People culling a species negatively impacts the species they are trying to protect... not to mention the entire ecosystem. For example, killing a pike to save a walleye... might make sense to some, but I bet that pike eats (or would prefer to eat) a lot of suckers and whitefish - no spines, whitefish are fattier, etc. I have caught a lot of whitefish in rivers in the Spring... and whitefish spawn in the Fall. So, what do you think those whitefish are doing in the rivers? My guess is they are following the spawning fish (like walleye) to eat the eggs/spawn. they also eat a lot of fry. And there is only one or two species of fish in these parts capable of eating a large whitefish or sucker.
Yellowstone is a perfect example of the need for alpha predators, and what happens when 'man' messes with nature's balance - and what can happen when that balance returns.
I too have found that pike populations seem to dwindle when bass arrive on the scene.
Culling in the interest of predator/prey relationships is incredibly shortsighted - and just plain illogical.