2019_programme: THE EFFECT OF ATTENUATION FROM MULTIPLE FORWARD SCATTERING THROUGH FISH SHOALS ON ECOSYSTEM SCALE ACOUSTIC SENSING

• Session: 03. Acoustic Monitoring of Ocean Environments and Processes: Biology, Ecology, Geophysics and Man-made activities
  Organiser(s): Ratilal Purnima, Miksis-Olds Jennifer
• Lecture: THE EFFECT OF ATTENUATION FROM MULTIPLE FORWARD SCATTERING THROUGH FISH SHOALS ON ECOSYSTEM SCALE ACOUSTIC SENSING
  Paper ID: 758
  Author(s): Duane Daniel, Cho Byunggu, Jain Ankita, Godø Olav Rune, Makris Nicholas
  Presenter: Duane Daniel
  Presentation type: oral
  Abstract: Acoustic waves traveling through a group of fish experience attenuation from multiple forward scattering that increases with number density and swimbladder target strength. Here, we study the effects of attenuation on long-range sensing of vast fish shoals in an ocean waveguide. Measured attenuation is shown to be in agreement with an analytical model derived from first principles for acoustic propagation through inhomogeneities in an ocean waveguide, and consistency is demonstrated between concurrently measured backscattered returns and attenuation from multiple forward scattering. No significant attenuation was observed in previous ocean acoustic waveguide remote sensing (OAWRS) experiments because the sensing frequency was sufficiently far from the swimbladder resonance peak of the shoaling fish. Here we show experimentally and theoretically that attenuation can be significant when the sensing frequency is near the resonance frequency of the shoaling fish.
• Corresponding author: Mr Duane Daniel
  Affiliation: MIT
  Country: United States
  e-mail: