Above the John Day, Bonneville and The Dalles dams the population was estimated to be only 50,000 in each reservoir. However that is an improvement in recent years. New fishing restrictions since the 1980s and two good years of river flows have helped recruitment in the reservoirs. Movement past dams was a rare event, and the fish moved mostly down stream. While fish ladders were built into the dams for salmon, salmon swim near the surface of the water and the ladders are built to accommodate them.
Navigation locks provide the main method of movement around the dams, but that mechanism is limited.
Providing a way for the sturgeon to get around the dams may help, if not in spawning, at least in making more food resources available. But we don't know how well that would work because they are normally motivated to go upstream to spawn. But at least they could reach better feeding grounds. De Vore's team also found that the lower river had much better habitat for reproduction with the substrate being better for egg adhesion. Sturgeon are also sensitive to water temperature and velocity and this too is better on the lower river than the artificial lakes above the dams.