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| Registros recuperados: 129 | |
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| Brosset, Pablo; Fromentin, Jean-marc; Van Beveren, Elisabeth; Lloret, Josep; Marques, Virginie; Basilone, Gualtiero; Bonanno, Angelo; Carpi, Piera; Donato, Fortunata; Kec, Vanja Cikes; De Felice, Andrea; Ferreri, Rosalia; Gasparevic, Denis; Giraldez, Ana; Gucu, Ali; Iglesias, Magdalena; Leonori, Iole; Palomera, Isabel; Somarakis, Stylianos; Ticina, Vjekoslav; Torres, Pedro; Ventero, Ana; Zorica, Barbara; Menard, Frederic; Saraux, Claire. |
| Small pelagic fish are among the most ecologically and economically important marine fish species and are characterized by large fluctuations all over the world. In the Mediterranean Sea, low catches and biomass of anchovies and sardines have been described in some areas during the last decade, resulting in important fisheries crises. Therefore, we studied anchovy and sardine body condition variability, a key index of population health and its response to environmental and anthropogenic changes. Wide temporal and spatial patterns were investigated by analyzing separately data from scientific surveys and fisheries in eight Mediterranean areas between 1975 and 2015. Results showed that anchovy and sardine body condition as well as maximum size in some areas... |
| Tipo: Text |
Palavras-chave: Anchovy; Sardine; Fish health; Marine monitoring. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00363/47400/47936.pdf |
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| Brosset, Pablo; Menard, Frederic; Fromentin, Jean-marc; Bonhommeau, Sylvain; Ulses, Caroline; Bourdeix, Jean-herve; Bigot, Jean-louis; Van Beveren, Elisabeth; Roos, David; Saraux, Claire. |
| Endogenous and environmental variables are fundamental in explaining variations in fish condition. Based on more than 20 yr of fish weight and length data, relative condition indices were computed for anchovy and sardine caught in the Gulf of Lions. Classification and regression trees (CART) were used to identify endogenous factors affecting fish condition, and to group years of similar condition. Both species showed a similar annual cycle with condition being minimal in February and maximal in July. CART identified 3 groups of years where the fish populations generally showed poor, average and good condition and within which condition differed between age classes but not according to sex. In particular, during the period of poor condition (mostly recent... |
| Tipo: Text |
Palavras-chave: Anchovy; Sardine; Relative condition factor; NW Mediterranean Sea; Endogenous effect; Environmental effect. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00272/38334/36575.pdf |
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| Kell, L. T.; Fromentin, Jean-marc. |
| This paper presents an example of Management Strategy Evaluation (MSE) for Mediterranean and East Atlantic bluefin tuna using the FLR open source framework. Scenarios corresponding to alternative plausible hypotheses about the stock dynamics were used to evaluate alternative management strategies and to test their robustness to implementation error e.g. catch mis-reporting. The strategies evaluated correspond to i) harvest control rule (HCR) based upon F0.1 (a proxy for FMSY ) with an objective of restoring the stock to a level that would “ permit the maximum sustainable catch” and ii) a reduction of fishing mortality on immature fish. The main conclusions were that the F0.1 HCR alone would not result in the recovery of the stock in the next 15 years and... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Management plans; Management strategy evaluation; Simulation model. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00194/30477/28884.pdf |
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| Fromentin, Jean-marc; Restrepo, Victor. |
| Variations in recruitment and year-class strength of fish populations is a well known feature which can be related to three main factors: 1) human activity, mainly through overexploitation of the spawning stock, but also through pollution of the spawning and nursery areas; 2) biological processes, such as predation, cannibalism and competition and 3) environmental events. Life history traits of Atlantic tuna make the probability of a stable recruitment much higher for tropical tuna than temperate ones, but the latter are more adapted to the risks of recruitment failures than the former. As noise in the recruitment can lead to pseudo-cyclic variations in SSB and yields, trends in stock size and catches are also more likely in temperate Atlantic tuna. All... |
| Tipo: Text |
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| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00194/30562/28983.pdf |
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| Biseau, Alain; Bellail, Robert; Bertignac, Michel; Biais, Gerard; Bigot, Jean-louis; Bouche, Ludovic; Bourjea, Jerome; Caro, Anthony; De Casamajor, Marie-noelle; Caill-milly, Nathalie; Drogou, Mickael; Duhamel, Erwan; Fifas, Spyros; Foucher, Eric; Fromentin, Jean-marc; Jadaud, Angelique; Lampert, Luis; Laurans, Martial; Lissardy, Muriel; Lorance, Pascal; Mahe, Jean-claude; Mahe, Kelig; Masse, Jacques; Morandeau, Gilles; Pawlowski, Lionel; Poisson, Francois; Reynal, Lionel; Roos, David; Verin, Yves; Vermard, Youen; Vigneau, Joel. |
