Using Turbulence to Identify Preferential Areas for Grass Carp ( <i>Ctenopharyngodon idella</i> ) Larvae in Streams: A Laboratory Study

In this experimental series, we studied the swimming capabilities and response of grass carp (Ctenopharyngodon idella) larvae to flow turbulence in a laboratory flume. We compared three different configurations, representing in-stream obstructions commonly found natural streams (e.g., gravel bump, single vertical cylinder, patches submerged rigid vegetation). Grass (postgas bladder emergence) were introduced each configuration subjected variety hydrodynamic forces magnitudes scales. varied velocities water depths ranges turbulent kinetic energy Reynolds stresses that triggered larval trajectories, identified by measured horizontal speeds for condition. Larvae apparently actively avoided areas with increased levels away, moving faster short bursts, expending more energy. addition magnitude energy, length scale time eddies also influenced response. These findings support development new strategies controlling spread rivers, as well numerical tools incorporating active predict transport streams.