Having fished that lake very seriously since 1987 Ive never seen a 3 pound fish from Rathbun. My own best was a 2.30 and Ive heard of some 2.5 but never seen a legit 3 pounder. I did hear of a 20 inch fish in Sept. one year nut it was skinny and didnt weigh much over 2 1/2 . There has to be a few big ones in there. I saw a DNR report in the mid 90's and if memory serves me right it takes 6 yrs to grow a 14 inch fish on Rathbun.The life cycle doesnt last much longer than that thus the lack of fish in that 2 1/2 to 3 pound range.