The effects on selected organisms of water passing through the Cedar Bayou generating station
The quality of water passing through the Cedar Bayou Generating Station was monitored during 1977 by observing the growth and survival of fishes and crustaceans in ponds and aquaria receiving water from the discharge canal, and by maintaining fish in cages in the intake, discharge canal, and cooling lake. In addition, a regular program of sampling fishes, crustaceans, and phytoplankton in Cedar Bayou, the discharge canal, and the cooling lake was carried out. Losses of fish held in cages were attributable to escapes, handling stress, gas bubble disease, salinity fluctuations, low winter temperatures, and low dissolved oxygen levels due to cage fouling. High summer temperatures in the discharge canal were also a cause of mortalities among caged fish held in that area. Most mortalities in the aquaria were due to disease, low salinities, handling stress, high temperatures, territorial aggression, jumping out of the aquaria, and low dissolved oxygen levels. Mortalities among pond-held fish were mainly due to handling stress, low salinities, and low winter temperatures. No significant mortalities occurred among pond-held shrimp. Phytoplankton studies have found that mean chlorophyll a concentrations and mean primary productivity rates at stations within the cooling system and stations in Trinity Bay were not significantly different. Differences in species composition between Cedar Bayou, discharge canal, and cooling lake were disclosed by the cooling lake study. Analyses for pesticides and heavy metals of shrimp and fish held in the ponds and cages indicated that amounts of these substances were generally much less than maximum permissable levels. In general, the water passing through the Cedar Bayou Generating Station in 1977 was not detrimental to the animals used in this study.