To try to add to what Theo said above...
In a past discussion of the relative merits of crappie for small ponds, Bob Lusk introduced the concept of the unpredictability of the crappie spawn...one year small numbers, another year huge numbers. Unpredictable. To me, that is a critical aspect of the discussion. It would seem to be almost impossible to adjust predators based on this unpredictability, leaving success largely to chance.
