University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Jürgen Kern
(2013):
Technische und fischökologische Funktionsprüfung des enature® Fischpasses am Wehr Hart/Ager OÖ.
Master / Diploma Thesis - Institut für Wasserwirtschaft, Hydrologie und konstruktiver Wasserbau (IWHW),
BOKU-Universität für Bodenkultur,
pp 203.
UB BOKU
obvsg
FullText
- Abstract:
- The functional capability of a pilot plant of the enature® Fishpass, at the weir Hart / Ager was assessed by the use of fish-ecological and technical analyses. For the evaluation of operational reliability, the possibility for fish to find the entrance and to pass the fishway, abiotic parameters were collected. The measurements of flow velocity in the tailwater show a good orientation of the main flow. However, there was no separate flow observed, qualified to attract fish into the fishpass, even though the discharge of the fishpass was higher than recommended. The maximum measured flow velocities at all checked multistructure slots were below the design value. The smallest determined flow velocities exceeded the critical swimming capacity of small and juvenile fish. In contrast to this, the fish-ecological investigation gave a different picture. To determine fish migration fish traps were installed in the fishpass. In 21weeks of monitoring 1 226 ascending fish were caught. It became apparent that all species observed in the tailwater were able to find and swim through the pass. The most represented fish were small individuals and bad swimmers. According to guideline of the Austrian Fishing Association (ÖFV 1/2003) the enature® Fishpass was assessed as „fully working, mark I“. In the course of video monitoring the fishway was observed as passable for a Danube salmon (Hucho hucho) with a length of 105cm. The fish coped easily with movements both up and downstream. In consideration of the partly contradictory biotic and abiotic results, the importance of fish-ecological monitoring becomes apparent. Furthermore there is still a lack of research regarding the mechanisms of how fish find the entrance of a fishpass. Differing from the common theory of the “attraction flow” it can be assumed that there are other factors that provide the necessary information for fish to orientate. In summary the functional capability of the enature® Fishpass can be evaluated as very high.
- Beurteilende(r): Mader Helmut
- 1.Mitwirkender: Schmutz Stefan