Zooplankton community structure and seasonal dynamics in Lake Texoma (Oklahoma-Texas)

Seventy-one species of zooplankton were identified from 16 stations within five zones in Lake Texoma (Oklahoma-Texas) over a 14-month period beginning August 1996. Whole lake mean monthly densities were greatest in mid-May (1 99.4 org/L) and least in mid-June (83.9 org/L). Mean zooplankton density wa s a third greater in the Red River arm compared to the Washita River arm an d Main Lake zone. Percent composition was similar among the five zones with rotifers making up the largest proportion followed by the nauplii, cladoce ra, cyclopoid copepods and calanoid copepods. Bray-Curtis Similarity Index at the genus level showed zooplankton community composition was most simila r between the Red River zone and Red River Transition zone, Washita River z one and Washita River Transition zone and Main Lake zone with the Main Lake zone being most similar to the Red River arm. Lake Texoma can be classifie d as eutrophic based upon the presence of rotifer and cladoceran indicator species and the ratio of calanoid to cyclopoid copepods plus cladoceran spe cies.