U, crappie growth in Mark Twain is closely tied to their primary forage, gizzard shad. Crappie growth is good when so many shad are hatched that the shad grow slow and remain small enough for the crappie to eat all summer. Factors that regulate shad are more complex, but are associated with several environmental factors, like high water, as you have noticed. Crappie fishing in 2011 was exceptional because there were lots of little shad for the crappie to eat during 2010, resulting in very good crappie growth and great fishing the following year. Average size is declining because growth hasn't been nearly as good the last couple of years.