Modelling the dispersal of riverine fish larvae: from a raster-based analysis of movement patterns within a racetrack flume to a rheoreaction-based correlated random walk (RCRW) model approach

Recruitment of Chondrostoma nasus (Linnaeus 1758) and similar fish species in rivers is related to spatio-temporal linkages between larval hatching and nursery habitats. Active swimming behaviour contradicts the assumption that passive particle tracing models can serve as a proxy for larval dispersal models. A racetrack flume with an inshore area of near-natural slope was created to observe individual larval trajectories. A new three-step, raster-based analysis was developed to distinguish four types of movement patterns: active upstream, active downstream, active-passive and passive. Both larval developmental stage- and release site-specific occurrences of these movement patterns were experimentally found for nine flow velocity classes (â ¤0.225 m s-1). These current-induced movement patterns, and evaluated durations within them, were used to develop a biased and correlated random walk (BCRW) model which includes rheoreactionâ a key behavioural response of fish to flow within rivers. The study introduces the concept and application of a rheoreaction-based correlated random walk (RCRW) model which, coupled with a 3D hydrodynamic model, allows prediction of the spatio-temporal effects of various river discharges, morphologies and restoration scenarios on larval fish dispersal.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author