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| Registros recuperados: 37 | |
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| Imzilen, Taha; Bonhommeau, Sylvain; Rouyer, Tristan; Kell, Laurence T; Chassot, Emmanuel; Barde, Julien. |
| In this note, we present an approach which has been recently used to execute online the set of codes used for eastern blue_n tuna (BFT-E) stock assessment at ICCAT. We aim at discussing the possible interest of the approach to the IOTC Community for focusing on Indian ocean tuna and tuna-like stocks and running other assesment models such as Stock Synthesis 3 (SS3). In 2014, ICCAT BFT-E working group has been able to execute thousands of model runs by using parallelization of R and Fortran codes on a supercomputer. This approach has a lot of scienti_c bene_ts, in particular for better including the multiple sources of uncertainty in assessment results and associated scienti_c advice. However, very few participants would be able to reproduce it without... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00360/47135/47084.pdf |
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| Jadaud, Angelique; Rouyer, Tristan; Mellon, Capucine; Biseau, Alain; Morandeau, Fabien; Berthou, Patrick. |
| Rappel de la demande (saisine 14-7383) : - sur les données et la qualification de l’état des stocks de merlu et de rouget du golfe du Lion : · Une présentation critique des données scientifiques les plus récentes actuellement disponibles sur la mortalité par pêche et la biomasse du merlu et du rouget et de leur qualité · Une présentation critique des estimations de points de référence limite qui peuvent être faites pour les stocks de merlu et de rouget : biomasse limite (Blim) et biomasse minimum de précaution (Bpa), mortalité par pêche limite (Flim) et mortalité par pêche maximale de précaution (Fpa) et qui pourraient être reprises dans un plan de gestion. - sur les mesures de gestion complémentaires envisageables pour les pêcheries démersales du golfe du... |
| Tipo: Text |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00255/36590/35150.pdf |
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| David-grignot, Stephane; Lamlih, Achraf; Belhaj, Mohamed Moez; Kerzerho, Vincent; Azais, Florence; Soulier, Fabien; Freitas, Philippe; Rouyer, Tristan; Bonhommeau, Sylvain; Bernard, Serge. |
| In the context of biosensor as much as Built-In-Self Test (BIST), on-chip sine-wave signal generation is a recurring research topic. Considering the implementation constraints, it implies a trade-off between the amount of resources and the signal quality. An attractive solution consists in combining several digital signals to build this analog sine-wave. The objective of this paper is to give an analytic study of various potential digital-based solutions. Thanks to this study, we prove that the technique consisting in setting the phase shifts and various amplitude values of the square-wave signals is the most efficient approach. This study allows the selection of the optimal square-wave signal parameters to cancel low-order harmonics of the generated... |
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Palavras-chave: Harmonic cancelation; Sine-wave generation; On-chip signal generation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00425/53678/54609.pdf |
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| Casini, Michele; Rouyer, Tristan; Bartolino, Valerio; Larson, Niklas; Grygiel, Wlodzimierz. |
| Spatio-temporal density-dependent processes are crucial regulatory factors for natural populations. However, there is a lack of studies addressing spatial density-dependence in fish growth. A previous investigation has suggested spatio-temporal density-dependence in body condition of Baltic sprat. Here, we used different techniques, such as centre of gravity, distance, and homogeneity indices, to better characterize the spatial and temporal variations in sprat density and body condition in the Baltic Proper. Our results evidenced a negative spatio-temporal co-variation between the centres of gravity of density and maximum condition. In the 1980s-early 1990s both centres were located in the middle of the Baltic Proper. From the mid 1990s the centres... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00190/30091/28745.pdf |
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| Chassot, E; Rouyer, Tristan; Trenkel, Verena; Gascuel, D. |
| The trophic level mean and variance, and the degree of omnivory for five Celtic Sea fish predators were estimated using a database of stomach content records characterized by a high level of taxonomic resolution. The predators occupied a high position in the food web, i.e. 4.75 for Atlantic cod Gadus morhua, 444 for haddock Melanogrammus aeglefinus, 4.88 for European hake Merluccius merluccius, 5.00 for megrim Lepidorhombus whiffiagonis and 5.27 for whiting Merlangius merlangus. The level of taxonomic resolution of the prey did not greatly affect mean T-L predator values; an effect on variance was evident, low resolution masking intra-population variability in T-L. Generalized additive models (GAM) were used to explain the variability of predator T-L... |
| Tipo: Text |
Palavras-chave: Trophic level; Predation; Omnivory; Indicator; GAM; Food web. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4699.pdf |
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| Corbineau, A.; Rouyer, Tristan; Fromentin, Jean-marc; Cazelles, B.; Fonteneau, Alain; Menard, Frederic. |
| Catch data of large pelagic fish such as tuna, swordfish and billfish are highly variable ranging from short to long term. Based on fisheries data, these time series are noisy and reflect mixed information on exploitation (targeting, strategy, fishing power), population dynamics (recruitment, growth, mortality, migration, etc.), and environmental forcing (local conditions or dominant climate patterns). In this work, we investigated patterns of variation of large pelagic fish (i.e. yellowfin tuna, bigeye tuna, swordfish and blue marlin) in Japanese longliners catch data from 1960 to 2004. We performed wavelet analyses on the yearly time series of each fish species in each biogeographic province of the tropical Indian and Atlantic Oceans. In addition, we... |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00011/12231/9029.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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| Sardenne, Fany; Bodin, Nathalie; Metral, Luisa; Crottier, Anais; Le Grand, Fabienne; Bideau, Antoine; Brisset, Blandine; Bourjea, Jerome; Saraux, Claire; Bonhommeau, Sylvain; Kerzerho, Vincent; Bernard, Serge; Rouyer, Tristan. |
| Various protocols are currently used to study marine lipids, but there is a growing interest in working on dry samples that are easier to transport. However, reference protocols are still lacking for dry samples. In order to make recommendations on this use, lipid classes and fatty acids (FA) obtained from six analytical protocols using two different tissue states (dry vs wet) and three extraction methods (automat vs manual potter vs leaving the solvent to work on tissue) were compared. Three dry storage modes of tissue (freezer vs gas nitrogen vs dry room) during one and three months were also compared. These comparisons were made on seven marine species with different lipid profiles, including fishes, crustaceans and mollusks. Lipid classes and FA... |
| Tipo: Text |
Palavras-chave: Degradation; Freeze-drying; Lyophilization; Lipid class; Marine animal; Protocol. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00467/57898/60189.pdf |
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| Corbineau, A; Rouyer, Tristan; Cazelles, B; Fromentin, Jean-marc; Fonteneau, A; Menard, Felix. |
| We analysed the patterns of variation that characterize 33 catch time series of large pelagic fishes exploited by the Japanese and Taiwanese longline fisheries in the Indian Ocean from 1968 to 2003. We selected four species, the yellowfin (Thunnus albacares), the bigeye (T. obesus), the albacore (T. alalunga), and the swordfish (Xiphias gladius) and aggregated data into five biogeographic provinces of Longhurst (2001). We carried out wavelet analyses, an efficient method to study non-stationary time series, in order to get the time-scale patterns of each signals. We then compared and grouped the different wavelet spectra using a multivariate analysis to identify the factors (species, province or fleet) that may influence their clustering. We also... |
| Tipo: Text |
Palavras-chave: Indian Ocean; Dipole Mode Index; Longline fisheries; Wavelet analysis; Time series analysis; Pelagic fishes. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4714.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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| 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... |
| Tipo: Text |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00451/56277/57854.pdf |
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| Registros recuperados: 37 | |
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