STUDIES ON ACOUSTIC ESTIMATION OF FISH POPULATIONS IN LAKE DONG-HU

Fish populations in Lake Dong-hu, Wuhan, China, were estimated by using the echo sounder for shallow lakes.The transducer was set vertically or horizontally to receive the fish echoes from all water layers.It was recognized that there were differences between fish densities in lake-divisions according to the results of time series analysis and two-way analysis of variance for the number of echo traces on 100 m unit distances, fish densities in the searching volumes calculated with the main beam angle of an echo.Fish populations estimated were discussed in connection with catch, numbers of fish stocked and fish distribution in the lake.