Sonar-bait observation I observed last year on Missouri River. Saw alot of balls of bait fish til around Aug then later started seeing less balls and more "long lines" showing on graph. Posted here, but got no response. Ran across some articles the other day that talked about what baitfish look like and the structure they relate to. Said larger shad school different than the smaller shad. Small shad form tight balls and larger shad form in long lines or tubes. It would appear as summer progressed to fall the increase in "tubes" or big shad meant they were growing up. I thought at the time it was due to predation causing tight balls, but author suggest that it is small shad normal instinct. Course if an arch is around then we know where to drop the line!:cool2: Other baitfish like crappie/bluegill show as xmas trees or pancakes as they like to stack up on each other. Apparently author did dives with his electroncs to verify these conclusions.