Consulta: creatorFacets:"Gascuel, Didier"
Registros recuperados: 22
Data/hora: 01/06/2024 13:34:31

Combining ecosystem indicators and life cycle assessment for environmental assessment of demersal trawling in Tunisia
Provedor de dados: 5
Autores: Abdou, Khaled; Le Loc'H, Francois; Gascuel, Didier; Romdhane, Mohamed Salah; Aubin, Joel; Ben Rais Lasram, Frida.
Purpose The present study assesses environmental performance of seafood production by demersal trawling in Tunisia (Gulf of Gabes) in order to analyze the contribution of each production stage to environmental impacts and to understand drivers of the impacts using life cycle assessment (LCA). Then a set of ecosystem quality indicators were determined using an ecosystem modeling tool, Ecopath with Ecosim (EwE), and were combined with LCA to increase the relevance of both tools' assessments when applied to fisheries. Methods The approach consisted of conducting LCA and calculating ecosystem indicators to provide a complete assessment of trawling's environmental impacts and the ecosystem characteristics associated with seafood production. The functional unit...
Tipo: Text
Palavras-chave: Life cycle assessment; Fisheries; Ecosystem modeling; Ecopath with Ecosim; Ecospace; Demersal trawling; Environmental impacts; Gulf of Gabes.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00609/72148/70895.pdf

Integrated ecological-economic fisheries models-Evaluation, review and challenges for implementation
Provedor de dados: 5
Autores: 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

The Impact of Fisheries Discards on Scavengers in the Sea
Provedor de dados: 5
Autores: Depestele, Jochen; Feekings, Jordan; Reid, David G; Cook, Robin; Gascuel, Didier; Girardin, Raphael; Heath, Michael; Hernvann, Pierre-yves; Morato, Telmo; Soszynski, Ambre; Savina-rolland, Marie.
A scavenger is an animal that feeds on dead animals (carrion) that it has not killed itself. Fisheries discards are often seen as an important food source for marine scavengers so the reduction of discards due to the Landing Obligation may affect their populations. The literature on scavenging in marine ecosystems is considerable, due to its importance in the trophic ecology of many species. Although discards undoubtedly contribute to these species’ food sources, few can be seen to be solely dependent on carrion (including discards). Ecosystem models predicted that discards contributed very little to the diet of scavengers at a regional scale. A reduction in discards through the Landing Obligation may therefore affect populations for a few species in some...
Tipo: Text
Palavras-chave: Carrion; Discard consumption; Food subsidies; Food web models; Scavengers.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00473/58436/61011.pdf

Long-term fishing impact on the Senegalese coastal demersal resources: diagnosing from stock assessment models
Provedor de dados: 5
Autores: Ba, Kamarel; Thiaw, Modou; Fall, Massal; Thiam, Ndiaga; Meissa, Beyah; Jouffre, Didier; Thiaw, Omar Thiom; Gascuel, Didier.
For the first time in Senegal, assessments based on both stochastic and deterministic production models were used to draw a global diagnosis of the fishing impact on coastal demersal stocks. Based one national fisheries databases and scientific trawl surveys data: (i) trends in landings since 1971 were examined, (ii) abundance indices of 10 stocks were estimated using linear models fitted to surveys data and commercial catch per unit efforts, and (iii) stock assessments were carried out using pseudo-equilibrium Fox and Pella-Tomlinson models and a Biomass dynamic production model fitted in a Bayesian framework to abundance indices. Most stocks have seen their abundance sharply declining over time. All stocks combined, results of stock assessments suggest a...
Tipo: Text
Palavras-chave: Coastal demersal species; Delta-GLM models; Surplus production models; Bayesian approach; Overexploitation; West Africa.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00626/73792/74929.pdf

