Diets of young Colorado squawfish and other small fish in backwaters of the Green River, Colorado and Utah
ABSTRACT.-We compared diet of young-or-year Colorado squawfish (Ptychocheilus lucius), an endangered cyprinid, with diets of other fish <75 mm total length (TL) collected from backwaters of the Green River between river kilometers 555 and 35 during summer and autumn 1987. Species included native Rhinichthys osculus, Catostomus discoholus, and C. latipinnis, and nonnative Cyprinella lutrensis, Notrupis stramineus, Pit"l1&'Phales promelas, Ictalurus punctatus, and upamis cyanelll1s. For (;,-8.ch species, diet varied with size and between upper and lower river reaches but not between seasons for Hsh of similar size. Larval chironomids and ccratopogonids were principal foods of most fishes. Copepods and cladocerans...