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| Registros recuperados: 129 | |
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| Rodríguez‐ezpeleta, Naiara; Díaz‐arce, Natalia; Walter, John F; Richardson, David E; Rooker, Jay R; Nøttestad, Leif; Hanke, Alex R; Franks, James S; Deguara, Simeon; Lauretta, Matthew V; Addis, Piero; Varela, Jose Luis; Fraile, Igaratza; Goñi, Nicolas; Abid, Noureddine; Alemany, Francisco; Oray, Isik K; Quattro, Joseph M; Sow, Fambaye N; Itoh, Tomoyuki; Karakulak, F Saadet; Pascual‐alayón, Pedro J; Santos, Miguel N; Tsukahara, Yohei; Lutcavage, Molly; Fromentin, Jean-marc; Arrizabalaga, Haritz. |
| Effective sustainable management of marine fisheries requires that assessed management units (that is, fish stocks) correspond to biological populations. This issue has long been discussed in the context of Atlantic bluefin tuna (ABFT, Thunnus thynnus) management, which currently considers two unmixed stocks but does not take into account how individuals born in each of the two main spawning grounds (Gulf of Mexico and Mediterranean Sea) mix in feeding aggregations throughout the Atlantic Ocean. Using thousands of genome‐wide molecular markers obtained from larvae and young of the year collected at the species’ main spawning grounds, we provide what is, to the best of our knowledge, the first direct genetic evidence for “natal homing” in ABFT. This has... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00595/70710/68917.pdf |
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| Le Fevre-lehoerff, Geneviève; Ibanez, Frédéric; Poniz, Paola; Fromentin, Jean-marc. |
| Planktonic time series collected since 1975 off Gravelines, France, were analysed in the context of climatic changes. Principal component analysis and the cumulative sums method wereapplied to 30 data sets which included meteorological and hydrological parameters and planktonic descriptors. Eight groups of biological descriptors were linked to external parameters. The study of winds highlighted the importance of cyclonic and anticyclonic influences. Seven year cycles appeared clearly in air temperature and in species abundance with different trophic levels for species such as Ternora longicornis, Oikopleura dioica and Sagitta setosa, whereas an 11 yr cycle appeared for Pseudocalanus minutus. A 3 to 4 yr cycle was detected for atmospheric pressure,... |
| Tipo: Text |
Palavras-chave: Time series; Zooplankton; Meteorology; Hydrology; Southern North Sea. |
| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00033/14455/11757.pdf |
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| Royer, Francois; Fromentin, Jean-marc. |
| This paper provides an exploratory analysis aiming to seek whether the colour of environmental noise theory could help in understanding the intriguing reproductive strategy of Atlantic bluefin tuna (BFT). A frequency-based approach based on spectral exponents, f(beta) with beta < 0, is chosen and applied on 10 biogeographical provinces covering the North Atlantic. The major BFT spawning area, i.e. the Mediterranean Sea, was the only one to display a pink power spectrum, whereas open ocean regions displayed more reddened fluctuations, i.e. greater variance at low frequencies. Environmental noise in the Mediterranean could, thus, offer more favourable characteristics on the long-term than the open ocean. The implications of these findings are discussed in... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Spectral analysis; Spawning; Sea surface temperature; Environmental noise. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2437.pdf |
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| Fromentin, Jean-marc; Restrepo, Victor. |
| At the ICCAT symposium on bluefin tuna that held in Santander in April 2008, Tangen et al.(2009) presented a first quantification of the fishing effort deployed by the Norwegian fishery targeting bluefin tuna in the North Sea and Norwegian Sea. Using a year-class curve analysis on the Norwegian CPUE, this document presents the first estimates of mortality rates of Atlantic bluefin tuna that migrated north from the mid-1950s to the late 1970s. The results indicate that bluefin tuna would have experienced a total mortality rate (Z) of 0.2 to 0.4 yr-1 (i.e. F at around 0.3 yr-1) during the late 1950s, 0.2 yr-1 during the 1960s and 0.1 yr-1 afterwards (assuming M=0.1 yr-1). These results appear to be rather robust and consistent with the VPA estimates from the... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Fishing and natural mortalities; Year-class curves; Stock assessment. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00192/30294/28783.pdf |
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| Fromentin, Jean-marc; Planque, Benjamin; Thebaud, Olivier. |
| This document discusses the possible evolutions of IFREMER's research activities in support of the ecosystem-based approach to fisheries management (EAF). It results from an investigation undertaken within the programme "Ecosystem approach to the management of fish resources" (DÉMarche écOSysTÉMique pour une gestion des Ressources Halieutiques"). The first part of the document presents the background to the development of the EAF, particularly the increasing number of reports of resource over-exploitation, the issue of sustainability of exploitation systems, the diversification of uses of marine resources, the key role of governance and the degradation of the state of the ecosystems. The second part aims at synthesizing the challenges faced by research... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/rapport-2567.pdf |
