Volume scattering strengths and zooplankton distributions at acoustic frequencies between 0.5 and 3 MHz

Measurements of ultra-high-frequency acoustic volume scattering strengths in California current waters revealed a complex structure of thin scattering layers in the upper 100 m. These scattering strength profiles are illustrated along with size distributions of zooplankton collected at the same time and depth as the acoustic measurements. Within the uncertainties in the biological measurements and the assumed physical properties of the animals collected, the principal features of the acoustic profiles can be explained by the zooplankton distributions.