Fish Stock Survey in Johnsbach — Postmonitoring

The Institute of Hydrobiology and Water Management of the BOKU was commissioned to carry out the fish ecological monitoring in Johnsbach as part of the EU Life project. Fish Ecological Postmonitoring took place in September 2009. Since fish passability was not guaranteed at the time of post-monitoring, a master thesis was awarded in addition to the existing order with a focus on the analysis of the fish passability of converted solitudes.

Since the entry into force of the EU Water Framework Directive (WFD) in December 2000, there are new legal frameworks for ecologically oriented water management. The WFD is to be implemented in the respective national legislation and sets the good ecological status for the Member States as a binding target (until 2016). The current state, in addition to chemical and physical components, is determined by the composition of the biocenosis of the waters. Therefore, fish deposits in species and individuals also play an important role in this respect. If these deviate from the (original) water type-specific state, it is necessary to examine in what form (e.g. in terms of quality, morphology, hydrology, continuum) action is required and with which measures it can be adapted.

The Institute of Hydrobiology and Water Management (Department for Water Atmosphere Environment) of the University of Natural Resources Vienna was commissioned to carry out the fish ecological monitoring in Johnsbach as part of the EU Life project Nature Conservation Strategies for Forest and Wild River in the Gesäuse (LIFE05NAT/A/78) a right-wing feeder of the Enns in the Gesäuse National Park. In addition to post-monitoring (state after implementation of measures), a comparison to premonitoring (Wiesner et al. 2006) The LIFE project included, among other things, the restoration of the water continuum in the Johnsbach from the Enns to the Silberreith (Zwischmäuerstrecke, NATURA 2000 area) by rebuilding or dissolving several hollow steps. This life project was carried out from 2005 to 2009 in cooperation with Nationalpark Gesäuse GmbH with the Styrian State Government, Policy Department 19B and the Forest Technical Service for Wildbach and Avalanche Construction. The funding is provided by the above-mentioned bodies and from the EC and LIFE Nature Programmes.

Fish ecological premonitoring took place from 17 to 18 November 2005, post-monitoring from 16 to 17 September 2009. Since fish passability was not guaranteed at the time of post-monitoring, a master thesis was awarded, in addition to the existing contract, with a focus on the analysis of fish passability of converted solitudes (Kammerhofer 2010). The necessary measurements were carried out on 14, 15 and 18 September 2009 and from 20 to 23 and 31 December 2009. It was held in December 2009.