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| Registros recuperados: 20 | |
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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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| Fromentin, Jean-marc. |
| This manuscript proposes a simple simulation model to investigate the implications to the resources of the recent management regulations adopted for the East Atlantic and Mediterranean bluefin tuna stock. If perfectly implemented, the new regulations on minimum size and closed fishing areas mostly lead to a change in the selectivity pattern which moves towards older fish, so decreasing growth-overfishing. The potential sustainable yields therefore considerably increase (almost double in comparison to those that would be obtained without the new regulations) while the SSB can rapidly reach 20% of the virgin SSB. An error of 20% in the implementation of these new regulations affects their efficiencies and does not seem to allow the rebuilding of the SSB at a... |
| Tipo: Text |
Palavras-chave: Bluefin tuna; Management regulations; Stock rebuilding; Simulation model. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/00192/30297/28787.pdf |
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| Aoki, Yoshinori; Jusup, Marko; Nieblas, Anne-elise; Bonhommeau, Sylvain; Kiyofuji, Hidetada; Kitagawa, Takashi. |
| Formal approaches to physiological energetics, such as the Dynamic Energy Budget (DEB) theory, enable interspecies comparisons by uniformly describing how individuals of different species acquire and utilise energy. We used the DEB theory to infer the energy budgets of three commercial tuna species (skipjack, Pacific bluefin, and Atlantic bluefin) throughout all stages of ontogenetic development—from an egg to an adult individual and its eggs. Energy budgets were inferred from exhaustive datasets fed into a DEB-based mathematical model tailored for tuna fish until reaching a high goodness of fit and thus reliable estimates of the model parameters. The life histories of all three species are strongly influenced by morphological and physiological adaptations... |
| Tipo: Text |
Palavras-chave: Accelerated ontogeny; Bluefin tuna; Dynamic Energy Budget theory; Ecology and evolution; Energy speculators; Skipjack tuna. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71238/69605.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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| Fromentin, Jean-marc; Bonhommeau, Sylvain. |
| This study aims at examining the selectivity patterns among gears and years of the fleets targeting bluefin tuna in the Northeast Atlantic and Mediterranean Sea between 1970 and 2009, using catch curve analyses. The main outputs may be summarized as follow: (i) the general pattern of selectivity has highly varied through time, moving from ages 1-3 to ages 10+ from the 1970s to the 2000s; (ii) this important temporal drift primarily resulted from changes in PS selectivity patterns; (iii) these drastic variations in selectivity among gears and years can affect simple indicators which do not incorporate such information; (iv) the catch-at-age (CAA) matrix seems to be impaired by several inconsistencies that affect primarily the partial CAA of the purse... |
| Tipo: Text |
Palavras-chave: Gear selectivity; Stock assessment; Bluefin tuna. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00192/30279/28747.pdf |
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| Fromentin, Jean-marc; Fonteneau, Alain. |
| This study aims to test whether exploitation affects tunas and tuna-like species displaying contrasting life history traits similarly. We first collected information on life history of 10 commercial Atlantic species and then compared this information using multivariate analysis. On one hand, tropical tunas are characterised by small to medium size, rapid growth, early age-at-maturity, long spawning duration and short life span. These species, therefore, display a rapid turnover, characteristic of r-selected species. On the other hand, temperate tunas display differing life history traits, i.e., large size, slow growth, late age-at-maturity, short spawning duration and long life span. The turnover of these species is slow and present characteristics similar... |
| Tipo: Text |
Palavras-chave: Management measures; Sustainability; Fishing; Long term fluctuations; Simulation modelling; Skipjack; Bluefin tuna. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-434.pdf |
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| Labelle, Marc; Hoch, Thierry; Liorzou, Bernard; Bigot, Jean-louis. |
