Processes and Patterns of Larval Fish Drift in Rivers: A Review
1Aaron Lechner, 1Hubert Keckeis & 2Paul Humphries
1University of Vienna, Department of Limnology and Oceanography, Faculty of Life Sciences, Althanstrasse 14, 1090 Vienna, Austria.
2School of Environmental Sciences, Charles Sturt University, PO Box 789, Albury, NSW 2640, Australia
The current-mediated dispersal (drift) of young during the embryonic and larval periods is an integral part in the life cycle of many riverine species. It enhances habitat connectivity and gene flow, promotes community stability and serves to extend the range of populations; thus drift is linked to ecological and evolutionary functions. Knowledge about dispersal modes and requirements of fish larvae in rivers is critical for river conservation, management and restoration. Although studies of the drift of fish larvae in lotic waters are common, a review of current understanding and knowledge gaps does not exist.. Here, we review: a) patterns of drift among taxa and larval stages b) the mechanisms and patterns of drift entrance, transport and drift exit; and c) the mode of drift (passive, active or active/passive). These patterns are discussed with regard to hydrodynamic characteristics and to abiotic conditions of the river systems (river type, flow-pattern and biogegraphy).