Global marine primary production constrains fisheries catches
Provedor de dados: 5
Autores: Chassot, Emmanuel; Bonhommeau, Sylvain; Dulvy, Nicholas K.; Melin, Frederic; Watson, Reg; Gascuel, Didier; Le Pape, Olivier.
Primary production must constrain the amount of fish and invertebrates available to expanding fisheries; however the degree of limitation has only been demonstrated at regional scales to date. Here we show that phytoplanktonic primary production, estimated from an ocean-colour satellite (SeaWiFS), is related to global fisheries catches at the scale of Large Marine Ecosystems, while accounting for temperature and ecological factors such as ecosystem size and type, species richness, animal body size, and the degree and nature of fisheries exploitation. Indeed we show that global fisheries catches since 1950 have been increasingly constrained by the amount of primary production. The primary production appropriated by current global fisheries is 17-112% higher...
Tipo: Text
Palavras-chave: Bottom-up; Large Marine Ecosystem; Quantile regression; Sustainable fishing.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00002/11294/7836.pdf

Evaluating changes in marine communities that provide ecosystem services through comparative assessments of community indicators
Provedor de dados: 5
Autores: Kleisner, Kristin M.; Coll, Marta; Lynam, Christopher P.; Bundy, Alida; Shannon, Lynne; Shin, Yunne-jai; Boldt, Jennifer L.; Borges, Maria F.; Diallo, Ibrahima; Fox, Clive; Gascuel, Didier; Heymans, Johanna J.; Juan Jorda, Maria J.; Jouffre, Didier; Large, Scott I.; Marshall, Kristin N.; Ojaveer, Henn; Piroddi, Chiara; Tam, Jorge; Torres, Maria A.; Travers-trolet, Morgane; Tsagarakis, Konstantinos; Van Der Meeren, Gro I.; Zador, Stephani.
Fisheries provide critical provisioning services, especially given increasing human population. Understanding where marine communities are declining provides an indication of ecosystems of concern and highlights potential conflicts between seafood provisioning from wild fisheries and other ecosystem services. Here we use the nonparametric statistic, Kendall׳s tau, to assess trends in biomass of exploited marine species across a range of ecosystems. The proportion of ‘Non-Declining Exploited Species’ (NDES) is compared among ecosystems and to three community-level indicators that provide a gauge of the ability of a marine ecosystem to function both in provisioning and as a regulating service: survey-based mean trophic level, proportion of predatory fish,...
Tipo: Text
Palavras-chave: Ecological indicator; Comparative approach; Community metric; IndiSeas; Fishing impacts.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00254/36555/35186.pdf

Les prises accessoires effectuees lors de la peche de la Civelle d'anguille (Anguilla anguilla L.), Etude preliminaire en Loire et en Vilaine.
Provedor de dados: 5
Autores: Gascuel, Didier; Elie, Pierre.
The study of 41 samples, which were perfomed in the Loire and Vilaine estuaries, during elver fishing seasons 1979-80 and 1980-81, allowed us to define a rapid method of sample analysis in laboratory. The fish catches of one-year old and over were not abundant (eel, mullet, sprat, flounder, sole); on the other hand, larval stages of herring, flounder and also of mullet, sole and sprat were caught in large quantities. In addition, there were numerous catches of brown shrimp and species of trophic interest such as goby and macroplanktonic crustaceans. It is noteworthy that the by-catches are numerous during the fishing season.
Tipo: Text
Palavras-chave: Anguilla anguilla; Fishery statistics.
Ano: 1982
URL: http://archimer.ifremer.fr/doc/1982/publication-1882.pdf

Carrières d'halieutes. Histoires de mer et de passions
Provedor de dados: 5
Autores: Gascuel, Didier.
Qui n’a jamais rêvé de parcourir le monde et d’être au cœur de l’action ? de survoler en hélicoptère la mer Rouge ou de parcourir l’Algérie en quête de sites de pêche ? Pour les ambitieux, que diriez-vous d’être promu consultant en Iran, commissaire du gouvernement ? Pour les combatifs, et si à Bruxelles vous dédiiez vos nuits aux pêcheurs en colère ? Pour ceux qui aiment les défis, et si demain sous un soleil brûlant on vous nommait secrétaire général d’un syndicat d’armateurs à la pêche industrielle au Congo pour faire des miracles ? Pour les diplomates, que feriez-vous si le président de la République centrafricaine vous demandait de construire un pipeline long de 2 000 km pour élever des crevettes marines en pleine forêt ? Pour les âmes humanitaires,...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00663/77525/79333.pdf

