The objectives of this study were: (1) determination of the identity of any planktonic rotifers occurring anywhere within the Ocqueoc River system; (2) comparison of the qualitative and quantitative aspects of the separate rotifer faunas in each of the discrete lotic and lentic habitats of the system; (3) analysis of the differential effects of stream and impoundment conditions, natural or otherwise, on both autochthonous (produced within a given area) and allochthonous (produced outside a given area) rotiferan faunas; and (4) determination of those factors, whether physical, chemical, biological or any combination thereof, which in any significant degree might be responsible for the development and maintenance of any autochthonous rotifer fauna anywhere in the system.