Background
In July of 2023 the California Department of Water Resources (DWR) installed a Fish Monitoring Station (FMS) in the Low Flow Channel (LFC) of the Feather River approximately 1.5 miles upstream of the Thermalito Afterbay Outlet (see Fig.1 Project Location tab). The purpose of the FMS is to obtain accurate counts, determine temporal trends, and identify the origin of spring-run Chinook salmon, fall-run Chinook salmon, and steelhead that enter the LFC. Due to some overlap in spawn timing, previous surveys that used the traditional “carcass” survey to estimate abundance blended the in-river spawning populations of spring-run and fall-run Chinook salmon. Through operation of the FMS, DWR can accurately count and report spring-run and fall-run Chinook abundance and run timing.
No prior method was able to estimate the entire population of steelhead entering the LFC, only those entering the Feather River Fish Hatchery (FRFH). The FMS will count all adult steelhead entering the LFC.
Methods
The FMS consists of an Alaskan-style resistance board weir that funnels fish through two 12” wide x 16” tall passage chutes (Figures 2 and 3). Each chute is monitored by a primary and backup Splashcam Deep Blue Pro underwater camera. The underwater cameras are connected to a laptop computer that is running GeoVision Multicam Surveillance Software via a GeoVision GV-VS2401 video server. The primary camera uses motion detection to detect fish passing through the passage chute (Figures 4 and 5), while a backup camera records continuously. The electronic components of the FMS are powered by a 16-panel solar array.
The use of the FMS provides managers with a more precise tool to evaluate hatchery operations and determine the number and origin of salmonids using the natural spawning area in the LFC.