Ochrana a obnova migrační prostupnosti vodních toků pro vodní organismy-rybí přechody na dolní Ohři (Terezín, Doksany, Hostenice)

Abstract

In the period from May till December 2004 and from April till November 2009 - 2010 three fish ladders were monitored on the Ohře River in hydraulic structures Terezín, Doksany and Hostěnice. As a case study the fish ladder located in the Terezín hydraulic structure was chosen. In the exemplary fish ladder in Terezín the influence of external conditions to the process of migration of objective fish species was analysed. At the same time the efficacy of its structure for fish migration was tested.

For the data collection a direct fishing of fish species was used from fish ladders and from the river with the use of power unit (the downstream section of the fish ladder). The fish ladders were tested for their size and specific selektivity. At the same time the influence of extensive factors was monitored affecting the process of migration like a stream flow, temperature of water and light. For a data evaluation of the fish migration in the Terezín exemplary fish ladder, 1097 pieces from 12 species of carp fish were used in the fish ladder and 48 pieces from 8 species of carp fish were used in the downstream river section. For the analysis of the migratory behaviour of the Ohře river's ichtyofauna were used 1133 pieces from 16 fish species in the fish ladders and 51 pieces from 10 species in the downstream river sections.