The investigated fish were fin-clipped and the clips stored in 70% ethanol for molecular analyses. The molecular identification of hybrids was performed using partial mtDNA representing the hypervariable part of the control region (D-loop) following Papoušek et al. (2008) and five microsatellite loci GF29, MFW2, MFW7, J1 and J62 following Papoušek et al. (2008) and Yue and Orban (2002).
Animal care was in accordance with Law No. 207/2004 of the collections of Laws of the Czech Republic on the protection, breeding and use of experimental animals. This study was performed following project of experiments n. 031/2011 approved by animal care and use committee in Faculty of Science, Masaryk University in Brno (Czech Republic).