without knowing for sure that water body , it might be there just are not many numbers of them in there , some spots just don't hold enough bluegill to make them a good spot for bluegill ....
its a challenge some times to find them , but on a small water body "if" there were numbers of them to target it would seem you would find them with what knowledge you have of that lake ....
if they are in there , they might be on the edges of grass beds , but my bud who fishes every summer up there in that area never shows me any bluegill ....