1. Department of Ichthyology; University of Warmia and Mazury in Olsztyn; Olsztyn Poland
2. Faculty of Fisheries and Protection of Waters; South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses; Research Institute of Fish Culture and Hydrobiology; University of South Bohemia in Ceske Budejovice; Vodňany Czech Republic