There weren't any walleye, and only a few bass before the dams. But, as everyone continually learns as time passes, once you introduce something to a new environment, quite often it thrives in its new digs(i.e. Columbia River shad). And once something is introduced and thrives, it is literally impossible to get rid of. Plus, it's not just us silver scale chasers out there anymore. It has become a BASSMasters and InFisherman kind of world. The number of bass and walleye would probably go down, but they would have a lot less acre feet of hunting grounds to patrol to find the same number of smolts(or more). Think back before the dams, there were no walleye, no shad, and a relatively small population of bass. Almost everything the river produced in the way of nutrition went to feeding anadramous fish. Now, there are millions of shad, and hundreds of thousands of walleye and bass in the system competing for the same food, and hence, the smolts have also become food.