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    • Calibration reflector 

      Foote, Kenneth G. (ICES CM Documents;1989/B:4, Working paper, 1989)
      Calibration of scientific echo sounders and integrators entails, inter alia, measurement of the dynamic range. This can be done by repeating on-axis measurements of echoes from each of two different standard targets. ...

    • Can subjective evaluation of echograms improve correlation between bottom trawl and acoustic densities? 

      Godø, Olav Rune; Hjellvik, Vidar; Greig, Tony; Beare, Douglas (ICES CM documents, Working paper, 2004)
      Direct comparison of acoustic densities and trawl catches involves fundamental difficulties related to species and size selectivity of the trawl and efficiency of the acoustic instrumentation. In some surveys, therefore, ...

    • Can the precision of bottom trawl indices be increased by using simultaneously collected acoustic data? The Barents Sea experience 

      Hjellvik, Vidar; Godø, Olav Rune; Tjøstheim, Dag (ICES CM documents, Conference object, 2006)

    • Can trawling effort be identified from satellite-based VMS data? 

      Salthaug, Are (ICES CM documents, Working paper, 2006)
      Data from satellite-based vessel monitoring systems (VMS) can, in principle, be used to measure fishing effort with a high spatiotemporal resolution. However, it can be difficult to separate between fishing activity and ...

    • The capelin assessment model: a documentation 

      Tjelmeland, Sigurd (PINRO-IMR Symposium, Conference object, 1985)
      The mathematical model used for management of the Barents Sea is documented. The model is used for predicting the evolution of the stock to evaluate the consequence of various catch quotas.

    • Capture and handling of fish for electronic tagging - a review and a new non-intrusive capture method. 

      Holm, Marianne; Arnold, Geoff P.; Holst, Jens Christian; Midling, Kjell (ICES CM documents, Working paper, 1999)
      While tagging procedures are described in details the capture and handling of experimental fish prior to tagging is not given the same attention in most papers. However, traumas that originate from the capture and handling ...

    • Capture techniques for wrasse (Labridae) 

      Bjordal, Åsmund (ICES CM Documents;1993/B:22, Working paper, 1993)
      An increasing demand for wrasse used as cleaner-fish for louse control in salmon farming has led to a new fishery for different wrasse species - particularly goldsinny, rock-cook and corkwing wrasse. This paper describes ...

    • Catch comparison between rockhoppers and bobbins ground gear on the Norwegian bottom sampling trawl 

      Engås, Arill; Jacobsen, Jan Arge; Soldal, Aud Vold (ICES CM Documents;1988/B:31, Working paper, 1988)
      In a study aimed at improving the reliability of the Norwegian bottom sampling trawl, comparative fishing between standard bobbins gear and rockhopper ground gear were carried out in the Barents Sea. The catch ratios ...

    • The catching efficiency of cod gillnets with different hanging ratio (E) and different floatline buoyancy. 

      Angelsen, Karl Kr.; Haugen, Kjeld; Floen, Svein (ICES CM Documents;1979/B:19, Working paper, 1979)
      The floatline buoyancy seems to influence the catching efficiency of cod gillnets. Trials with different byoyancies in cod gillnet fishing in Northern Norway gave the best catches with a buoyancy of about 65 grammes per ...

    • Catfish - King of the sea 

      Godø, Olav Rune; Huse, Irene; Michalsen, Kathrine (ICES CM Documents;1995/B:16, Working paper, 1995)
      During an acoustic tagging experiment on cod in the Barents Sea in March 1995 a hierarchy between different fish species was revealed, and the catfish (Anarhichas sp.) was observed to be dominant in relation to cod and ...

    • Changes in acoustic abundance - a signal indicatior for stock dynamics for cod (Gadus morhua) 

      Godø, Olav Rune; Ona, Egil (ICES CM documents, Working paper, 1999)
      To be able to take the proper and timely management actions, it is crucial to reliably defect major changes in trends of fish stock abundance. For the assessment of Northeast Arctic cod, the Norwegian bottom trawl survey ...

    • Codend selectivity of the Danish seine investigated by the trouser trawl method 

      Isaksen, Bjørnar; Larsen, Roger B. (ICES CM Documents;1988/B:28, Working paper, 1988)
      During June 1986 codend selectivity of the Danish seine was measured using both diamond mesh codends and square mesh codends. Comparisons between different codends were made by the trouser trawl method, having two ...

    • Coincidence echo statistics 

      Foote, Kenneth G. (ICES CM Documents;1994/B:40, Working paper, 1994)
      Two scatterers at similar range give an echo which may appear to be due to a single scatterer. Methods for determining target strength that depend on resolving single scatterers may fail in this instance. Statistics associated ...

    • Combined algorithms for detection of acoustic categories 

      Korneliussen, Rolf J.; Ona, Egil (ICES CM Documents;2004/R:38, Working paper, 2004)
      There is a current desire to harvest marine resources by managing total marine ecosystems rather than single species of the ecosystems. By means of algorithms applied on high-quality multi-frequency acoustic data, species, ...

    • Comparative analysis of split beam data 

      Kieser, Robert; Ona, Egil (ICES CM Documents;1988/B:44, Working paper, 1988)
      Split beam data can provide high quality, in situ, fish target strength estimates, however a careful calibration is required to realize this potential. In same cases a standard target has been used to make a large number ...

    • Comparison between "underway" and "on station" acoustic measurements made during bottom trawl surveys 

      Nicolas, Bez; Mireille, Bouleau; Godø, Olav Rune; Armstrong, Mike; Gerritsen, Hans D.; Vérin, Yves; Massé, Jacques; Méhault, Sonia (ICES CM Documents;2002/J:3, Working paper, 2002)
      It becomes in many cases, routine, to collect acoustic data during bottom trawl surveys, both during and between trawls providing “on station” and “underway” acoustic data. Still, the combination of trawl and acoustic data ...

    • Comparison of equal-area cylindrical and circular piston transducers 

      Foote, Kenneth G. (ICES CM Documents;1994/L:29, Working paper, 1994)
      Design of sondes for in situ measurement of zooplankton or other scatterers requires choosing among alternative transducer geometries. This contribution addresses the problem of choosing between cylindrical and circular ...

    • Comparison of Northeast Atlantic mackerel (Scomber scombrus) distribution patterns in the Norwegian Sea using lidar, sonar, and trawl 

      Tenningen, Eirik; Godø, Olav Rune; Iversen, Svein A.; Slotte, Aril; Hjellvik, Vidar; Torkelsen, Terje (ICES CM documents, Working paper, 2003)
      In July 2002 the Institute of Marine Research (IMR), Bergen mapped the distribution and density of mackerel in the Norwegian Sea using lidar, sonar and trawl. A major objective was to test the efficiency of the lidar as ...

    • Comparison of Norwegian and Russian trawl performance: Preliminary analysis of cod data 

      Mehl, Sigbjørn (Working paper, 1998)

    • Comparison of two 120-kHz split-beam transducers 

      Foote, Kenneth G. (ICES CM Documents;1991/B:31, Working paper, 1991)
      The performance of two 120-kHz split-beam transducers is compared through the following measures: relative power level, directivity index, relative source level, and reverberation index or equivalent beam angle. Sidelobe ...