Blar i ICES CM documents authored by IMR scientists (1949-2011) på forfatter "Handegard, Nils Olav"
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A vessel specific bias in echo sounder recordings during trawling
Handegard, Nils Olav; Hjellvik, Vidar (ICES CM Documents;2004/R:35, Working paper, 2004) -
Adaptive management of living marine resources by integrating different data sources and key ecological processes (ADMAR): A joint effort by IMR and CEES
Handegard, Nils Olav; Stenseth, Nils Christian; Dankel, Dorothy Jane; Durant, Joël M.; Eikeset, Anne Maria; Enberg, Katja; Hjermann, Dag Ø.; Huse, Geir; Pennington, Michael; Skern-Mauritzen, Mette; Stige, Leif Christian; Subbey, Samuel; Vølstad, Jon Helge (ICES CM documents;2010/R:26 Poster;, Working paper, 2010-09) -
Correcting for avoidance in acoustic abundance estimates for herring using a generalized linear model
Hjellvik, Vidar; Handegard, Nils Olav; Ona, Egil (ICES CM documents, Working paper, 2006)When a research vessel passes over a herring school or layer, the herring may avoid the vessel by swimming downwards and horizontally. The fish may also change its orientation, which may alter its mean target strength. ... -
Designing an Ocean Mid-trophic Automatic Acoustic Sampler (MAAS) - thoughts on how to include echo sounder observatories in ecosystem models
Handegard, Nils Olav; Domokos, Réka; Godø, Olav Rune; Jouanno, Julien; Kloser, Rudy; Lehodey, Patrick; Maury, Olivier; Senina, Inna (ICES CM documents;2009/I:21, Working paper, 2009)Echo sounders are a widely used tool for observing marine ecosystems. Traditionally, carefully designed surveys are used to integrate biomass to a global estimate, which is coupled to traditional stock assessment models. ... -
Modeling fish reaction to vessel noise, the significance of the reaction thresholds
Handegard, Nils Olav; Ona, Egil (ICES CM documents, Working paper, 2001)A simple model of fish reaction to vessel noise is made. The fish are assumed to swim directly away from the noise source. The main noise source is assumed to be the propeller. Parameters for endurance and swimming speed ... -
Studying the relationship between spatial fish distributions and trawl catches
Trenkel, Verena M.; Godø, Olav Rune; Handegard, Nils Olav; Patel, Ruben (ICES CM Documents;2004/R:26, Working paper, 2004)We propose an approach for studying the relationship between spatial fish distributions and the distribution of numbers in trawl catches. Individual spatial fish distributions are derived from acoustics data collected with ... -
The effective swept volume of a bottom trawl
Handegard, Nils Olav; Tjøstheim, Dag (ICES CM Documents;2004/R:7, Working paper, 2004)The reaction of individual fish towards an approaching trawling vessel has previously been measured using target-tracking methods. In this paper these measured velocities are fitted to a deterministic mean behaviour ... -
Towards Operational Management Of Pelagic Ecosystems
Lehodey, Patrick; Senina, Inna; Calmettes, Beatriz; Royer, Francois; Gaspar, Philippe; Abécassis, Mélanie; Polovina, Jeffrey; Parker, Denise; Domokos, Réka; Hernandez, Olga; Dessert, Morgane; Kloser, Rudy; Young, Jock; Lutcavage, Molly; Handegard, Nils Olav; Hampton, John (ICES CM documents;2010/A:04, Working paper, 2010)Satellite data and operational ocean models provide the necessary inputs for ecosystem models of the lower to mid- and upper trophic levels. One key explanatory variable that is usually missing to understand the dynamics ...