A General Guide for Deriving Abundance Estimates from Hydroacoustic Data





Acoustic Background

This section provides general background information on concepts relevant to fisheries acoustic surveys.  Additional information may be found in acoustic texts such as Simmonds and MacLennan (2005).  An introduction to acoustics is in Brandt (1996) and Rudstam et al. (in press).

Acoustic theory and use

  • Definitions, symbols and units
  • The SONAR equation

  • Introduction
  • General equation
  • Beam width or 3dB angle
  • The equivalent beam angle
  • Volume backscattering
  • Acoustic transducers

  • Beam pattern
  • Near-field and far-field
  • Target stength

    Volume backscattering

    Detection probability

    Signal-to-noise ratio

    Vessel noise and avoidance

    Near surface and near bottom dead zones