No its not certain that they are stunted. But they are small. It is either or and both make id harder. Not necessarily so on the small LMB = large sunfish. If the sunfish are maturing early in response to LMB predation in an attempt to establish a viable population then their energy will go more toward reproduction and less toward growth. This coupled with limited sunfish food from a unfertile pond can lead to stunted populations of both LMB and sunfish. You may get a few large sunfish and LMB but the bulk will fair poorly. This can occur where most of the large sunfish have been caught and removed.