Christi bays which total about 5 . 4x 

 10 ha (Texas Water Development 

 Board 1968). The average rainfall 

 for this area is 76.2 cm annually. 

 This bay, historically receives ap- 

 proximately 1.23x10 m of fresh wa- 

 ter annually. Descriptive studies of 

 the Corpus Christi Bay system include 

 Hood (1952) and Anderson (1980). 



Thirty sample sites were estab- 

 lished in such a pattern as to give 

 the broadest possible coverage of the 

 different areas and physical para- 

 meters (Figure 1). Although 30 sta- 

 tions were established only four were 

 located in close proximity to major 

 sources of freshwater inflow and 

 these sites were selected to monitor 

 freshwater inflow effects on zoo- 

 plankton communities. Station 38-2 

 was located at the mouth of the Nue- 

 ces River. Station 200-2 was at the 

 entrance of Oso Bay. In Copano Bay, 

 Station 44-2 was near the mouth of 

 the Aransas River and Chiltipin 

 Creek. Station 54-3 was at the en- 

 trance of Mission Bay. 



MATERIALS AND METHODS 



Zooplankton samples were col- 

 lected with a 0.5-m #10 mesh (153 u) 

 nylon net. One-minute surface tows 

 were made in a counterclockwise di- 

 rection from the port side of the 

 boat so that the net was towed clear 

 of the boat's wake and wheelwash. 

 The amount of water filtered was mea- 

 sured with a General Oceanic Model 

 2030 digital flowmeter attached in 

 the center of the mouth of the net. 

 Samples were preserved with 5 percent 

 buffered Formalin. 



In the laboratory, plankton sam- 

 ples were subsampled using a Hensen- 

 Stemple pipette. Counts were made 



using a Wild M-5 dissecting micro- 

 scope. Standing crops were express- 

 ed as total numbers of individuals 

 per cubic meter (m ) . 



Local rainfall data, which were 

 collected at the Corpus Christi In- 

 ternational Airport were obtained 

 from summaries of annual rainfall for 

 this area (United States Department 

 of Commerce 1972, 1973, 1974, 1975). 

 Total inches of rainfall for the 10- 

 day period prior to and including the 

 collecting date, were used for linear 

 correlations with salinity data. 



Streamflow data were obtained 

 from the Texas Natural Resources In- 

 formation System in Austin, Texas for 

 the following gaging stations :0821- 

 1000, Nueces River near Mathis, Tex- 

 as; 08211520, Oso Creek at Corpus 

 Christi, Texas; 08189700, Aransas 

 River near Skidmore, Texas; 08189- 

 800, Chiltipin Creek at Sinton, Tex- 

 as; and 08189500, Mission River at 

 Refugio, Texas. These were the most 

 downstream gaging stations nearest 

 the sampling sites. Streamflow was 

 measured in cubic feet/second (cfs). 

 Total inflow for a 10-day period, 

 prior to and including the date of 

 data collection, were used for linear 

 correlations. All linear correla- 

 tions between streamflow and zoo- 

 plankton standing crops were calcu- 

 lated using raw data. The critical 

 level for rejection of signifi- 

 cance for a linear correlation was 

 p = 0.05. 



Water temperature, dissolved ox- 

 ygen, conductivity, and salinity were 

 measured at each station. Salinity 

 was the only hydrographic data used 

 for analysis in this presentation. 



RESULTS 



The highest recorded rainfall 

 from October 1972 to May 1975 for 



455 



