• Acoustic abundance estimation of the stock of Norwegian spring spawning herring, winter 1995- 1996 

      Foote, Kenneth G.; Ostrowski, Marek; Røttingen, Ingolf; Engås, Arill; Hansen, Kaare A.; Hauge, Kjellrun Hiis; Skeide, Roar L.; Slotte, Aril; Torgersen, Øyvind (ICES CM Documents;1996/H:33, Working paper, 1996)
      Standard echo integration methodology has been applied to the stock of Norwegian spring spawning herring (Clupea harengus) wintering in the Ofotfjord-Tysfjord-Vestfjord system during late autumn 1995 and early winter ...
    • In situ target strength observations on haddock 

      Ona, Egil; Hansen, Kaare A. (ICES CM Documents;1986/B:39, Working paper, 1986)
      In situ target strength measurements of ideally resolved haddock have been made using the ES-400 split-beam echo sounder. The measurements are compared with the mean target strength obtained simultaneously by counting ...
    • Intercalibration between R/V "Johan Hjort" and R/V "Pinro", 23 march 1991 

      Hansen, Kaare A.; Dorchenkov, Alexander E. ([Toktrapport/Havforskningsinstituttet];, Working paper, 1991-05-14)
    • Intercalibration of acoustic systems onboard R/V "Johan Hjort" and R/V "Pinro" 

      Dorchenkov, Alexander E.; Hansen, Kaare A. (ICES CM Documents;1992/B:17, Working paper, 1992)
      Inter-ship calibration is a comparison between integrator output of two or more ships sailing over the same fish aggregations. Although it is a relative measurement, it is highly desireable whenever research vessels ...
    • More on the frequency dependence of target strength of mature herring 

      Foote, Kenneth G.; Hansen, Kaare A.; Ona, Egil (ICES CM Documents;1993/B:30, Working paper, 1993)
      The hibernating stock of Norwegian spring-spawning herring has been acoustically surveyed in a fjord system in northern Norway in December 1992. The survey frequencies are 18, 38, 120, and 200 kHz. When the corresponding ...
    • New towed transducer concept 

      Hansen, Kaare A. (ICES CM Documents;1988/B:59, Working paper, 1988)
      The history of towed transducer applications at the Institute of Marine Research, Bergen, is reviewed. Advantages and disadvantages of several designs are summarized. To improve performance significantly, a new system ...
    • On the frequency dependence of target strength of mature herring 

      Foote, Kenneth G.; Hansen, Kaare A.; Ona, Egil (ICES CM Documents;1992/B:10, Working paper, 1992)
      Mature herring (Clupea harengus), hibernating in Ofotfjord in December 1991, was measured simultaneously at each of three frequencies: 18, 38, and 120 kHz. Measurements of the mean volume backscattering coefficient were ...