Fish abundance, distribution, and species composition was determined in the intake(Tabbs Bay and Cedar Bayou) and discharge (Trinity Bay) areas before and after operation of the first 750 Mw unit of the Cedar Bayou Electric Power Station, Chambers County, Texas. The initial months of plant operations were erratic. There were no operations during May 24-June3 and July 7 - September 10, 1971, periods when maximum stress would be imposed on fishes by thermal effluent due to high, naturally -occuring temperatures. Otter trawls, bag seines, trammel nets and pushnet were used in sampling.