The occurence of larval and juvenile 0+ fish in the Lower River Rhine
Staas, S.; Neumann, D.
In 1992 and 1993 the reproduction of fish was studied in two downstream reaches of the Lower River Rhine and neighbouring gravel-pit lakes connected to the river. Sampling of fish aged 0+ in the littoral zones was done with a fine-meshed beach-seine net on numerous occasions from springtime throughout to the autumn. Different biotope-types were defined and the characteristics of their 0+ fish communities were analysed. Although successful reproduction of 17 species forming relatively large stocks was recorded in the Lower River Rhine, only a few ubiquitous species showed high abundances and regular occurrence in different types of biotopes. River engineering works along the banks restrict the formation of valuable nursery habitats of fish, especially of rheophilic species. The gravel-pit lakes connected to the river are valuable spawning and nursery areas for flow-indifferent cyprinids and perches.