I hope I am telling you correct on the gills. I know May and June are prime months for them and caught them nesting as late as August. We go every full moon phase and find them on the nest and usually catch some monsters to the point you can get picky on what you keep. Something else you can try for them is drifting. Try fishing some nesting areas and just basically drift nightcrawlers or even minnows in about 10 to 12 ft of water. Let the bait bounce on the bottom or just off the bottom a little bit and it is a good way to cover a lot of ground. Once you find a few big gills just hang around the area a little while until you start getting smaller fish and then move on a little bit untli you find the next nest. Just remember the big ones will be a little bit deeper than the smaller ones and you may not be able to see their nests. Have Patience.