How many fish pass through the dams on Missouri River reservoirs and survive?
It is unknown how many fish pass through Missouri River dams but passage of fish from one lake to another continuously occurs. The primary species passing through Oahe Dam are rainbow smelt, lake herring, rainbow trout, and Chinook salmon. High reservoir releases during 1997, due to high water inflows, caused 36% of tagged walleye in Lake Francis Case to pass over the spillway of Fort Randall Dam into Lake Lewis and Clark. Passage of cold-water fish through Oahe Dam was also substantial during 1997. While many fish do survive, large numbers also die due to changes in pressure and temperature and from hitting turbine blades as they pass through.
