Can velocity affect growth and fecundity of facultative riverine fish species?

The length and body weight at subsequent annuli of four facultative riverine fish species: roach (Rutilus rutilus L.), perch (Perca fluviatilis L.), bream (Abramis brama L.) and pike (Esox lucius L.) living in lakes and rivers were compared on the basis of published data. Pike grew better in lakes (significant differences in length, and some for weight), but the other species in rivers. However, significant differences between medians were observed in all cases only for body length of roach, in many cases for the length of bream, as well as a few for its weight, and no one for perch. Comparable data on relative fecundity in both habitats were available for roach and pike. Pike females produced more eggs in lakes, but roach – in rivers, and the differences were significant.