|
|
|
| Registros recuperados: 63 | |
|
| |
|
| |
|
|
| Bauer, Robert; Bonhommeau, Sylvain; Brisset, Blandine; Fromentin, Jean-marc. |
| Conservation and management measures for exploited fish species rely on our ability to monitor variations in population abundance. In the case of the eastern stock of Atlantic bluefin tuna (ABFT), recent changes in management policies have strongly affected the reliability of fishery-dependent indicators due to drastic changes in fishing season/area, fisheries selectivity and strategy. However, fishery-independent indices of abundance are rare for large pelagic fish, and obtaining them is often costly and labor intensive. Here, we show that scientific aerial surveys are an appropriate tool for monitoring juvenile bluefin tuna abundance in the Mediterranean. We present an abundance index based on 62 aerial surveys conducted since 2000, using 2 statistical... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Index of abundance; Fishery-independent; Gulf of Lions; Mediterranean Sea; Strip transect; Distance sampling. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00281/39192/45096.pdf |
| |
|
| |
|
| |
|
|
| David-grignot, Stephane; Lamlih, Achraf; Kerzerho, Vincent; Azaıs, Florence; Soulier, Fabien; Bernard, Serge; Rouyer, Tristan; Bonhommeau, Sylvain. |
| On-chip sine-wave signal generation is widely covered by literature for Built-In-Self Test (BIST) or biosensor applications. The objective is to generate pure and robust sinewave signal with minimal hardware resources. An attractive solution consists in combining several digital signals to built this analog sine-wave. The objective of this paper is to give an analytical study of various potential solutions based on digitalbased approaches. Thanks to this study, we prove that technique consisting in setting the phase shifts and various amplitude values of the square-wave signals is the most efficient approach. Moreover, this study allows the selection of the best solution in terms of parameters of the square-wave signals to cancel loworder harmonics of the... |
| Tipo: Text |
Palavras-chave: Harmonic cancellation; Sine-wave generation; On-chip signal generation. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00395/50608/55366.pdf |
| |
|
|
| 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 |
| |
|
|
| Rouyer, Tristan; Bonhommeau, Sylvain; Giordano, F; Wendling, B; Ellul, S; Ellul, G; Psaila, Ma; Deguara, S; Bernard, S; Kerzerho, V. |
| Tipo: Text |
Palavras-chave: Large atlantic bluefin tuna; Mediterranean; Malta; Electronic tagging; Farming cages; Purse seiners. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00484/59609/62626.pdf |
| |
|
| |
|
|
| Barde, J.; Bonhommeau, Sylvain; Chassot, E.; Motah, B.. |
| ollecting data on aquatic biodiversity is very challenging because of the difficulty to access underwater ecosystems. Over the years, field surveys have become easier and cheaper with the development of low cost electronics. Commercial and recreational vessels, including sailboats, can now substantially complement expensive scientific surveys and arrays of observation buoys deployed across the world oceans (Pesant et al., 2015, Karsenti et al., 2011). Meanwhile, a large variety of marine animals such as birds, mammals, and fish have become data collection platforms for both biological and environmental parameters through the advent of archival tags. It becomes obvious that data collection in coastal and high seas will become more popular and that citizen... |
| Tipo: Text |
Palavras-chave: Citizen science; Ocean and coastal observing systems; Surfing; Action cameras; Coral reef mapping; Photogrammetry; Deep learning; R. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00450/56164/57712.pdf |
| |
|
|
| Nikolic, Natacha; Montes, Iratxe; Lalire, Maxime; Puech, Alexis; Bodin, Nathalie; Arnaud-haond, Sophie; Kerwath, Sven; Corse, Emmanuel; Gaspar, Philippe; Hollanda, Stéphanie; Bourjea, Jerome; West, Wendy; Bonhommeau, Sylvain. |
| Albacore tuna (Thunnus alalunga) is an important target of tuna fisheries in the Atlantic and Indian Oceans. The commercial catch of albacore is the highest globally among all temperate tuna species, contributing around 6% in weight to global tuna catches over the last decade. The accurate assessment and management of this heavily exploited resource requires a robust understanding of the species’ biology and of the pattern of connectivity among oceanic regions, yet Indian Ocean albacore population dynamics remain poorly understood and its level of connectivity with the Atlantic Ocean population is uncertain. We analysed morphometrics and genetics of albacore (n = 1,874) in the southwest Indian (SWIO) and southeast Atlantic (SEAO) Oceans to investigate the... |