Identifying fishing trip behaviour and estimating fishing effort from VMS data using Bayesian Hidden Markov Models
Provedor de dados: 5
Autores: 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

An ecosystem approach for the assessment of fisheries impacts on marine top predators: the Bay of Biscay case study
Provedor de dados: 5
Autores: Lassalle, Geraldine; Gascuel, Didier; Le Loch, Francois; Lobry, Jeremy; Pierce, Graham John; Ridoux, Vincent; Santos, Maria Begona; Spitz, Jerome; Niquil, Nathalie.
A number of marine mammal populations is currently threatened by their interactions with fisheries. The present study aimed to provide insights into the severity of potential impacts of operational and biological interactions between top predators and fisheries, in the Bay of Biscay region. Our approach was to modify an Ecopath with Ecosim (EwE) model describing the overall structure and function of the ecosystem by including landings and discards of exploited stocks and estimations of the bycatch of non-target compartments. Second, a set of ecological indices and a trophic level (TL)-based model (EcoTroph, ET) were derived from the EwE model. ET was used to simulate the effects of increasing fishing pressure on the ecosystem and, more particularly, on top...
Tipo: Text
Palavras-chave: Ecopath; Ecosystem modelling; EcoTroph; Fisheries impacts; Marine mammals; Trophic level.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00087/19855/17541.pdf

Towards the implementation of an integrated ecosystem fleet-based management of European fisheries
Provedor de dados: 5
Autores: Gascuel, Didier; Merino, G.; Doering, R.; Druon, Jean-noel; Goti, L.; Guenette, S.; Macher, Claire; Soma, K.; Travers-trolet, Morgane; Mackinson, Steve.
Using the Celtic Sea and the North Sea as case studies, the fleet-based approach is shown to be the pathway to implement an effective ecosystem approach to fisheries management (EAFM) in European seas. First, a diagnostic on the health of each ecosystem is proposed based on the reconstruction of long time-series of catch, the analysis of mean indicators or stocks trajectories derived from ICES stock assessment results, and the analysis of ecosystem indicators. Then, a fleet-based synthesis is presented using indicators of both the ecological impact and the economic performances of the major fleets operating within each ecosystem. In particular, assessment diagrams show whether each fleet segment, on average, sustainably exploits the stocks. Although...
Tipo: Text
Palavras-chave: Ecosystem approach; Economic performance; Fisheries management; Fleet; Indicator; Sustainable development.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00075/18601/16179.pdf

The Celtic Sea Through Time and Space: Ecosystem Modeling to Unravel Fishing and Climate Change Impacts on Food-Web Structure and Dynamics
Provedor de dados: 5
Autores: Hernvann, Pierre-yves; Gascuel, Didier; Grüss, Arnaud; Druon, Jean-noël; Kopp, Dorothee; Perez, Ilan; Piroddi, Chiara; Robert, Marianne.
Both trophic structure and biomass flow within marine food webs are influenced by the abiotic environment and anthropogenic stressors such as fishing. The abiotic environment has a large effect on species spatial distribution patterns and productivity and, consequently, spatial co-occurrence between predators and prey, while fishing alters species abundances and food-web structure. In order to disentangle the impacts of the abiotic environment and fishing in the Celtic Sea ecosystem, we developed a spatio-temporal trophic model, specifically an Ecopath with Ecosim with Ecospace model, for the period 1985–2016. In this model, particular attention was paid to the parameterization of the responses of all trophic levels to abiotic environmental changes....
Tipo: Text
Palavras-chave: Celtic Sea; Ecosystem modeling; Habitat model; Environment; Ecopath with Ecosim and Ecospace; Primary production; Fishing impact.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00662/77419/79084.pdf

