Hydroacoustic surveys were conducted on Cultus Lake in British Columbia and Lake Oahe in South Dakota in July, 1983. Dual-beam and echo integration techniques were employed. Estimates of pelagic fish abundance were obtained at Cultus Lake compared well with those obtained from mid-water trawl samples. Acoustic target strength data collected at Lake Oahe indicated a bimodal size distribution of fish; mid-water trawl samples indicated that this distribution was due to the presence of adult and juvenile rainbow smelt.