Spines effect movement as well as predation. These fish live in very diffrent enviroments and it is not suprising that they have fins of diffrent sizes. I bet that there is a graduate thesis on fish ecology and behavior in that topic.
Lakes that are in need of crappie managment are generaly lakes that already have stunted crappie populations with little or no predators. I would guess that this is not a matter of one good crappie year class or even three. But rather that age 0 crappie out compete other age 0 fish for zooplankton and cause repeated year class faliures. BG have been shown to prevent successful walleye spawns at high densities, not through predation but through competition for zooplankton resources. Because crappie spwan in mass before other species crappie fry could desimate a zooplankton comunity. Stocking fingerling predators circumvents this problem.
Most likely it doesn't matter what you stock into a stunted crappie pond, as long as it eats fish. I would suggest that instead of planning for a boom crappie spawn plan for bust bass spawns. Taking steps to increase bass recruitment may be an effective step to prevent the exclusion of bass.
