Dispersal and retention of fish larvae in the River Danube Project team: Hubert Keckeis, Aaron Lechner, Franz Loisl and Reinhard Krusch (University of Vienna); Helmut Habersack, Michael Tritthart, Martin Glas (BOKU University); Paul Humphries (CSU).
Fish are widely used as indicators in riverine systems for ecological integrity, as they i.a. integrate large spatial scales during their life cycle by their different use of habitats. The linkage between spawning and nursery habitats is crucial for the sustainability of fish populations, as fish larvae present critical stages in the life cycle. Dispersal patterns of larval fluvial fish are investigated on the temporal as well as spatial scale by introducing individually marked fish of different ontogenetic stage at different hydro-morphological habitats in the main river channel of the Danube.
Using an integrated habitat modelling approach the observed patterns are superimposed by particle traces derived from the application of a three-dimensional hydrodynamic model in order to define the triggers and mechanisms of larval dispersal patterns. Implications about the connectivity of spawning and nursery habitats are made based on this approach; this knowledge can be used in applied restoration ecology for large-scale restoration concepts.