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  • 1
    Online Resource
    Online Resource
    EDP Sciences ; 2009
    In:  Aquatic Living Resources Vol. 22, No. 2 ( 2009-04), p. 119-1
    In: Aquatic Living Resources, EDP Sciences, Vol. 22, No. 2 ( 2009-04), p. 119-1
    Type of Medium: Online Resource
    ISSN: 0990-7440 , 1765-2952
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2009
    detail.hit.zdb_id: 2019083-9
    detail.hit.zdb_id: 291280-6
    SSG: 12
    SSG: 21,3
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  • 2
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2006
    In:  The Journal of the Acoustical Society of America Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3017-3017
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3017-3017
    Abstract: Multibeam echo-sounders and sonars are increasingly used in fisheries acoustics for studying school structure and behavior and for abundance estimation. However, data quality and a poor signal-to-noise ratio obtained with the existing multibeam echo-sounders preclude quantitative biomass estimation as carried out with the traditional single beam echo-sounders. In order to overcome these shortcomings, Ifremer and Simrad AS started in 2003 the development of the new and highly flexible calibrated multibeam echo-sounder ME70 designed for studying a wide range of scientific questions. This paper will present the full functionalities of the ME70 and preliminary results obtained with the system installed onboard the research vessel Thalassa. It will also provide first indications of its performance. Data have been collected on small pelagic fish species in the bay of Biscay, using simultaneously the traditional single beam echo-sounders and the ME70 with different beam configurations. Preliminary comparisons of fish school descriptors and biomass estimates based on single- and multibeam data allow us to quantify the effect of the gain in sampling coverage and the high angular resolution of the new system.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2006
    detail.hit.zdb_id: 1461063-2
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  • 3
    In: ICES Journal of Marine Science, Oxford University Press (OUP), Vol. 62, No. 8 ( 2005-01-01), p. 1647-1664
    Abstract: We present a method for combining individual indicator results into a comprehensive diagnostic of fishing impacts on fish populations and communities. A conceptual framework for interpreting combined trends in a set of simple indicators is proposed, relying beforehand on qualitative expectations anchored in ecological theory. The initial state of the community is first assessed using published information. Which combinations of trends are acceptable or undesirable is decided, depending on the initial status. The indicators are then calculated from a time-series and their time trends are estimated as the slopes of linear models. Finally, the test results are combined within the predefined framework, providing a diagnostic on the dynamics of fishing impacts on populations and communities. The method is demonstrated for nine coastal and shelf-sea fish communities monitored by French surveys. Most communities were persistently or increasingly impacted by fishing. In addition, climate change seems to have contributed to changes in East Atlantic communities. Cet article propose une méthode utilisant des indicateurs pour élaborer un diagnostic sur les effets de la pêche sur les populations et les peuplements de poissons. Un cadre conceptuel permet d'interpréter les tendances conjointes d'indicateurs à partir de la théorie écologique. L'état initial du peuplement est d'abord évalué sur la base d'informations publiées. En fonction de l'état initial et des objectifs de gestion, les combinaisons des tendances sont qualifiées d'indésirables ou satisfaisantes. Les indicateurs sont ensuite estimés à partir de données de campagnes de pêches scientifiques: abondance et longueur moyenne d'une sélection de populations, nombre, biomasse totale, poids moyen et longueur moyenne dans le peuplement, et la pente du spectre de taille multispécifique. Les tendances temporelles de ces indicateurs sont testées au moyen d'un modèle linéaire, et les résultats des tests sont combinés en un diagnostic final. La méthode est mise en œuvre pour neuf peuplements de poissons côtiers et du plateau continental, suivis par des campagnes françaises. Il en résulte que la plupart de ces peuplements sont affectés par la pêche de manière stationnaire ou croissante. Par ailleurs, les changements climatiques dans l'Atlantique Nord-Est contribuent aussi à des modifications dans les peuplements de poissons de cette région.
    Type of Medium: Online Resource
    ISSN: 1095-9289 , 1054-3139
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2005
    detail.hit.zdb_id: 2463178-4
    detail.hit.zdb_id: 1468003-8
    detail.hit.zdb_id: 29056-7
    SSG: 12
    SSG: 21,3
    Location Call Number Limitation Availability
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