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| Fromentin, Jean-marc; Fonteneau, Alain; Restrepo, Victor. |
| During the last SCRS plenary meeting, the sub-committee on environment suggested to present a document on the ‘Ecosystem Approach to Fisheries’ (EAF). This document firstly recalls the general scientific and institutional background of EAF, then we propose a synoptic view of EAF, including four main domains: governance, exploitation, resources and impacts on ecosystems. The way that EAF is tackled within the various tuna commissions is then summarised. Finally, we rapidly examine the way the SCRS could cope with EAF issues and we suggest to merge the sub-committee on environment with this on by-catch into a single subcommittee on ecosystem. |
| Tipo: Text |
Palavras-chave: Ecosystem; Resources; Exploitation; Governance; Environment; By-catch. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00192/30334/28809.pdf |
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| Fromentin, Jean-marc. |
| In the recent past, it has been put forward that recruitment of the North Atlantic albacore, East Atlantic bluefin tuna and North Atlantic swordfish could be related to the North AtlanticOscillation (NAO). In this document, the biological processes behind the NAO/recruitmentrelationship are further investigated. Then, the possible relationship between the East Atlanticbluefin tuna recruitment was re-investigated. The linear relationship appeared to be only due to the low frequency signal, both BFT recruitment and NAO displaying a pseudo-cyclic upwardtrend, but year-to-year fluctuations were not synchronous. The superposed epoch analysis, thatwas conducted to test for possible non-linear and non-monotonous relationship did not reveal any clear connection.... |
| Tipo: Text |
Palavras-chave: North Atlantic Oscillation; Recruitment; Bluefin; Albacore; Swordfish; Migration patterns; Time series; Spatially disaggregated data. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00194/30498/28908.pdf |
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| Fromentin, Jean-marc. |
| The robustness of ADAPT conceming the 1996 SCRS bluefin tuna stock assessment for the northeast Atlantic is tested through various sensitivity analyses on the main technical specifications. We aIso computed simple VPA in order to investigate the reIiability of the trends in the recruitment estimates and the stock estimates of ages 2-5 and 8+. It is concluded that: (i) the estimates of the 1996 SCRS working group are very sensitive to the technical specifications on the F-ratios (which determine F for the last group), natural mortality as well as to under-reporting on the catch data; and (ii) the increasing trends of the recruitment and the young ages as well as the strong decline in ages 8 + should be treated with caution. |
| Tipo: Text |
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| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00194/30556/28972.pdf |
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| Kell, L; Fromentin, Jean-marc. |
| In this study, we examine the performances of current stock assessment methods with respect to their ability to (i) provide estimates of maximum sustainable yield (MSY), FMSY, and BMSY and (ii) assess stock status and exploitation level relative to MSY targets. The robustness of the current International Commission for the Conservation of Atlantic Tunas (ICCAT) management strategy is then evaluated with respect to uncertainty about the true population dynamics and contrasted with a simpler management strategy based solely on a size limit. Reference points are more robust to dynamic uncertainty than the estimates of absolute values and trends in F and spawning stock biomass. However, their performances depend on the underlying dynamics (they perform better... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3534.pdf |
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| 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 |
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| Fromentin, Jean-marc; Planque, Benjamin. |
| The influence of the North Atlantic Oscillation (NAO) on 2 major zooplankton species ofthe eastern North Atlantic and the North Sea, Calanus finmarchicus and C. helgolandicus (Copepoda, Calanoida), was investigated. Our results confirm that from December to April, west wind stress (WWS) intensity and temperature are strongly related to the NAO. If these results were expected, more striking were the close relationships between NAO and Calanus species abundance. Fluctuations in abundance of C. finmarchicus mainly result from the combination of 2 factors, both driven by the NAO: WWS effects on spring primary production and temperature. The case of C. helgolandicus is more complicated,as the links between this species and the NAO result from the combination of... |
| Tipo: Text |
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| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00033/14456/11758.pdf |
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| Ibanez, F; Fromentin, Jean-marc. |