| Sampling operations are not routinely conducted in France to monitor the landings of bluefin tuna caught by purse seiners in the Mediterranean. The length, weight and age frequencies of bluefin caught by this fleet are predicted based on sale records, length-at-age and weight-length relations, trends in fishing and natural mortality rates, and other ancillary data. The resulting length frequencies are more accurate than those predicted by Liorzou and Bigot (1992) using a simpler algorithm, and are spread more evenly across adjacent size classes. Catch-per-unil-effort (CPUE) was expressed as the numbers of age 2 bluefin caught per successful seine fishing trip in the Gulf of Lions fall fishery. CPUE indices were computed by several methods, and compared to... |
| Tipo: Text |
Palavras-chave: Thon rouge; Senne tournante; Prises-par-unité-d'effort; Indices d'abondance; Taux de croissance; Évaluation des stocks; Mer Méditerranée; Bluefin tuna; Purse seine; Catch-per-unit-effort; Abundance indices; Growth rates; Stock-assessment; Mediterranean sea. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00188/29880/28357.pdf |
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| Farrugia, A.F.; Pla, C.; Viñas, J.; Tawil, M.Y.; Hattour, A.; de la Serna, J.M.. |
| None of the previous genetic analysis found significant differences within the Mediterranean. However, a more exhaustive analysis is needed inside this sea. In this sense, we have analyzed the mitochondrial control region sequence variability of three Mediterranean locations: Libya (n = 22), Tunisia (n = 23) and Malta (n = 12). Additionally a sample from the Gulf of Cadiz (n = 24) in the East Atlantic Ocean was also included in the study. The AMOVA analysis revealed slightly (Fst = 0.013) but significative genetic differences (P < 0.000) for the Malta location, probably due to its small sample size (n = 12). In the other hand, when this location is removed from the analysis, no differences where found among the three remaining location (Fst = 0,005; P =... |
| Tipo: Journal Contribution |
Palavras-chave: Atlantic ocean; Mitochondrial DNA; Bluefin tuna; Sequencing; Genetic characterization; Mediterranean sea; Tuna fisheries. |
| Ano: 2003 |
URL: http://hdl.handle.net/1834/792 |
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| Duclerc, J; Sacchi, J; Piccinetti, C; Piccinetti-manfrin, G; Dicenta, A; Barrois, J-m. |
| Two international research cruises on board of the research vessel 'Ichthys' the first one in Aug-Sept 1971, and the second other in June-July 1972, have shown the reproduction of Thunnus thynnus, T.alalunga, Auxis thazard and Sarda in the surroundings of the Balearic Islands. The observations were made on the planctonic stages of these spp and on the physico-chemical and biological conditions of the environment. Some data were also collected on the presence of juvenile or mature stages of these fishes and on their fishery. |
| Tipo: Text |
Palavras-chave: Plankton; Eggs; Larvae; Physico chemical conditions; Mediterranean sea; Reproduction; Thunnidae; Bluefin tuna. |
| Ano: 1973 |
URL: http://archimer.ifremer.fr/doc/1973/publication-2159.pdf |
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| Kimoto, A; Walter, Jf; Sharma, R; Rouyer, Tristan. |
| ICCAT BFTWG completed the stock assessment using multiple stock assessment methods in 2017, and they are going to proceed with the MSE process: development of MP in 2018. It is well recognized that the performance results of MPs often depend on the design of the OM and its conditioning that capture the range of potential population dynamics. It is therefore critical to consider them carefully before moving to the development of MP, but this has been a monumental task given the complexity of ABFT. The ICCAT GBYP Core modelling group has developed the OM by incorporating the mixing between two stocks, and the trial specifications. However, the 2017 stock assessment raised a number of issues that may require further consideration for the OMs, particularly... |
| Tipo: Text |
Palavras-chave: Bluefin tuna; Conditioning; Operating model; Uncertainty; Management procedure; MSE. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00484/59607/62624.pdf |
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| Bonhommeau, Sylvain; Fromentin, Jean-marc. |
| This study aims at examining the potential bias in the VPA estimates by simulating a population, catch and CPUEs over 39 years from 1970 to 2008. In the operational model, two levels of noise were added to catch and CPUEs (50 and 100%), three fishing patterns were explored (F=FMSY, F increases linearly from 0.5 FMSY to 2.5 FMSY, F increases linearly from 0.5 FMSY to 2.5 FMSY over the first 34 years and decreases down to FMSY over the last 5 years). We also tested different hypothesis about the impact of the terminal F-ratios, and the natural mortality used in the current VPA as well as the impact of randomly generated CPUE for long-line and trap CPUE. Results show that the VPA is robust to estimate the SSB whatever the noise level in the catch and the... |
| Tipo: Text |
Palavras-chave: Bluefin tuna; Stock assessment; VPA; Management regulations; TAC. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00192/30280/28755.pdf |
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| Registros recuperados: 20 | |
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