The need for a protean fisheries science to address the degradation of exploited aquatic ecosystems
Provedor de dados: 5
Autores: Drouineau, Hilaire; Lobry, Jeremy; Bez, Nicolas; Travers-trolet, Morgane; Vermard, Youen; Gascuel, Didier.
In this introductory paper we highlight key questions that were discussed during the symposium on “Status, functioning and shifts in marine ecosystems” organized by the Association Française d’Halieutique (French Association for Fisheries Sciences, Montpellier, France, July 2015). This symposium illustrated that fisheries science is now working at multiple scales and on all dimensions of socio-ecosystems (ecological, political, sociological, and economic), with a great diversity of approaches and taking into account different levels of complexity while acknowledging diverse sources of uncertainty. We argue that we should go one step further and call for a protean fisheries science to address the deteriorated states of aquatic ecosystems caused by...
Tipo: Text
Palavras-chave: EAFM; Fisheries management; Fisheries science; Marine resources; Models; Uncertainty.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00359/46990/46921.pdf

Trophic models: What do we learn about Celtic Sea and Bay of Biscay ecosystems?
Provedor de dados: 5
Autores: Moullec, Fabien; Gascuel, Didier; Bentorcha, Karim; Guenette, Sylvie; Robert, Marianne.
Trophic models are key tools to go beyond the single-species approaches used in stock assessments to adopt a more holistic view and implement the Ecosystem Approach to Fisheries Management (EAFM). This study aims to: (i) analyse the trophic functioning of the Celtic Sea and the Bay of Biscay, (ii) investigate ecosystem changes over the 1980–2013 period and, (iii) explore the response to management measures at the food web scale. Ecopath models were built for each ecosystem for years 1980 and 2013, and Ecosim models were fitted to time series data of biomass and catches. EcoTroph diagnosis showed that in both ecosystems, fishing pressure focuses on high trophic levels (TLs) and, to a lesser extent, on intermediate TLs. However, the interplay between local...
Tipo: Text
Palavras-chave: Ecosystem Approach to Fisheries Management (EAFM); Bay of Biscay; Celtic Sea; Ecopath with Ecosim; EcoTroph; Trophic indicators.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00377/48771/49169.pdf

Are we ready to track climate‐driven shifts in marine species across international boundaries? ‐ A global survey of scientific bottom trawl data
Provedor de dados: 5
Autores: Maureaud, Aurore; Frelat, Romain; Pécuchet, Laurène; Shackell, Nancy; Mérigot, Bastien; Pinsky, Malin L.; Amador, Kofi; Anderson, Sean C.; Arkhipkin, Alexander; Auber, Arnaud; Barri, Iça; Bell, Richard J.; Belmaker, Jonathan; Beukhof, Esther; Camara, Mohamed L.; Guevara‐carrasco, Renato; Choi, Junghwa; Christensen, Helle T.; Conner, Jason; Cubillos, Luis A.; Diadhiou, Hamet D.; Edelist, Dori; Emblemsvåg, Margrete; Ernst, Billy; Fairweather, Tracey P.; Fock, Heino O.; Friedland, Kevin D.; Garcia, Camilo B; Gascuel, Didier; Gislason, Henrik; Goren, Menachem; Guitton, Jérôme; Jouffre, Didier; Hattab, Tarek; Hidalgo, Manuel; Kathena, Johannes N.; Knuckey, Ian; Kidé, Saïkou O.; Koen‐alonso, Mariano; Koopman, Matt; Kulik, Vladimir; León, Jacqueline P; Levitt‐barmats, Ya’arit; Lindegren, Martin; Llope, Marcos; Massiot‐granier, Félix; Masski, Hicham; Mclean, Matthew; Meissa, Beyah; Mérillet, Laurene; Mihneva, Vesselina; Nunoo, Francis K. E.; O'Driscoll, Richard; O'Leary, Cecilia A.; Petrova, Elitsa; Ramos, Jorge E.; Refes, Wahid; Román‐marcote, Esther; Siegstad, Helle; Sobrino, Ignacio; Sólmundsson, Jón; Sonin, Oren; Spies, Ingrid; Steingrund, Petur; Stephenson, Fabrice; Stern, Nir; Tserkova, Feriha; Tserpes, Georges; Tzanatos, Evangelos; Rijn, Itai; Zwieten, Paul A. M.; Vasilakopoulos, Paraskevas; Yepsen, Daniela V.; Ziegler, Philippe; Thorson, James.
Marine biota are redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of data availability, and mismatch between data and real species distributions. To assess the extent of this challenge, we review the global status and accessibility of ongoing scientific bottom trawl surveys. In total, we gathered metadata for 283,925 samples from 95 surveys conducted regularly from 2001 to 2019. We identified that 59% of the metadata collected are not publicly available, highlighting that the...
Tipo: Text
Palavras-chave: Bottom trawl survey; Climate change; Demersal fish; Fisheries policy; Global data synthesis; Open science; Species distribution; Transboundary conservation.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00658/76971/78197.pdf

