Species composition, abundance and distribution of macro-crustaceans and fishes in the intake area, discharge canal, and cooling lake of the Cedar Bayou electric generating station, near Baytown, Texas

Abstract

Species composition, abundance, and distribution of macro-crustaceans and fishes in the intake area, discharge canal and cooling lake of the Cedar Bayou Electric Generating Station near Baytown, Texas, were analyzed using data collected by trawling, trammeling, and seining from November 1973 through September 1975. Hydrological data were taken prior to each collection. The data were compared with those of previous studies. Anaerobic conditions and extreme conductivity due to sewage and brine pollution downstream of the plant was eliminated by the reversed flow in Cedar Bayou. This increased the number of species caught in the intake area; there were 61 species collected during September 1974 through September 1975 with three units in operation but only 45 during more than 4 years of previous study with none to two units in operation. In general, the mean CPUE (catch-per-unit-of-effort) of migratory species increased soon after the plant began operation but eventually levelled off. On the other hand the mean CPUE of resident species decreased soon after start-up but later increased again. For migratory species, population changes in the cooling lake were more closely related to those in the intake area than for resident species. The changes were modified by varied survival rate during transit to and ecological conditions in the cooling lake. The decay of the inundated marsh grass and the absence of phanerogams in the cooling lake were limited factors for marsh species, animals which use vegetation as a spawning site, and for those whose young use it as a cover.