The critical water velocities of larval roach (Rutilus rutilus) and dace (Leuciscus leuciscus) and implications for river management

Results from artificial flow channels showed that the ability of 0 group roach (Rutilus rutilus) and dace (Leuciscus leuciscus) to hold station was positively related to fish length and water temperature, and negatively related to water velocity. Interspecific differences in hatching times and 0 group ontogeny mean that a range of microhabitats are required to support a mixed species community. Optimum recruitment of 0 group fish will occur only if river management protocols provide such habitat diversity, especially within the riparian zone.