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| Registros recuperados: 129 | |
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| Bauer, Robert; Fromentin, Jean-marc; Demarcq, Herve; Brisset, Blandine; Bonhommeau, Sylvain. |
| Different dolphin and tuna species have frequently been reported to aggregate in areas of high frontal activity, sometimes developing close multi-species associations to increase feeding success. Aerial surveys are a common tool to monitor the density and abundance of marine mammals, and have recently become a focus in the search for methods to provide fisheries-independent abundance indicators for tuna stock assessment. In this study, we present first density estimates corrected for availability bias of fin whales (Balaenoptera physalus) and striped dolphins (Stenella coeruleoalba) from the Golf of Lions (GoL), compared with uncorrected estimates of Atlantic bluefin tuna (ABFT; Thunnus thynnus) densities from 8 years of line transect aerial surveys. The... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00284/39481/37969.pdf |
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| Pierre, Maud; Rouyer, Tristan; Bonhommeau, Sylvain; Fromentin, Jean-marc. |
| Understanding whether recruitment fluctuations in fish stock arise from stochastic forcing (e.g. environmental variations) rather than deterministic forces (e.g. intrinsic dynamics) is a long standing question with important applied consequences for fisheries ecology. In particular, the relationship between recruitment, spawning stock biomass and environmental factors is still poorly understood, even though this aspect is crucial for fisheries management. Fisheries data are often short, but arise from complex dynamical systems with a high degree of stochastic forcing, which are difficult to capture through classic modelling approaches. In the present study, recent statistical approaches based on the approximation of the attractors of dynamical systems are... |
| Tipo: Text |
Palavras-chave: Causality; Forecasting models; Marine. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00408/51930/52555.pdf |
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| Fromentin, Jean-marc. |
| A recent body of literature has demonstrated that older females produce larvae and offsprings that have much higher survival and growth than do younger adults and that they furthermore play a key role in the adaptability, persistence and productivity of the exploited fish populations. These findings, that have been shown for several pelagic, groundfish and rockfish species, are, thus, worth to consider for tuna and tuna-like species. The aim of this modest and brief paper is solely to draw the attention from the SCRS to this issue which may have considerable impacts on management regulations. |
| Tipo: Text |
Palavras-chave: Age structure; Genetic diversity; Recruitment success; Sustainability; Management. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00192/30333/28808.pdf |
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| Fromentin, Jean-marc; Dauvin, Jean-claude; Ibanez, F; Dewarumez, Jean-marie; Elkaim, B. |
| This study examines whether meso-scale meteorological events, in particular the alternation of cold and mild periods, influenced the structure of four Abi cr alba communities, sampled from 1977 to 1992 on the northwest French coast. We propose a new numerical procedure to describe temporal variations in the structure of each assemblage, using some niche-oriented models recently developed by Tokeshi (1993). The description of the temporal changes in the structure of each community was summarized into a 2D-plot of an ordination, performed on observed and simulated patterns. Results showed that important changes occurred in these four assemblages, which were not directly related to the meso-scale climatic events, but mainly to the local environmental factors... |
| Tipo: Text |
Palavras-chave: Macrobenthos community structure species abundance model long-term survey English Channel; North Sea. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20407/18074.pdf |
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| Kaplan, David; Bach, Pascal; Bonhommeau, Sylvain; Chassot, Emmanuel; Chavance, Pierre; Dagorn, Laurent; Davies, Tim; Dueri, Sibylle; Fletcher, Rick; Fonteneau, Alain; Fromentin, Jean-marc; Gaertner, Daniel; Hampton, John; Hilborn, Ray; Hobday, Alistair; Kearney, Robert; Kleiber, Pierre; Lehodey, Patrick; Marsac, Francis; Maury, Olivier; Mees, Chris; Menard, Frederic; Pearce, John; Sibert, John. |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00139/25068/23186.pdf |
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| Fromentin, Jean-marc; Ibanez, F.; Legendre, P.. |
| Multivariate techniques allow data sets to be summarised, but are not deslgned to causally model ecological phenomena. The ambiguity of the interpretation results from the ambiguity of the scaling space. The phytosociological method proposed by Grandjouan (1982; These d'etat, Universite Louis Pasteur, Strasbourg) is a general interpretive framework allowing separate consideration of 3 distinct reference spaces. a geographical space to visualise the spatio-temporal distribution of the descriptors, an ecological space showing the effects of the environmental variables on the biological descriptors, and a bio-ethological space showing the statistically meaningful species cornmunities. It is thus possible to define the position of each biological category and... |
| Tipo: Text |
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| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00033/14454/11756.pdf |
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| Fromentin, Jean-marc. |
