Understanding how altered flow regimes mediate interactions among native and nonnative species is necessary for the conservation of aquatic systems. Anthropogenic alteration of natural flows and establishment of nonnative fishes coincided with near extirpation of Colorado pikeminnow (Ptychocheilus lucius) from the San Juan River, NM, USA. Despite major efforts to re-establish this species, recruitment of young individuals into the adult population has not been documented in several decades. A potential reason for apparent recruitment failure is that modified flow regimes and nonnative species have affected reproductive success of native prey, thus limiting potentially critical resources for young (
