Fish regions

The fish regions are a longitudinal division of rivers based on the sequence of typical cönoses (living communities). The fish habitat is divided into the following biocenotic regions: Epirhithral (upper trout region), metarhithral (lower trout region), hyporhithral (ash region), epipotamal (barb region) and metapotamal (breathing region). In the national assessment scheme currently applied, the waters of the hyporhithral (ash region) and the epipotamal (barb region) were broken down into two and three regions according to the flow and width of the water. The fish regions and the fish guides assigned to them in combination with the river bioregion provide the water-type reference status for fish fauna. The state of data shall be in line with the 2015 National Water Management Plan (NMP) and shall be updated as appropriate after the publication of the NGP 2021.