For what it is worth, 4 years ago my wife and I stocked walleye in our 2 acre pond as a bonus fish. The pond had an established population of LMB, BG, and CC. I have found the growth rates to be very slow. The WE were six inches when stocked. The ones I caught and released this summer were right in the 16-18 inch range. Yours might not be big enough to catch yet.
That's a possibility, thanks Nebucks!