| Ce document présente l'état des principaux stocks exploités par les flottes françaises en termes de mortalité par pêche et de biomasse de reproducteurs. La situation fin 2010 (début 2011) par rapport aux points de référence (de précaution et Fmsy) est indiqué lorsque les indicateurs sont estimés et que les références sont définies. Les grandes tendances en matière d'évolution des mortalités et biomasses sont également indiquées. |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00035/14656/11956.pdf |
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| Planque, Benjamin; Fromentin, Jean-marc; Cury, Philippe; Drinkwater, Kenneth F.; Jennings, Simon; Perry, R. Ian; Kifani, Souad. |
| Evidence has accumulated that climate variability influences the state and functioning of marine ecosystems. At the same time increasing pressure from exploitation and other human activities has been shown to impact exploited and non-exploited species and potentially modify ecosystem structure. There has been a tendency among marine scientists to pose the question as a dichotomy, i.e., whether (1) "natural" climate variability or (2) fishery exploitation bears the primary responsibility for population declines in fish populations and the associated ecosystem changes. However, effects of both climate and exploitation are probably substantially involved in most cases. More importantly, climate and exploitation interact in their effects, such that climate may... |
| Tipo: Text |
Palavras-chave: Resilience; Marine ecosystems; Demography; Climate fishing interactions. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/2010/publication-7384.pdf |
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| Queiros, Quentin; Fromentin, Jean-marc; Gasset, Eric; Dutto, Gilbert; Huiban, Camille; Metral, Luisa; Leclerc, Lina; Schull, Quentin; Mckenzie, David; Saraux, Claire. |
| Small pelagic fish are key components of marine ecosystems and fisheries worldwide. Despite the absence of recruitment failure and overfishing, pelagic fisheries have been in crisis for a decade in the Western Mediterranean Sea because of a marked decline in sardine size and condition. This situation most probably results from bottom-up control and changes in the plankton community toward smaller plankton. To understand such an unusual phenomenon, we developed an original and innovative experimental approach investigating the mechanisms induced by a reduction in the quantity and size of sardine prey. While experimentations offer the unique opportunity to integrate behavior and ecophysiology in understanding key demographic processes, they remain rarely... |
| Tipo: Text |
Palavras-chave: Experimentation; Small pelagics; Sardina pilchardus; Body condition; Bottom-up control. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00505/61669/65585.pdf |
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| Planque, Benjamin; Mullon, Christian; Arneberg, Per; Eide, Arne; Fromentin, Jean-marc; Heymans, Johanna Jacomina; Hoel, Alf Håkon; Niiranen, Susa; Ottersen, Geir; Sandø, Anne Britt; Sommerkorn, Martin; Thébaud, Olivier; Thorvik, Thorbjørn. |
| Anticipating future changes in marine social‐ecological systems (MSES) several decades into the future is essential in the context of accelerating global change. This is challenging in situations where actors do not share common understandings, practices, or visions about the future. We introduce a dedicated scenario method for the development of MSES scenarios in a participatory context. The objective is to allow different actors to jointly develop scenarios which contain their multiple visions of the future. The method starts from four perspectives: “fisheries management,” “ecosystem,” “ocean climate,” and “global context and governance” for which current status and recent trends are summarized. Contrasted scenarios about possible futures are elaborated... |
| Tipo: Text |
Palavras-chave: Barents Sea; Future studies; Multiple perspectives; Participatory fisheries management; Storylines; Uncertainty. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00485/59621/62647.pdf |
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| Saraux, Claire; Fromentin, Jean-marc; Bigot, Jean-louis; Bourdeix, Jean-herve; Morfin, Marie; Roos, David; Van Beveren, Elisabeth; Bez, Nicolas. |
| Understanding the ecological and anthropogenic drivers of population dynamics requires detailed studies on habitat selection and spatial distribution. Although small pelagic fish aggregate in large shoals and usually exhibit important spatial structure, their dynamics in time and space remain unpredictable and challenging. In the Gulf of Lions (north-western Mediterranean), sardine and anchovy biomasses have declined over the past 5 years causing an important fishery crisis while sprat abundance rose. Applying geostatistical tools on scientific acoustic surveys conducted in the Gulf of Lions, we investigated anchovy, sardine and sprat spatial distributions and structures over 10 years. Our results show that sardines and sprats were more coastal than... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00226/33739/32151.pdf |
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| Dauvin, Jean-claude; Dewarumez, Jean-marie; Elkaim, B; Bernardo, D; Fromentin, Jean-marc; Ibanez, F. |
