An Experimental Approach for the Quantitative Assessment of Downstream
Swimming Fish Behavior
Abstract
The RETERO project develops new methods to Reduce, Replace and Refine
(3R-principle) animal experiments for assessing the risk of harm to fish
when passing through turbines or pumps. Since behavior of fish
influences the mortality risk during turbine and pump passages,
knowledge about species-specific behavior and its triggers are
necessary. A primary objective of the RETERO project is the study of
fish behavior in hydraulic conditions similar to turbine and pump
intakes. Therefore, an experimental conduit was constructed at the
Hubert-Engels Laboratory of Technische Universität Dresden (Germany)
specifically for the RETERO project’s study on fish behavior, equipped
with a 3D camera infrared tracking system. The conduit was designed to
model hydraulic conditions typical for turbine and pump intakes. In the
experimental setup the effects of flow velocities exceeding the maximum
swim speed of fish, as well as spatial velocity gradients and
illumination conditions, on the fish behavior are studied. The data from
studies involving brown trout ( Salmo trutta) allow for an
analysis of how these fish react to flow accelerations and velocities
surpassing their sprint speed, using quantitative metrics for movement
and activity. An initial evaluation of these experiments highlights the
potential of this approach for further research.