| The typology of shapes of series (TSS) aims to gather together species having similar temporal patterns corresponding to different types of ecological behaviour. Each type of change, referred to as the ecological shape, is considered to reflect a particular demographic strategy (sudden pullulation of opportunistic species, fluctuations with environmental changes, etc.). This method which consists in the definition of four shape parameters and a classification among the series, taking into account these shape parameters, does not replace the usual statistical analyses, mainly multivariate ones, but precedes them. Such preliminary information is useful for the choice of the subsequent treatments, avoiding the need to analyse simultaneously species presenting... |
| Tipo: Text |
Palavras-chave: Times series; Ecological shape; Macrobenthic community; English Channel. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20384/18050.pdf |
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| Banaru, Daniela; Mellon, Capucine; Roos, David; Bigot, Jean-louis; Souplet, Arnauld; Jadaud, Angelique; Beaubrun, P.; Fromentin, Jean-marc. |
| The Gulf of Lions ecosystemwas described using the Ecopath mass-balancemodel to characterise its structure and functioning and to examine the effects of themultispecific fisheries operating in this area. The model is composed of 40 compartments, including 1 group of seabirds, 2 groups of etaceans, 18 groups of fish, 12 groups of invertebrates, 5 groups of primary producers, detritus and discards. Input datawere based on several recurrent scientific surveys, two alternative datasets for fishing data, stock assessment outputs, stomach content analyses and published information. Results showed that the functional groups were organised into five trophic levels with the highest one represented by dolphins, anglerfish, Atlantic bluefin tuna, European hake and... |
| Tipo: Text |
Palavras-chave: Gulf of Lions; Ecopath with Ecosim; Food web; Fishing impacts. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00116/22758/20614.pdf |
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| Druon, Jean-noel; Helaouet, Pierre; Beaugrand, Grégory; Fromentin, Jean-marc; Palialekis, Andreas; Hoepffner, Nicolas. |
| This study investigates the association between an index of mesozooplankton biomass, derived from the Continuous Plankton Recorder survey and satellite-derived productivity fronts in the North Atlantic. While chlorophyll-a content (CHL) is commonly described as a proxy for phytoplankton biomass, the size of productivity fronts estimated from the horizontal gradient of CHL appears to be directly linked to mesozooplankton biomass. Our results suggest that the lifespan of productivity fronts, which ranges from weeks to months, meets the time requirement of mesozooplankton to develop. The proposed indicator describes the daily distribution of mesozooplankton’s suitable feeding habitat. It also provides a coherent interpretation of the productivity front... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00486/59744/62843.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... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00011/12231/9029.pdf |
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| Bauer, Robert Klaus; Fromentin, Jean-marc; Demarcq, Herve; Bonhommeau, Sylvain. |
| We investigated the habitat utilization, vertical and horizontal behaviour of Atlantic bluefin tuna Thunnus thynnus (ABFT) in relation to oceanographic conditions in the northwestern Mediterranean Sea, based on 36 pop-up archival tags and different environmental data sets. Tags were deployed on early mature ABFT (127–255 cm) between July and November in 2007-2014, on the shelf area off Marseille, France. The data obtained from these tags provided 1643 daily summaries of ABFT vertical behaviour over 8 years of tag deployment. Based on a hierarchical clustering of this data, we could identify four principle daily vertical behaviour types, representing surface (≦10m) and subsurface (10–100 m) orientation, moderate (50–200 m) and deep (≧200m) diving behaviour.... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Habitat use; Spike dives; Fronts; Thermal stratification; Archival tags. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00382/49329/49709.pdf |
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| Brosset, Pablo; Le Bourg, Baptiste; Costalago, David; Banaru, Daniela; Van Beveren, Elisabeth; Bourdeix, Jean-herve; Fromentin, Jean-marc; Menard, Frederic; Saraux, Claire. |
| Since 2008, a severe decrease in size and body condition together with a demographic truncation has been observed in the sardine (secondarily in anchovy) population of the Gulf of Lions (NW Mediterranean Sea). In parallel, sprat biomass, which was negligible before, has increased tenfold. All of these changes have strongly affected the regional fisheries. Using trophic and isotopic data from contrasting periods of low versus high growth and condition, we investigated potential changes in diet and interspecific feeding interactions through time. Evidence of resource partitioning was found between sprat and both anchovy and sardine in 2004 and 2005. Since 2010, the isotopic niches of the 3 species have tended to overlap, suggesting higher risk of competition... |
| Tipo: Text |
Palavras-chave: Trophic ecology; Anchovy; Sardine; Sprat; Dietary overlap; NW Mediterranean. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00347/45822/45540.pdf |
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| Registros recuperados: 129 | |
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