of twin trawls (Danish and French trawlers) and trammel-nets (French gillnetters), and the increased polyvalence of Basque bottom trawlers. The results suggest that fishing effort descriptors that are not traditionally measured (gear type, groundrope type, length of net used per day, headline length, crew size, number of winch or net drums) may have a substantial impact on catch rates. Adjusting fishing effort using such descriptors may generally improve the relationship between fishing... |
| Tipo: Text |
Palavras-chave: Twin trawls; Technological creep; Groundrope; Generalized linear models; Fishing mortality; Fishing effort; Catch rate. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2611.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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| Bourdaud, Pierre; Travers-trolet, Morgane; Vermard, Youen; Marchal, Paul. |
| Managing mixed fisheries requires understanding fishers’ behaviour to allow predicting future fisheries distribution and impact on marine ecosystems. A new approach was developed to compare fine scale fishing effort distribution of Eastern English Channel (EEC) bottom trawlers, to the monthly- and spatially-resolved abundance distributions of commercial species. First, the added-value of using species-specific spatial overlap metric to quantify effective fishing effort and improve the relationship between fishing effort and fishing mortality was assessed. Second, based on the Ideal Free Distribution (IFD) theory, the species-specific weights given by fishers to different species were estimated by maximizing the overlap between target species assemblage and... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00446/55747/57402.pdf |
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| Bourdaud, Pierre; Travers-trolet, Morgane; Vermard, Youen; Cormon, Xochitl; Marchal, Paul. |
| The objective of this study is to analyse at fine scale the annual, seasonal and spatial distributions of several species in the Eastern English Channel (EEC). On the one hand, data obtained from scientific surveys are not available all year through, but are considered to provide consistent yearly and spatially resolved abundance indices. On the other hand, on-board commercial data do cover the whole year, but generally provide a biased perception of stock abundance. The combination of scientific and commercial catches per unit of effort (CPUEs), standardized using a delta-generalized linear model, allowed to infer spatial and monthly dynamics of fish distributions in the EEC, which could be compared with previous knowledge on their life cycles.... |
| Tipo: Text |
Palavras-chave: Commercial data; Eastern English Channel; Seasonality; Spatial distribution; Survey data. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00387/49805/50385.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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| Janssen, Holger; Bastardie, Francois; Eero, Margit; Hamon, Katell; Hinrichsen, Hans-harald; Marchal, Paul; Nielsen, J. Rasmus; Le Pape, Olivier; Schulze, Torsten; Simons, Sarah; Teal, Lorna R.; Tidd, Alex. |
| The relationship between fisheries and marine spatial planning (MSP) is still widely unsettled. While several scientific studies highlight the strong relation between fisheries and MSP, as well as ways in which fisheries could be included in MSP, the actual integration of fisheries into MSP often fails. In this article, we review the state of the art and latest progress in research on various challenges in the integration of fisheries into MSP. The reviewed studies address a wide range of integration challenges, starting with techniques to analyse where fishermen actually fish, assessing the drivers for fishermen's behaviour, seasonal dynamics and long-term spatial changes of commercial fish species under various anthropogenic pressures along their... |
| Tipo: Text |
Palavras-chave: Fisheries; Marine space; Maritime spatial planning; MSP; Marine governance; EBM. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00364/47480/47500.pdf |
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| Marchal, Paul; Poos, Jan-jaap; Quirijns, Floor. |
| This study has investigated some properties of fishermen's foraging, using Levy flights theory. The case studies examined were a selection of North Sea Dutch and French vessels, for which catch and effort data were collected on a haul-by-haul basis. Foraging behavior could reasonably be represented by a Levy flight process, characterized by an exponentiation factor mu, for both fleets. The properties of fishers' foraging were further investigated for the Dutch fleet using time series analysis. Optimal foraging was found with mu = 1.5, suggesting a slow recovery dynamics of the stocks being harvested. Efficient foraging led to high value per unit effort, while the knowledge of fishing grounds with high stock density is shown to increase foraging efficiency... |
| Tipo: Text |
Palavras-chave: Haul by haul data; Foraging; Fishing effort; Levy flights; Fleet behavior. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2314.pdf |
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| Registros recuperados: 64 | |
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