| The aim of this study is to investigate the implications of different stock-recruitment assumptions when examining the potential of Dubrovnik’s bluefin tuna recovery plan. To do so, some Beverton and Holt relationships displaying contrasting steepness of 0.99, 0.90, 0.75 and 0.50 were applied within a simulation model. In addition to these four stock-recruitment scenarios, parental effects and stochastic variations were also considered. The main conclusion is that our ability to evaluate the consequences of the Dubrovnik agreement (as any set of management measures) relies on our capacity to predict future recruitment levels in an accurate way. Assuming a Beverton and Holt relationship with different steepness, with or without parental effects and with or... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Management regulations; Stock-recruitment; Parental effects; Stock rebuilding; Simulation model. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00192/30296/28784.pdf |
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| Van Beveren, Elisabeth; Fromentin, Jean-marc; Rouyer, Tristan; Bonhommeau, Sylvain; Brosset, Pablo; Saraux, Claire. |
| Since 2007, the biomass of sardine and anchovy in the NW Mediterranean has remained persistently low, whereas the biomass of the commercially low-valued sprat has exploded. Also, simultaneous decreases in condition, size, and/or age of these populations were observed. Altogether, this resulted in a drop in landings of small pelagics. To understand the amplitude of these events and to provide a baseline scenario against which current changes can be compared, we compiled exceptionally long landing series (1865–2013) of sardine, anchovy, and mackerel for different subregions of the southern French coast. We characterized the fluctuations of these landings and compared these with environmental drivers (sea surface temperature, Rhône river discharge, North... |
| Tipo: Text |
Palavras-chave: Anchovy; Fish landings; Gulf of Lions; Historical time series; Mackerel; Sardine. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00319/43001/42561.pdf |
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| Fromentin, Jean-marc; Rouyer, Tristan. |
| The overexploitation of East Atlantic and Mediterranean bluefin tuna (ABFTE) stock has been considered as an archetype of overfishing and general mismanagement of national and international fisheries bodies. The crisis highlighted, among other things, the fact that uncertainties that are inherent to any scientific advice can be used in lobbying to attempt to discredit science-based management. It also showed how interactions between science and management can change through time according to public awareness and opinion. This long and highly publicized crisis finally came to an end, in 2009, when ICCAT, under the pressure of NGOs and public opinion, fully endorsed the scientific advice within a rebuilding plan. Nowadays, the ABFTE stock is recovering, even... |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00451/56277/57854.pdf |
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| Fromentin, Jean-marc. |
| The exploitation of Atlantic bluefin tuna in the Mediterranean Sea goes back to the first millennium before Christ and the Romans already took benefits of the bluefin tuna reproductive migration to catch them. Bluefin tuna catch did not remain stable along its millennium exploitation history but displayed conspicuous long-term fluctuations that could result from environmentally-driven changes in the bluefin tuna migration routes. The Nordic fisheries that took place in the Norwegian and North Sea in the early 1920s were the most spectacular example of Atlantic bluefin tuna fisheries collapse. During the 1950s, the Nordic fisheries were the most productive ones, catching up to 18,000 tons/year, but they suddenly crashed down without any warning in 1963.... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00193/30467/28872.pdf |
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| Van Beveren, Elisabeth; Fromentin, Jean-marc; Bonhommeau, Sylvain; Nieblas, Anne-elise; Metral, Luisa; Brisset, Blandine; Jusup, Marko; Bauer, Robert Klaus; Brosset, Pablo; Saraux, Claire. |
| Thunnus thynnus Sardina pilchardus Engraulis encrasicolus |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00371/48215/50340.pdf |
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| Kell, Laurence T.; Mosqueira, I; Grosjean, P; Fromentin, Jean-marc; Garcia, D; Hillary, R; Jardim, E; Mardle, S; Pastoors, M.a; Poos, J.j.; Scott, F; Scott, R. |
| The FLR framework (Fisheries Library for R) is a development effort directed towards the evaluation of fisheries management strategies. The overall goal is to develop a common framework to facilitate collaboration within and across disciplines (e.g. biological, ecological, statistical, mathematical, economic, and social) and, in particular, to ensure that new modelling methods and software are more easily validated and evaluated, as well as becoming widely available once developed. Specifically, the framework details how to implement and link a variety of fishery, biological, and economic software packages so that alternative management strategies and procedures can be evaluated for their robustness to uncertainty before implementation. The design of the... |
| Tipo: Text |
Palavras-chave: Uncertainty; Stock assessment; Software; Simulation framework; Precautionary approach; Open source; Management strategy evaluation; Bio economic modelling. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2732.pdf |
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| Registros recuperados: 129 | |
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