Blar i The Ecosystems and Population Dynamics Programme på forfatter "Handegard, Nils Olav"

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    • Estimating tail-beat frequency using split-beam echosounders 

      Handegard, Nils Olav; Pedersen, Geir; Brix, Ole (Journal article; Peer reviewed, 2009-02-04)
      Data from a standard split-beam echosounder are used to estimate tail-beat frequency within a dense herring (Clupea harengus L.) layer. The data were collected by lowering a horizontally projecting 38 kHz split-beam ...

    • Guidelines towards an integrated ocean observation system for ecosystems and biogeochemical cycles 

      Claustre, Hervé; Antoine, David; Boehme, Lars; Boss, Emmanuel; D`Ortenzio, Fabrizio; D`Andon, Odile Fanton; Guinet, Christophe; Gruber, Nicolas; Handegard, Nils Olav; Hood, Maria; Johnson, Ken; Körtzinger, Arne; Lampitt, Richard; LeTraon, Pierre-Yves; Lequéré, Corinne; Lewis, Marlon; Perry, Mary-Jane; Platt, Trevor; Roemmich, Dean; Testor, Pierre; Sathyendranth, Shubba; Send, Uwe; Yoder, Jim (Journal article; Peer reviewed, 2009)
      The observation of biogeochemical cycles and ecosystems has traditionally been based on ship-based platforms. The obvious consequence is that the measured properties have been dramatically undersampled. Recent technological ...

    • Lateral-aspect target strength measurements of in situ herring (Clupea harengus) 

      Pedersen, Geir; Handegard, Nils Olav; Ona, Egil (Journal article; Peer reviewed, 2009-07)
      Surveys of schooling herring with the new multi-beam sonar (Simrad MS70) pose new challenges when converting the echo energy to estimates of biomass. Since the sonar projects horizontally, data and models of lateral-aspect ...

    • The sampling volume of trawl and acoustics: estimating availability probabilities from observations of tracked individual fish 

      Handegard, Nils Olav; Tjøstheim, Dag (Journal article; Peer reviewed, 2009-03-10)
      The effective sampling volume of trawl and acoustics is an important parameter in fish abundance estimation surveys. This paper presents a method to compute the probability of a fish being available to the bottom trawl and ...

    • Toward a Global Ocean Ecosystem Mid-trophic Automatic Acoustic Sampler (MAAS) 

      Handegard, Nils Olav; Demer, David A.; Kloser, Rudy; Lehodey, Patrick; Maury, Olivier; Simard, Yvard (Journal article; Peer reviewed, 2009-05-26)
      Despite their huge biomass and pivotal role, the mid-trophic levels of marine ecosystems are not generally subject to systematic monitoring. Data from such monitoring is crucial for parameterizing, validating, and constraining ...