• Acoustic assessment of Norwegian spring spawning herring in the wintering area, December 1995 and January 1995 

      Foote, Kenneth G.; Røttingen, Ingolf (ICES CM Documents;1995/H:9, Working paper, 1995)
      The abundance of the mature component of the stock of Norwegian spring spawning herring has been estimated based on a series of echo integration surveys. These were performed in the wintering area of Ofotfjord, Tysfjord, and ...
    • Acoustic sampling volume for cod 

      Foote, Kenneth G. (ICES CM Documents;1989/B:5, Working paper, 1989)
      This is expressed through the effective equivalent beam angle * for cod as represented by measurements of the tilt angle dependence of target strength. The functional form of * is approximated for each of several behaviour ...
    • Advances in Bergen Echo Integrator 

      Korneliussen, Rolf J. (ICES CM Documents;1993/B:28, Working paper, 1993)
      The Bergen Echo Integrator (BEl) is a software system designed for convenient postprocessing of echo sounder data. BEl is realized in international standards and is essentially machine independent. Development of BEl for ...
    • A vessel specific bias in echo sounder recordings during trawling 

      Handegard, Nils Olav; Hjellvik, Vidar (ICES CM Documents;2004/R:35, Working paper, 2004)
    • Avoidance reactions of herring to a survey vessel, studied by scanning sonar 

      Ona, Egil; Toresen, Reidar (ICES CM Documents;1988/H:46, Working paper, 1988)
      The behavioural response of a shallow herring layer to a steaming vessel has been studied by the use of a high-resolution scanning sonar technique. When the vessel was completely darkened, no significant reaction important ...
    • Bad-weather calibration of split-beam echo sounder systems 

      Foote, Kenneth G. (ICES CM Documents;1990/B:22, Working paper, 1990)
      A condition for standard-target calibration is stability of the sonar platform and target rig. This condition cannot always be met, nor need it be when the transducer has a split-beam function. Since the position of ...
    • Bergen Echo Integrator: An Introduction 

      Knudsen, Hans Petter (ICES CM Documents;1989/B:9, Working paper, 1989)
      The design of a new echo integrator system is outlined. The B.E.I. is based on preprocessed data from the new SIMRAD EK500 scientific acoustic measurement system. Raw data are displayed and interpreted on a graphics ...
    • 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. ...
    • 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 ...
    • 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 ...
    • Cylindrical sonar design for fish echo surveying 

      Foote, Kenneth G. (ICES CM Documents;1988/B:3, Working paper, 1988)
      Most applications of echo integration involve use of a fixed single-beam transducer that is rather narrow and downwards-oriented. It is often desired to sense fish in other directions, for example, to assess components ...
    • Detailed in situ target strength measurements of 0-group cod 

      Ona, Egil (ICES CM Documents;1994/B:30, Working paper, 1994)
      Target strength measurements in situ of cod fry have been made using 38 and 120 kHz split beam echo sounders. Two data sets are sampled in essentially pure, evenly sized, cod concentrations, one in a Ullsfjord, Northern ...
    • Digital representation of split-beam-transducer beam patterns 

      Foote, Kenneth G. (ICES CM Documents;1986/B:2, Working paper, 1986)
      The farfield beam pattern of each of two different split-beam transducers is computed and represented in the axial region by a finite number of constant levels. The accuracy of representation is determined as a function ...
    • Directional properties of an 18-kHz transducer 

      Foote, Kenneth G. (ICES CM Documents;1993/B:29, Working paper, 1993)
      Several theoretical measures of directivity are given for an 18-kHz transducer that is used in both single-beam and split-beam applications, namely the SIMRAD transducer type 18-11 in the single-beam variant. These are ...
    • Distribution of herring (Clupea harengus) and zooplankton in the Norwegian Sea, as determined from generalised additive models 

      Olsen, Esben Moland; Melle, Webjørn; Kaartvedt, Stein; Holst, Jens Christian; Mork, Kjell Arne (ICES CM documents, Working paper, 2005)
      We analyse the variability in the distribution and feeding of the Norwegian spring-spawning herring in the period from 1995 to 2004, using survey data collected throughout the Norwegian Sea each year in May - June. The ...
    • Diurnal variation in frequency response of gadoids in the Barents Sea 

      Godø, Olav Rune; Hjellvik, Vidar; Tjøstheim, Dag (ICES CM documents, Working paper, 2006)
      Earlier studies have demonstrated substantial diurnal variation in acoustic abundance of fish. Both the level and the uncertainty of abundance estimates from surveys carried out around the clock are affected. It has been ...
    • Effect of missing modes on calibration sphere target strengths 

      Foote, Kenneth G. (ICES CM Documents;1996/B:37, Working paper, 1996)
      It has been suggested that modes of vibration of solid elastic spheres, such as those used in the calibration of echo sounder systems, can be affected by the manner of suspension. This hypothesis is investigated in the ...
    • Experiences using the ES-400, split-beam echo sounder, with special reference to the single-fish recognition criterion 

      Ona, Egil; Røttingen, Ingolf (ICES CM Documents;1986/B:38, Working paper, 1986)
      Realistic estimates of in situ target strength can be made when the fish concentrations are acoustically resolved into single individuals. In the split-beam echo sounder, as in all other systems available for in situ ...
    • Haddock avoidance reactions during trawling 

      Ona, Egil; Chruickshank, O. (ICES CM Documents;1986/B:36, Working paper, 1986)
      Fish reaction to the whole trawling operation was studied using a stationary echo sounder-system observing the fish in front of the vessel and during trawl passage. Strong avoidance reactions were observed on haddock, ...
    • 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 ...