Spatial resource utilization and species assemblages of larval and juvenile fishes
The ecological requirements of larval fish species were investigated in the free-flowing section of the Austrian Danube. Species-specific demands on structural properties of riparian biotops are crucial to survival, habitat utilization and distribution patterns of riverine fish fry during early ontogenetic development. A total of 32 407 individuals of O+ fish were collected between 1986 and 1990. Altogether 26 out of 60 species known from this region were detected, dominated by cyprinids. Abundance, species richness and diversity were examined and related to the type of environment. Distinct interspecific habitat use was identified by factorial analyses. The distribution of species among habitats showed that current velocity and substrate patterns were the most important gradients. Differences in shoreline structure are correlated with spatial variability in species diversity.