A Transportable Acoustic Fish Census System for Lake and River Studies

The CCIW high resolution Acoustic Fish Census System is a transportable fish counting and assessment tool designed to support biological studies of fish population in Canada's inland waters. The system features an 80 kHz transducer, a transceiver with a unique precision TVG receiver, a hard-wired signal processor and data logger, a fibre optics-CRT graphic intensity display, digital data printout and digital magtape storage. The system is configured to operate from survey launches in fresh water of depths ranging from 3 to 100 m. It processes target returns in 4 echo amplitude intervals and 6 adjustable depth ranges. A bottom-tracking digital servo is incorporated to improve the security of bottom echo rejection. A brief summary of the system mathematical modelling problem is presented together with some inferred limitations on system application. Two of these systems have been constructed, and are being used by two environmental study groups.