Spawning and niche shift of some threatened riverine fishes of Europe
The protection of riverine systems and their biodiversity depends on a solid knowledge of the species concerned. Important ideas were presented by Balon (1964, 1975, 1981) and Holcík et al. (1989) with their classification of the European freshwater fishes. An update of this system now appears to be necessary. Minnow (Phoxinus phoxinus), spirlin (Alburnoides bipunctatus), vimba (Vimba vimba), soufie (Leuciscus souffia) and stone gudgeon (Gobio uranoscopus) were tested in the laboratory with respect of their reproductive strategy. The spawning habitat of the minnow, spirlin, vimba and soufie is characterized by gravel of specific diameters and/or specific stream velocities. Eggs are positioned precisely deep into the interstices of the spawning ground. Spawning of the stone gudgeon takes place in the free-flowing water. Eggs are drifted by water current and adhere to any substrata provided. The results do not fully support the above-mentioned classification.