Effects of hydrological and biological variables on the survival, growth, and food utilization of estuarine fishes cage-cultured in a heated water system

Abstract

Estuarine fishes were cultured in cages in the intake area and at four locations in the cooling lake of a power plant near Baytown, Texas from 1 September 1976 through 1 September 1978 to determine the effects of heated water on the dynamics of growth. Evaluation of data was based on eight hydrological variables, survival, growth and food-conversion efficiency of pinfish (Lagodon rbomboides) , spot (Lelostomus xanthuzus) , Atlantic croaker (Micropogonias xmdulatus), black drum (Pogonias czomis) and striped mullet (Mugil cephalus). The heated-water system was typified by high variability (rapid drops in salinity; maximum 20.4 to 0 pot) in the intake area which decreased as water was mixed during passage through the cooling lafee- Temperature averaged 11.1 C higher in the discharge canal than in the intake area, but was only 1-2 C higher in water discharged into Trinity 3ay. Salinity and turbidity fluctuated greatly in the intake area as a function of rainfall rate, but progressively less variation occurred as water passed through the cooling lake. Dissolved oxygen concentration (DO) was inversely related to temperature. Daily pH fluctuated more during the winter when rainfall was great than in the summer when rainfall was less. Supersaturation of gas in the water reached detrimental levels only in the discharge canal.