Structure of fish communities of five small water reservoirs located near the Wieprz--Krzna Canal was investigated during the years 2002, 2008 and 2014. In the analyzed water bod-ies seven fish were noted, representing four families: Cyprinidae (5 species) and Esocidae, Cobi-tidae and Ictaluridae (1 species each). In the structure of collected fish two protected species (M. fossilis and R. sericeus amarus) and one alien species (C. auratus gibelio) were presented. Domination structure of ichthyofauna showed considerable differences. Among the dominant species were: I. nebulosus (all five reservoir), C. auratus (Jabłoń Center 2, Jabłoń Church and Jabłoń Firlej-Ostrówek), and R. rutilus (Jabłoń West and Jabłoń Firlej-Ostrówek). The percentage of each fish species in the biomass was slightly different in relation to the structure of domination expressed by the number of identified individuals. Regardless of the reservoir, larger share held: E. lucius, I. nebulosus and C. auratus Moreover, one of the purpose of the study was searching for a new stands of lake minnow. However, the species was not recorded in fish communities of any of the reservoirs, despite of the ecological state of reservoirs indicating the potential habitat for lake minnow.
In December 1939 the Deputy Führer Rudolf Hess performed the ground-breaking ceremony for the Oder-Danube Canal, with Austria, Poland and the Protectorate of Bohemia and Moravia already under German control,. Besides connecting the Oder and the Danube, resulting in a nonstop waterway from the Baltic Sea to the Black Sea, spatial planning authorities, he saw the canal as a fundamental addition for the ‘second Ruhr valley in the East’ (Upper Silesia). The outcome of this connection would have been a widely expanded trade between northern and southern Europe. The trade might become then faster and cheaper, a wide array of strategic materials like coal, ore, petroleum and petrol would have been accessible for industry and armed forces. Due to the war progress the work on the canal had to be discontinued in 1940. One of the profiteers of the canal should have been the seaport in Szczecin, located at the intersection of the Oder and the Baltic Sea. Therefore a think tank called the ‘Oder-Donau-Institut’ has been found to deliver scientific arguments reinstating the work on the canal under the lead management of the economic chamber of Pomerania (Szczecin) in close contact with the University of Greifswald. The director of the institute was Heinz Seraphim, professor for political economy at the University of Greifswald. Under his leadership, the well-financed institute started to work not only for the economic interests of the economic chamber but also for the SS-Reichssicherheitshauptamt.