A novel Doppler based speed measurement technique for individual free-ranging fish

A novel Doppler based speed measurement technique for free-ranging acoustically tagged fish was developed and validated through a field experiment in a marine aquaculture farm. For emulated swimming speeds in the range 25cm/s-60cm/s, an rms error of 5cm/s with a standard deviation of 4.7cm/s was achieved, and with a relative error typically less than 10% of measured speed. The technique is designed to integrate easily with existing acoustic fish telemetry systems and requires only three hydrophones to determine swimming speeds. Measurement of fish swimming speed has a wide range of applications within fisheries sciences and may become a valuable tool for assessing fish behavior and performance in marine farms