An iron cycle cascade governs the response of equatorial Pacific ecosystems to climate change
Provedor de dados: 5
Autores: Tagliabue, Alessandro; Barrier, Nicolas; Du Pontavice, Hubert; Kwiatkowski, Lester; Aumont, Olivier; Bopp, Laurent; Cheung, William W. L.; Gascuel, Didier; Maury, Olivier.
Earth System Models project that global climate change will reduce ocean net primary production (NPP), upper trophic level biota biomass and potential fisheries catches in the future, especially in the eastern equatorial Pacific. However, projections from Earth System Models are undermined by poorly constrained assumptions regarding the biological cycling of iron, which is the main limiting resource for NPP over large parts of the ocean. In this study, we show that the climate change trends in NPP and the biomass of upper trophic levels are strongly affected by modifying assumptions associated with phytoplankton iron uptake. Using a suite of model experiments, we find 21st century climate change impacts on regional NPP range from −12.3% to +2.4% under a...
Tipo: Text
Palavras-chave: Climate change; Iron; Marine ecosystems; Net primary production; Ocean.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00652/76417/77470.pdf

Fishing impact and environmental status in European seas: a diagnosis from stock assessments and ecosystem indicators
Provedor de dados: 5
Autores: Gascuel, Didier; Coll, Marta; Fox, Clive; Guenette, Sylvie; Guitton, Jerome; Kenny, Andrew; Knittweis, Leyla; Nielsen, J. Rasmus; Piet, Gerjan; Raid, Tiit; Travers-trolet, Morgane; Shephard, Samuel.
Stock-based and ecosystem-based indicators are used to provide a new diagnosis of the fishing impact and environmental status of European seas. In the seven European marine ecosystems covering the Baltic and the North-east Atlantic, (i) trends in landings since 1950 were examined; (ii) syntheses of the status and trends in fish stocks were consolidated at the ecosystem level; and (iii) trends in ecosystem indicators based on landings and surveys were analysed. We show that yields began to decrease everywhere (except in the Baltic) from the mid-1970s, as a result of the over-exploitation of some major stocks. Fishermen adapted by increasing fishing effort and exploiting a wider part of the ecosystems. This was insufficient to compensate for the decrease in...
Tipo: Text
Palavras-chave: Ecosystem approach to fisheries management; Ecosystem indicators; Good environmental status; Marine Strategy Framework Directive; Stock assessment; Trophic level.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00201/31256/29910.pdf

Trophic level-based indicators to track fishing impacts across marine ecosystems
Provedor de dados: 5
Autores: Shannon, Lynne; Coll, Marta; Bundy, Alida; Gascuel, Didier; Heymans, Johanna J;; Kleisner, Kristin; Lynam, Christopher; Piroddi, Chiara; Tam, Jorge; Travers-trolet, Morgane; Shin, Yunne.
Trophic level (TL)-based indicators have been widely used to examine fishing impacts in aquatic ecosystems and the induced biodiversity changes. However, much debate has ensued regarding discrepancies and challenges arising from the use of landings data from commercial fisheries to calculate TL indicators. Subsequent studies have started to examine survey-based and model-based indicators. In this paper, we undertake an extensive evaluation of a variety of TL indicators across 9 well-studied marine ecosystems by making use of model- as well as surveyand catch-based TL indicators. Using detailed regional information and data on fishing history, fishing intensity, and environmental conditions, we evaluate how well TL indicators are capturing fishing effects...
Tipo: Text
Palavras-chave: Trophic level; Global comparison; Indicator; Survey; Catch; Ecosystem model; Trophic spectra; Convention on Biological Diversity; Food webs; Ecosystem approach to fisheries.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00222/33361/31768.pdf

