  The use of quantitative broadband echosounders for biological studies and
surveys offers considerable advantages over narrowband echosounders. These
include improved spectral-based target identification and significantly
increased ability to resolve individual targets. Biological studies and surveys
typically require accurate measures of backscatter strength and we present here
a systematic and comprehensive explanation of how to derive quantitative
estimates of target strength and volume backscattering, as a function of
frequency from broadband echosounder signals.
