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Auteur Joo, R.; Bertrand, S.; Tam, J.; Fablet, R. url  doi
openurl 
  Titre Hidden Markov Models: The Best Models for Forager Movements? Type Article scientifique
  Année 2013 Publication Revue Abrégée PLoS ONE  
  Volume 8 Numéro 8 Pages  
  Mots-Clés  
  Résumé One major challenge in the emerging field of movement ecology is the inference of behavioural modes from movement patterns. This has been mainly addressed through Hidden Markov models (HMMs). We propose here to evaluate two sets of alternative and state-of-the-art modelling approaches. First, we consider hidden semi-Markov models (HSMMs). They may better represent the behavioural dynamics of foragers since they explicitly model the duration of the behavioural modes. Second, we consider discriminative models which state the inference of behavioural modes as a classification issue, and may take better advantage of multivariate and non linear combinations of movement pattern descriptors. For this work, we use a dataset of \textgreater200 trips from human foragers, Peruvian fishermen targeting anchovy. Their movements were recorded through a Vessel Monitoring System (∼1 record per hour), while their behavioural modes (fishing, searching and cruising) were reported by on-board observers. We compare the efficiency of hidden Markov, hidden semi-Markov, and three discriminative models (random forests, artificial neural networks and support vector machines) for inferring the fishermen behavioural modes, using a cross-validation procedure. HSMMs show the highest accuracy (80%), significantly outperforming HMMs and discriminative models. Simulations show that data with higher temporal resolution, HSMMs reach nearly 100% of accuracy. Our results demonstrate to what extent the sequential nature of movement is critical for accurately inferring behavioural modes from a trajectory and we strongly recommend the use of HSMMs for such purpose. In addition, this work opens perspectives on the use of hybrid HSMM-discriminative models, where a discriminative setting for the observation process of HSMMs could greatly improve inference performance.  
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  Numéro d'Appel (up) LL @ pixluser @ collection 260  
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Auteur Le Manach, F.; Chaboud, C.; Copeland, D.; Cury, P.; Gascuel, D.; Kleisner, K.M.; Standing, A.; Sumaila, U.R.; Zeller, D.; Pauly, D. url  doi
openurl 
  Titre European Union’s Public Fishing Access Agreements in Developing Countries Type Article scientifique
  Année 2013 Publication Revue Abrégée PLoS ONE  
  Volume 8 Numéro 11 Pages  
  Mots-Clés  
  Résumé The imperative to increase seafood supply while dealing with its overfished local stocks has pushed the European Union (EU) and its Member States to fish in the Exclusive Economic Zones of other countries through various types of fishing agreements for decades. Although European public fishing agreements are commented on regularly and considered to be transparent, this is the first global and historical study on the fee regime that governs them. We find that the EU has subsidized these agreements at an average of 75% of their cost (financial contribution agreed upon in the agreements), while private European business interests paid the equivalent of 1.5% of the value of the fish that was eventually landed. This raises questions of fisheries benefit-sharing and resource-use equity that the EU has the potential to address during the nearly completed reform of its Common Fisheries Policy.  
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  Numéro d'Appel (up) LL @ pixluser @ collection 269  
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Auteur GAERTNER, J.-C.; MAIORANO, P.; Mérigot, B.; COLLOCA, F.; POLITOU, C.-Y.; GIL DE SOLA, L.; BERTRAND, J.; MURENU, M.; DURBEC, J.-P.; KALLIANIOTIS, A.; MANNINI, A. url  openurl
  Titre Large-Scale Diversity of Slope Fishes: Pattern Inconsistency between Multiple Diversity Indices Type Article scientifique
  Année 2013 Publication Revue Abrégée Plos One  
  Volume 8 Numéro 7 Pages  
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  Résumé Large-scale studies focused on the diversity of continental slope ecosystems are still rare, usually restricted to a limited number of diversity indices and mainly based on the empirical comparison of heterogeneous local data sets. In contrast, we investigate large-scale fish diversity on the basis of multiple diversity indices and using 1454 standardized trawl hauls collected throughout the upper and middle slope of the whole northern Mediterranean Sea (36 degrees 3' – 45 degrees 7' N; 5 degrees 3'W – 28 degrees E). We have analyzed (1) the empirical relationships between a set of 11 diversity indices in order to assess their degree of complementarity/redundancy and (2) the consistency of spatial patterns exhibited by each of the complementary groups of indices. Regarding species richness, our results contrasted both the traditional view based on the hump-shaped theory for bathymetric pattern and the commonly-admitted hypothesis of a large-scale decreasing trend correlated with a similar gradient of primary production in the Mediterranean Sea. More generally, we found that the components of slope fish diversity we analyzed did not always show a consistent pattern of distribution according either to depth or to spatial areas, suggesting that they are not driven by the same factors. These results, which stress the need to extend the number of indices traditionally considered in diversity monitoring networks, could provide a basis for rethinking not only the methodological approach used in monitoring systems, but also the definition of priority zones for protection. Finally, our results call into question the feasibility of properly investigating large-scale diversity patterns using a widespread approach in ecology, which is based on the compilation of pre-existing heterogeneous and disparate data sets, in particular when focusing on indices that are very sensitive to sampling design standardization, such as species richness.  
