Suitability of Food Resources and Physicochemical Parameters in the Lower Trinity River, Texas for Paddlefish

We examined the zooplankton community and physicochemical parameters of the lower Trinity River, Texas during March 1992-March 1993, and evaluated the suitability of each for survival of paddlefish Polyodon spathula. Samples were collected every 2–4 weeks from mid-river channel and backwater stations at each of four sites. Eight paddlefish stomachs were analyzed, and eighteen paddlefish were aged and their relative weight values were determined. Physicochemical parameters generally were suitable for paddlefish survival. Zooplankton densities were low (overall mean 30.1 organisms/L) but similar to other river systems supporting paddlefish. The zooplankton community was dominated by rotifers; cladocerans and copepods were not abundant. Paddlefish stomach analysis indicated rotifers were being consumed by paddlefish. Paddlefish growth appeared to be rapid despite seemingly low food densities.