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| Registros recuperados: 129 | |
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| Fromentin, Jean-marc; Ibanez, F. |
| Chronological series (1949 to 1992) of air temperature, precipitation, atmospheric pressure and wind in different parts of the French coast show evidence of important year-to-year changes, trends and cycles: seven-eight years for temperature, and around three years for precipitation and atmospheric pressure. On the scale of France, it appears that spatial heterogeneity of meteorological factors is smaller than temporal heterogeneity. New methods, such as the cumulative sums method or the envelopes of a variable reveal the interest for ecologists of essaying different numerical approaches. A comparison between climatic series and biological series of a benthic and a pelagic species is described for this purpose. |
| Tipo: Text |
Palavras-chave: METEOROLOGICAL SERIES; BIOLOGICAL SERIES; TRENDS; CYCLES; CHANGES. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00098/20891/18505.pdf |
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| Kell, Laurence T; Fromentin, Jean-marc. |
| Reference points are important elements of fisheries management and the supporting scientific advisory frameworks. However, fish stocks can fluctuate extensively over a large range of spatial and temporal scales independent of human exploitation and there has been a classical tendency to assume a dichotomy, i.e., that changes in fish populations are primarily attributable either to exploitation or to environmental variability. Therefore we look at variability in surplus production and examine the relative impacts of the environment and exploitation on the productivity of North Atlantic albacore (Thunnus alalunga). The analysis revealed that variations were driven by environmental effects. It was also found that substantial variations in time-series of... |
| Tipo: Text |
Palavras-chave: Thunnus alalunga; Albacore; Fisheries management; FLR; Reference points; Stationary processes; Surplus production.. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00192/30282/28758.pdf |
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| Pons, Maite; Branch, Trevor A.; Melnychuk, Michael C.; Jensen, Olaf P.; Brodziak, Jon; Fromentin, Jean-marc; Harley, Shelton J.; Haynie, Alan C.; Kell, Laurie T.; Maunder, Mark N.; Parma, Ana M.; Restrepo, Victor R.; Sharma, Rishi; Ahrens, Robert; Hilborn, Ray. |
| Commercial tunas and billfishes (swordfish, marlins and sailfish) provide considerable catches and income in both developed and developing countries. These stocks vary in status from lightly exploited to rebuilding to severely depleted. Previous studies suggested that this variability could result from differences in life-history characteristics and economic incentives, but differences in exploitation histories and management measures also have a strong effect on current stock status. Although the status (biomass and fishing mortality rate) of major tuna and billfish stocks is well documented, the effect of these diverse factors on current stock status and the effect of management measures in rebuilding stocks have not been analysed at the global level.... |
| Tipo: Text |
Palavras-chave: Fisheries management; Marine conservation; Stock assessment; Stock status; Tuna fisheries. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00333/44383/44107.pdf |
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| Fromentin, Jean-marc; Arrizabalaga, Haritz; Restrepo, Victor R; Ortiz De Urbina, J. |
| The 2004 data exploratory meeting concluded that it was no longer defensible to assess the East Atlantic and Mediterranean population using methods that assume that the catch-atsize/age is known exactly, until extensive improvements in fisheries statistics are made. For these reasons, we here investigated the potential benefits of the year-class curve analysis. The robustness and consistency of our results tend to advocate that this method is, in the present situation, a good alternative to ADAPT (among others). As a whole, the estimates of Z from the year-class curve analyses applied on the Spanish trap and Japanese long line fishery data appear indeed to be in good or excellent agreement with ADAPT outputs for the same period and same age-classes. This... |
| Tipo: Text |
Palavras-chave: Fishing and natural mortalities; Year-class curves; Stock assessment. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00192/30325/28799.pdf |
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| Mellon, Capucine; Harmelin-vivien, Mireille; Metral, Luisa; Loizeau, Veronique; Mortreux, Serge; Roos, David; Fromentin, Jean-marc. |
| The European hake, Merluccius merluccius, is an important resource for Mediterranean fisheries. This study focuses on juvenile and adult hake feeding ecology in the Gulf of Lions, using information from scientific surveys carried out during two seasons and three years (2004-2006). Stomach content and stable isotope (ä15N, ä13C) analyses were performed, and the main factors explaining variations in ä15N were investigated using GLMs. In the Gulf of Lions, hake mostly fed on crustaceans and fish and a dominant piscivorous regime was reached at 15 cm total length. Pelagic fish (sardine, anchovy and small blue whiting) were the main source of prey (40%-80%) and cannibalism was low (<5%). The results confirmed that hake is an opportunistic feeder and also... |
| Tipo: Text |
Palavras-chave: Foodweb; GLM; Habitat; Merluccius merluccius; Predator-prey relationships; Stable isotopes; Stomach contents. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00360/47091/47016.pdf |
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| Fromentin, Jean-marc; Fonteneau, Alain; Farrugio, Henri. |
| Defining biological key reference points is of importance within the precautionary approach. Most of the reference points, such as the FMSY, Fo.], presuppose a steady state, i.e. the natural long-term fluctuations of the population are low or moderate. In this manuscript, we present historical data from Sicilian, Sardinian, Portuguese, and Tunisian traps of the Atlantic bluefin tuna during 200 to 400 years. Long-term fluctuations in trap data could be considered as a good proxy for long-term trend in true abundance because trap is a passive gear which was submitted to low modification until the XX century and because data from different areas display similar long-term variations. Trends in trap data appear beIl shaped, with a maximum at the end ofthe XIXth... |