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  Notes <p>The following values have no corresponding Zotero field:<br />Author Address: Univ Polynesie Francaise, UPF,IRD,Ifremer,ILM, UMR EIO 241, Faaa, Tahiti, Fr Polynesia.<br />Author Address: Ctr Arue, IRD, UPF,IRD,Ifremer,ILM, UMR EIO 241, Papeete, Tahiti, Fr Polynesia.<br />Author Address: Univ Bari, Dept Zool, Bari, Italy.<br />Author Address: Ctr Rech Halieut Mediterrane enne & Trop, UMR Ecosyst Marins Exploites 212, Sete, France.<br />Author Address: Univ Roma La Sapienza, Dept Anim & Human Biol, I-00185 Rome, Italy.<br />Author Address: Inst Marine Biol Resources, Hellen Ctr Marine Res, Ellinikon, Greece.<br />Author Address: Ctr Oceanog Malaga IEO, Fuengirola, Malaga, Spain.<br />Author Address: IFREMER, Dept Ecol & Modeles Halieut, Nantes, France.<br />Author Address: Univ Cagliari, Dipartimento Biol Anim & Ecol, Cagliari, Italy.<br />Author Address: Univ Aix Marseille, UMR MIO, Ctr Oceanol Marseille, Marseille, France.<br />Author Address: Natl Agr Res Fdn, Fisheries Res Inst, Kavala, Greece.<br />Author Address: Univ Genoa, Dip Te Ris, Genoa, Italy.<br />PB – Public Library Science</p> Approuvé pas de  
  Numéro d'Appel (up) LL @ pixluser @ collection 287  
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Auteur Aires, T.; Serrão, E.A.; Kendrick, G.; Duarte, C.M.; Arnaud-Haond, S. url  doi
openurl 
  Titre Invasion Is a Community Affair: Clandestine Followers in the Bacterial Community Associated to Green Algae, Caulerpa racemosa, Track the Invasion Source Type Article scientifique
  Année 2013 Publication Revue Abrégée PLoS ONE  
  Volume 8 Numéro 7 Pages  
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  Editeur Lieu de Publication Éditeur Verbruggen, H.  
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  Numéro d'Appel (up) LL @ pixluser @ collection 303  
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Auteur Tremblay, Y.; Robinson, P.W.; Costa, D.P. url  openurl
  Titre A parsimonious approach to modeling animal movement data Type Article scientifique
  Année 2009 Publication Revue Abrégée PLoS ONE  
  Volume 4 Numéro 3 Pages  
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  Résumé Animal tracking is a growing field in ecology and previous work has shown that simple speed filtering of tracking data is not sufficient and that improvement of tracking location estimates are possible. To date, this has required methods that are complicated and often time-consuming (state-space models), resulting in limited application of this technique and the potential for analysis errors due to poor understanding of the fundamental framework behind the approach. We describe and test an alternative and intuitive approach consisting of bootstrapping random walks biased by forward particles. The model uses recorded data accuracy estimates, and can assimilate other sources of data such as sea-surface temperature, bathymetry and/or physical boundaries. We tested our model using ARGOS and geolocation tracks of elephant seals that also carried GPS tags in addition to PTTs, enabling true validation. Among pinnipeds, elephant seals are extreme divers that spend little time at the surface, which considerably impact the quality of both ARGOS and light-based geolocation tracks. Despite such low overall quality tracks, our model provided location estimates within 4.0, 5.5 and 12.0 km of true location 50% of the time, and within 9, 10.5 and 20.0 km 90% of the time, for above, equal or below average elephant seal ARGOS track qualities, respectively. With geolocation data, 50% of errors were less than 104.8 km (<0.94°), and 90% were less than 199.8 km (<1.80°). Larger errors were due to lack of sea-surface temperature gradients. In addition we show that our model is flexible enough to solve the obstacle avoidance problem by assimilating high resolution coastline data. This reduced the number of invalid on-land location by almost an order of magnitude. The method is intuitive, flexible and efficient, promising extensive utilization in future research.  
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  Numéro d'Appel (up) LL @ pixluser @ collection 49  
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