| Tipo: Text |
|
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00653/76483/77555.pdf |
| |
|
|
| 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 |
|
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00284/39481/37969.pdf |
| |
|
|
| Nieblas, Anne-elise; Drushka, Kyla; Reygondeau, Gabriel; Rossi, Vincent; Demarcq, Herve; Dubroca, Laurent; Bonhommeau, Sylvain. |
| The Mediterranean and Black Seas are semi-enclosed basins characterized by high environmental variability and growing anthropogenic pressure. This has led to an increasing need for a bioregionalization of the oceanic environment at local and regional scales that can be used for managerial applications as a geographical reference. We aim to identify biogeochemical subprovinces within this domain, and develop synthetic indices of the key oceanographic dynamics of each subprovince to quantify baselines from which to assess variability and change. To do this, we compile a data set of 101 months (2002-2010) of a variety of both "classical'' (i.e., sea surface temperature, surface chlorophyll-a, and bathymetry) and "mesoscale'' (i.e., eddy kinetic energy,... |
| Tipo: Text |
|
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00239/34995/33536.pdf |
| |
|
|
| 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 |
| |
|
|
| Bonhommeau, Sylvain; Dubroca, Laurent; Le Pape, Olivier; Barde, Julien; Kaplan, David; Chassot, Emmanuel; Nieblas, Anne-elise. |
| Trophic levels are critical for synthesizing species' diets, depicting energy pathways, understanding food web dynamics and ecosystem functioning, and monitoring ecosystem health. Specifically, trophic levels describe the position of species in a food web, from primary producers to apex predators (range, 1-5). Small differences in trophic level can reflect large differences in diet. Although trophic levels are among the most basic information collected for animals in ecosystems, a human trophic level (HTL) has never been defined. Here, we find a global HTL of 2.21, i.e., the trophic level of anchoveta. This value has increased with time, consistent with the global trend toward diets higher in meat. National HTLs ranging between 2.04 and 2.57 reflect a... |
| Tipo: Text |
Palavras-chave: Human ecology; Nutrition transition; Trophic ecology. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00171/28190/26609.pdf |
| |
|
|
| 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 |
| |
|
|
| Simon, Maximilien; Fromentin, Jean-marc; Bonhommeau, Sylvain; Gaertner, Daniel; Brodziak, Jon; Etienne, Marie-pierre. |
| The intrinsic population growth rate (r) of the surplus production function used in the biomass dynamic model and the steepness (h) of the stock-recruitment relationship used in age-structured population dynamics models are two key parameters in fish stock assessment. There is generally insufficient information in the data to estimate these parameters that thus have to be constrained. We developed methods to directly estimate the probability distributions of r and h for the Atlantic bluefin tuna (Thunnus thynnus, Scombridae), using all available biological and ecological information. We examined the existing literature to define appropriate probability distributions of key life history parameters associated with intrinsic growth rate and steepness, paying... |
| Tipo: Text |
|
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00115/22640/20362.pdf |
| |
|
|
| 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 |
| |
|
|
| Bonhommeau, Sylvain; Le Pape, O.; Gascuel, D.; Blanke, Bruno; Treguier, Anne-marie; Grima, Nicolas; Vermard, Youen; Castonguay, M.; Rivot, E.. |
| Using Lagrangian simulations, based on circulation models over three different hydroclimatic periods in the last 45 years in the North Atlantic Ocean, the trans-Atlantic migration of the European eel Anguilla anguilla leptocephali was simulated via the passive drift of particles released in the spawning area. Three different behaviours were modelled: drifting at fixed depth, undergoing a vertical migration or choosing the fastest currents. Simulations included mortality hypotheses to estimate a realistic mean migration duration and relative survival of A. anguilla larvae. The mean migration duration was estimated as 21 months and the mortality rate as 3 center dot 8 per year, i.e. < 0 center dot 2% of A. anguilla larvae may typically survive the... |
| Tipo: Text |
Palavras-chave: Migration duration; Leptocephalus mortality; Lagrangian modelling. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6614.pdf |
| |
|
|
| 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 |
| |
| Registros recuperados: 63 | |
|
|
|
