Three-dimensional tracking of juvenile salmon at a mid-reach location between two dams

Abstract

Evaluating fish behavior and migration in response to environmental changes is a fundamental component of fisheries research and recovery of freshwater ecosystems. While spatial distribution and behavior of fishes has been well studied around hydropower facilities, little research has been conducted at a mid-reach location between two dams. The Juvenile Salmon Acoustic Telemetry System (JSATS) cabled receiver system was developed and employed as a reference sensor network for detecting and tracking juvenile salmon in the Columbia River Basin. To supplement acquisition of detection and three-dimensional (3-D) tracking data to estimate survival and fish behavior in the forebays of Little Goose and Lower Monumental dams on the Snake River in eastern Washington State, a mid-reach location was needed to investigate the spatial distribution of migrating juvenile salmon in open-water conditions between the two dams. Lyons Ferry Bridge on State Route 261 at the confluence of the Snake and Palouse Rivers was chosen as the mid-reach location. A JSATS-cabled receiver system configuration was successfully designed and deployed from the bridge's pier structure. Theoretical analysis confirmed the functionality and precision of the deployment design. Validation tests demonstrated sub-meter accuracy of 3-D tracking up to a horizontal distance of 50m upstream and downstream from the Lyons Ferry Bridge piers. Detection and tracking probabilities of the LFB cabled array were estimated to be 99.98% from field application. This research provided a detailed description of acoustic telemetry system deployment and 3-D tracking as guidance for better understanding of fish migration behavior as they pass through dams and continue downstream through the river between dams.