Find the warmer water. When we decided to pack it in the other day we trolled in for the heck of it. Picked up a 13.5# brown in about 90 fow on a ssw mag right on bottom. All morning the temp had been around 70 deg to about 85 feet down then started dropping. So my guess was that he was hanging where the first big temp break intersected with the bottom. Just a thought, hope it helps