Differences in spatial communities of European perch ( Perca fluviatilis Linnaeus, 1758) fry in a canyon-shaped reservoir are not attributable to genetics.

The question was whether a canyon-shaped reservoir is inhabited by genetically distinct populations of European perch Perca fluviatilis exhibiting different spatial behaviour, or by a single population. The study was conducted in the spring of 2006 at Římov Reservoir, Czech Republic. Epipelagic and bathypelagic perch fry ( EPF and BPF) were captured by trawl net (mesh size 1 × 1.35 mm) controlled by echo sounder, and littoral perch fry and adults ( LPF and LPA) were caught by electrofishing and beach seine (mesh size 1 × 1.35 mm). DNA was isolated in 266 individuals from the reservoir, and phylogenetic analysis based on mt DNA was performed ( n = 18) on BPF, EPF, LPF, and LPA from the reservoir and additional sequences from Central Europe. Six microsatellites were used for differentiating among communities ( n = 266). There was no evidence for genetic divergence in mt DNA sequences. Analyses of microsatellites revealed no statistically significant variations between spatial communities, and confirmed genetic homogeneity among communities. F_ST values and the number of genetic clusters point to the same conclusion, i.e., the reservoir is inhabited by a single population whose individuals occupy different microhabitats. [ABSTRACT FROM AUTHOR]