Abstract
The stranding of juvenile coho salmon Oncorhynchus kisutch and rainbow trout O. mykiss on river bars caused by rapid decreases in river flow during the operation of hydroelectric facilities was investigated in an artificial stream channel. We conducted experiments with winter water temperatures (<4°C) and a gravel substrate, In daytime trials, many fish became stranded because they were concealed in the interstitial areas of the substrate and were reluctant to leave when water levels receded. Coho salmon were more likely to be stranded than rainbow trout. At night, instead of using the substrate as cover, fish were active in the water column and the incidence of stranding during flow reductions was greatly diminished. Stranding was less frequent at slow rates of dewatering. The addition of shallow, covered pools to the substrate did not alter the principal results. Our findings suggest that during winter months, fish losses from stranding will be minimized if flow reductions occur at night and at slow rates of change.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call