Response relationships between juvenile salmon and an autonomous sensor in turbulent flow

Abstract

Juvenile fall Chinook salmon ( Oncorhynchus tshawythscha) and an autonomous sensor device (Sensor Fish) were exposed to turbulent shear flows to determine how hydraulic conditions affected fish injury response. Studies were designed to establish correlation metrics between Sensor Fish device measurements and live fish injuries by conducting concurrent releases in a range of turbulent shear flows. Comparisons were made for two exposure scenarios. In the fast-fish-to-slow-water scenario, test fish were carried by the fast-moving water of a submerged turbulent jet into the standing water of a flume. In the slow-fish-to-fast-water scenario, test fish were introduced into a turbulent jet from standing water through an introduction tube placed just outside the edge of the jet. Motion-tracking analysis was performed on high-speed, high-resolution digital videos of all the releases at water jet velocities ranging from 3 to 22.9 m s −1. Velocities of the Sensor Fish were very similar to those of live fish, but maximum accelerations of live fish were larger than those of Sensor Fish for all the nozzle velocities of both scenarios. A 10% probability of major injury threshold was found to occur at Sensor Fish accelerations of 513 and 260 m s −2 for the fast-fish-to-slow-water and slow-fish-to-fast-water scenarios, respectively. The findings provide a linkage between laboratory experiments of fish injury, field survival studies, and numerical modeling.