Fish Injury and Mortality caused by Simulated Impacts from Turbine Blades

Riverine fishes impacted by hydroelectric dams often pass through hydropower turbines during annual downstream migrations. During turbine passage, fish may experience a suite of stressors including rapid pressure changes, exposure to hydraulic shear, and impacts from turbine blades or collisions with stationary structures. To better understand the effects of blade strike impact on rates of fish injury and mortality, we conducted controlled experiments on nine species of riverine fishes. Two main treatment effects were investigated relative to 1) aspects of the turbine blade and 2) changes relative to where the strike impacted the fish itself. Blade impact velocity (meters per second) ranged from 4.7 to 13.6 and blade leading edge thicknesses of 19, 26, 52, or 76 millimeters were also used in these experiments. Impacts with the fish could vary by location (head, mid-body, or tail), orientation (dorsal, lateral, or ventral surfaces), and angle of strike (45, 90, or 135°). Exact treatment conditions varied by groups of 20 to 25 individuals and also included 3 to 5 control fish. Anesthetized fish (including controls) were placed in the simulated blade strike apparatus, struck (if a treatment fish), tagged for identification, and were observed for one-hour post-strike to assess survival. Following observation, all fish were euthanized to perform detailed external and internal examinations for injuries. Other characteristics of the fish reported in these data are standard or total length (centimeters), wet mass (grams), and sex (for some species). Simulated impact testing was successfully performed on more than 2500 individual fish nine species (gizzard shad, rainbow trout, hybrid striped bass, bluegill sunfish, American eel, American paddlefish, brook trout, American shad, and blueback herring) over a five-year period. In general, these data have confirmed impacts may be severely injurious and cause direct mortality if riverine fishes are exposed to strikes from hydropower turbine blades.