Some nonnative fishes have exhibited different feeding behaviors depending on location. In a study within the Colorado River system, Ruppert et al. (1993) found a relatively high occurrence (15%) of larval fish in stomachs of Cyprinella lutrensis. They compared those results to a study by Jennings and Saiki (1990) who found no larval fish in stomachs of C. lutrensis from the San Joaquin River drainage. The disparity between these studies could be a function of site specific characteristics such as availability of alternative food items, or it could be due to specific behavior and vulnerability of prey. The purpose of our study was to determine if nonnative fishes, primarily C. lutrensis and Pimephales promelas, prey on larvae of native [...]