EcoTroph: a simple model to assess fishery interactions and their impacts on ecosystems
Provedor de dados: 5
Autores: Gasche, Loic; Gascuel, Didier.
The EcoTroph model leaves aside the notion of species, and models the functioning of marine ecosystems as flows of biomass from low to high trophic levels, so as to quantify easily the impacts of fishing at an ecosystem scale. In this paper, based on two case studies we present a new development of the EcoTroph model that is devoted to the analysis of fishery interactions and impacts of fleet segments on ecosystems. First, deriving an EcoTroph model from an Ecopath model of the Guinea ecosystem, the impacts of the artisanal fishery are distinguished from those of the industrial fishery. It appears that these fisheries do not always compete for the same fish groups but that they both strongly impact the ecosystem and moderately impact one another. Then, an...
Tipo: Text
Palavras-chave: Ecopath; Ecosystem modelling; EcoTroph; Fishery interactions; Fishing impact; Guinea; Management scenario; Small pelagics; Southern Benguela.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00138/24970/23123.pdf

Estimation of technical interactions due to the competition for resource in a mixed-species fishery, and the typology of fleets and metiers in the English Channel
Provedor de dados: 5
Autores: Ulrich, Clara; Gascuel, Didier; Dunn, Matthew R; Le Gallic, Bertrand; Dintheer, Christian.
In a multi-gear and multi-species artisanal fishery, the level of technical interactions (i.e. the competitive externalities resulting from a shared exploitation of common resources or fishing grounds) among various fishing units is high. Assessing these technical interactions is of great importance for fishery management, as any control applied to one fishing unit may have positive or negative effects on others. The magnitude and direction of these effects cannot be easily measured, unless all fishing units and species in the fishery are considered simultaneously. Technical interactions are particularly important in the complex artisanal fisheries of the English Channel. Using a bioeconomic model of the English Channel that incorporates all the major...
Tipo: Text
Palavras-chave: Modèle bioéconomique; Compétition; Externalités de stock; Interactions techniques; Typologie; Manche; Bioeconomic model; Competition; Stock externalities; Technical interactions; Typology; English Channel.
Ano: 2001
URL: https://archimer.ifremer.fr/doc/00187/29874/28363.pdf

Exploring the impacts of fishing and environment on the Celtic Sea ecosystem since 1950
Provedor de dados: 5
Autores: Hernvann, Pierre-yves; Gascuel, Didier.
Analyzing the long-term changes in ecosystems and disentangling the influence of overfishing and environment require historical data integration. Fisheries-independent data are available only since the mid-1980s in the Celtic Sea and thus provide a short-term and truncated vision of fishing impacts. We conducted a catch-based study over the 1950–2015 period. We successively (i) reconstituted catch time-series, including unreported catch estimates, and studied them through a trophic-spectrum approach and ecosystem indicators based on trophic level, size and species diversity; (ii) estimated biomass trends of the main Celtic Sea target species from catch and effort time-series, using production models that detect potential shifts in productivity; and (iii)...
Tipo: Text
Palavras-chave: Fishing impact; Celtic Sea; Catch reconstruction; Biomass production model; Ecosystem regime shifts; Trophic cascade; Fish productivity.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00600/71241/73090.pdf

Combining fleet dynamics and population dynamics for a volatile fishery: the example of the anchovy fishery of the Bay of Biscay
Provedor de dados: 5
Autores: 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...
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00107/21858/19449.pdf