| Populations of Abra alba (Wood) (Mollusca : Bivalvia) were studied over a fifteen-years period at three sites: the southern part of the North Sea (Gravelines area), the Bay of Seine, and the Bay of Morlaix in the western English Channel. These surveys provide an example of long-term changes in a species considered as ''opportunistic'' and as a ''biological indicator'' of disturbance. A summed cumulated function was used to compare the changes of the Abra alba populations and of mean air temperature in each area. The graph of this function shows the timing and duration of changes. Four or five main periods were identified at each site, with a succession of periods of abundance, stability, and decrease. The abundance periods were separated by ten years in... |
| Tipo: Text |
Palavras-chave: ABRA-ALBA; LONG-TERM CHANGES; CYCLES; CLIMATIC STRESS. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00099/21066/18692.pdf |
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| Restrepo, Victor; Arrizabalaga, Haritz; Ortiz De Urbina, J M; Fromentin, Jean-marc. |
| A standard yield per recruit (YPR) analysis is used to analyse the effects of minimum size regulations on bluefin tuna from the Eastern stock (East Atlantic and Mediterranean). Analyses were based on a selectivity vector computed over the period 1990- 1994 for which data were more reliable and VPA (performed during the 2002 stock assessment) showed a relatively good convergence. This selectivity vector was modified according to different minimum size regulations and implementation error levels. It is concluded that: (i) perfect implementation of the size limit regulation adopted in 2004 would increase YPR by 4.3% relative to the size limit adopted in 2002, and by 8.8% relative to the pattern realized in the early 1990s; (ii) YPR is however expected to... |
| Tipo: Text |
Palavras-chave: Yield/recruit; Yield predictions; Size limit regulations; Bluefin tuna.. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00194/30545/28964.pdf |
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| Pusineri, Claire; Ravier, Christelle; Fromentin, Jean-marc. |
| A retrospective analysis (1951-1979) was carried out on the bluefin tuna Nordic fisheries (Norway and Germany) length and weight data distributions and compared to those of Barbate trap (Gibraltar strait, Spain) to test further Tiews’ hypothesis about the disappearance of bluefin tuna in northern seas. The cohorts were identified from weight/length distributions and compared using multivariate analyses. The results showed: (i) a synchronous ageing in the 4 fisheries, (ii) similar dominant cohorts between South Norway and Barbate in the one hand (cohorts born from 1948 to 1952) and North Norway and Germany on the other hand (cohort born in 1945), (iii) a synchronous drop (or collapse) in the catches that occurred in 1963and (iv) significant correlation... |
| Tipo: Text |
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| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00194/30500/28910.pdf |
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| Fromentin, Jean-marc; Bonhommeau, Sylvain; Kell, Laurence; Restrepo, Victor. |
| Estimating the productivity of an exploited marine species is not an easy or a trivial task. In the case of Atlantic bluefin tuna, the productivity can hardly be estimated from the natural mortality rates or the stock recruitment relationships because the former have never been estimated for this species from scientific data, but only “guesstimated”, while the latter remain highly uncertain for both the eastern stock (BFTE) and the western stock (BFTW). To get a better idea of bluefin tuna productivity, we thus applied the approach by Jennings et al. (1998) who proposed a surrogate of r, r’, named the potential rate of population increase. We compared this parameter and age-at-maturity (and to some extent the individual growth curves) of 25 species... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Population growth rate; Fecundity; Maturity; CITES criteria. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00192/30293/28777.pdf |
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| Saraux, Claire; Van Beveren, Elisabeth; Brosset, Pablo; Queiros, Quentin; Bourdeix, Jean-herve; Dutto, Gilbert; Gasset, Eric; Jac, Cyrielle; Bonhommeau, Sylvain; Fromentin, Jean-marc. |
| Around 2008, an ecosystem shift occurred in the Gulf of Lions, highlighted by considerable changes in biomass and fish mean weight of its two main small pelagic fish stocks (European anchovy, Engraulis encrasicolus; European sardine, Sardina pilchardus). Surprisingly these changes did not appear to be mediated by a decrease in fish recruitment rates (which remained high) or by a high fishing pressure (exploitation rates being extremely low). Here, we review the current knowledge on the population's dynamics and its potential causes. We used an integrative ecosystem approach exploring alternative hypotheses, ranging from bottom-up to top-down control, not forgetting epizootic diseases. First, the study of multiple population characteristics highlighted a... |
| Tipo: Text |
Palavras-chave: Population dynamics; Top-down; Disease; Zooplankton; Exploited species; Bottom-up. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00427/53861/54903.pdf |
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| Registros recuperados: 129 | |
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