Species composition, distribution, and seasonal abundance of macro-zooplankton in intake and discharge areas before and during early operation of the Cedar Bayou generating station.

The species composition, distribution, and abundance of macro-zooplankton in the intake and discharge areas of Houston Lighting and Power Company's new Cedar Bayou Generating Station were investigated during the period of October 16, 1969 through December 17, 1970. All plankton samples were made with a 0.5 meter (diameter of mouth of net) plankton net made of 0.5 mm mesh nylon netting. Generation of electric power and discharge of heated water by Unit 1, a 750 MW steam-electric unit began on November 5, 1970. Intake water from Tabbs Bay and Cedar Bayou was discharged into Trinity Bay. The greatest abundance of species for both invertebrates and vertebrates combined was the Discharge Area followed by Tabbs Bay, Cedar Bayou, and Middle Bay. Mean catch values for all animals (invertebrates and vertebrates combined) were highest in Tabbs Bay followed by the Discharge Area, Middle Bay and Cedar Bayou. Mean catch values for invertebrates was highest in Tabbs Bay. Possible causal factors include: (1) degree of pollution in each area, (2) amount of available nutrient material in each area, and (3) physical differences in the areas themselves.