| Tipo: Text |
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| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00194/30485/28890.pdf |
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| Restrepo, Victor R; Ortiz De Urbina, J; Fromentin, Jean-marc; Arrizabalaga, Haritz. |
| Knowledge of gear-specific selectivity patterns can be useful in age-structured analyses. In recent assessments of eastern Atlantic bluefin tuna, Thunnus thynnus, the SCRS has derived selectivity estimates from the results of virtual population analyses. This document proposes an alternative approach, based on equilibrium catch curves, that is simple to apply and that relies on a smaller set of assumptions. The study uses the catch-at-age data from the last assessment conducted in 2002, and estimates recent and historical selectivity patterns for the total stock as well as some of the major gears (trap, baitboat, purse seine and longline). The resulting estimates seem reasonable for the various gears, given prior knowledge. The document also presents... |
| Tipo: Text |
Palavras-chave: Gear selectivity; Stock assessment; Bluefin tuna. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00192/30326/28800.pdf |
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| Arrizabalaga, Haritz; Dufour, Florence; Kell, Laurence; Merino, Gorka; Ibaibarriaga, Leire; Chust, Guillem; Irigoien, Xabier; Santiago, Jose Luis; Murua, Hilario; Fraile, Igaratza; Chifflet, Marina; Goikoetxea, Nerea; Sagarminaga, Yolanda; Aumont, Olivier; Bopp, Laurent; Herrera, Miguel; Fromentin, Jean-marc; Bonhomeau, Sylvain. |
| In spite of its pivotal role in future implementations of the Ecosystem Approach to Fisheries Management, current knowledge about tuna habitat preferences remains fragmented and heterogeneous, because it relies mainly on regional or local studies that have used a variety of approaches making them difficult to combine. Therefore in this study we analyse data from six tuna species in the Pacific, Atlantic and Indian Oceans in order to provide a global, comparative perspective of habitat preferences. These data are longline catch per unit effort from 1958 to2007 for albacore, Atlantic bluefin, southern bluefin, bigeye, yellowfin and skipjack tunas. Both quotient analysis and Generalized Additive Models were used to determine habitat preference with respect to... |
| Tipo: Text |
Palavras-chave: Habitat; Tuna fisheries; Catch/effort; Environmental conditions; Quotient analysis; Generalised Additive Models; Ecosystem Approach to Fisheries Management. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00201/31190/29589.pdf |
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| Royer, Francois; Fromentin, Jean-marc; Gaspar, P. |
| Archival tagging provides a unique way to study the spatial dynamics and habitat of pelagic fish. This technique generates lagrangian data of a particular type in marine ecology: although highly informative about processes at different scales (e.g. horizontal movements versus diving behaviour), such data are impaired by location errors and the lack of combination with actual environmental variability. The present paper introduces a framework for modelling bluefin tuna movement in relation to its habitat, using records of light, depth and temperature from archival tags. Based on data assimilation concepts and methods, we show how an explicit formulation of the observation process and the statistics of external variables (e.g. ambient temperature) can... |
| Tipo: Text |
Palavras-chave: Tag; Archival; Habitat; Movement; Bluefin tuna. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-671.pdf |
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| Granger, Victoria; Fromentin, Jean-marc; Bez, Nicolas; Relini, Giulio; Meynard, Christine N.; Gaertner, Jean-claude; Maiorano, Porzia; Garcia Ruiz, Cristina; Follesa, Cristina; Gristina, Michele; Peristeraki, Panagiota; Brind'Amour, Anik; Carbonara, Pierluigi; Charilaou, Charis; Esteban, Antonio; Jadaud, Angelique; Joksimovic, Aleksandar; Kallianiotis, Argyris; Kolitari, Jerina; Manfredi, Chiara; Massuti, Enric; Mifsud, Roberta; Quetglas, Antoni; Refes, Wahid; Sbrana, Mario; Vrgoc, Nedo; Spedicato, Maria Teresa; Merigot, Bastien. |
| Increasing human pressures and global environmental change may severely affect the diversity of species assemblages and associated ecosystem services. Despite the recent interest in phylogenetic and functional diversity, our knowledge on large spatio-temporal patterns of demersal fish diversity sampled by trawling remains still incomplete, notably in the Mediterranean Sea, one of the most threatened marine regions of the world. We investigated large spatio-temporal diversity patterns by analysing a dataset of 19,886 hauls from 10 to 800 m depth performed annually during the last two decades by standardized scientific bottom trawl field surveys across the Mediterranean Sea, within the MEDITS program. A multi-component (eight diversity indices) and... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00216/32743/31322.pdf |
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| Fromentin, Jean-marc. |
| Since 2007, Ifremer together with the French Federation of Sport fishermen (FFPM) and Big Game Fishing Club France (BGFCF) have been carrying out a program of conventional and electronic tagging on bluefin tuna in the western Mediterranean Sea. 479 and 95 ICCAT “spaghetti” tags have been deployed by the FFPM recreational and sportive fishermen along the Mediterranean French coasts in 2007 and 2008, respectively. To date, not a single recapture has been registered. Ifremer together with BGFCF has deployed 11, 6 and 8 pop-up archival tags (PAT) offshore of Marseille in 2007, 2008 and 2009, respectively. Outputs were impaired by two main technical difficulties: premature detachment and low transmission rates in the Argos band over the Mediterranean. While... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Tagging; Mediterranean Sea; Pop-up archival tag; Conventional tag. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00192/30291/28770.pdf |
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| Registros recuperados: 129 | |
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