Did anyone check to see if they are still stocking that body of water with Kokes? If you weren't aware Kokanee only live 3yrs(maybe 4 for the odd fish). So if they haven't been stocking on a regular basis the fish are going to die off on their own, regardless of fishing pressure....
Spawn if from mid September through November. You may catch fish that are in spawning colors, hook jawed, etc. through the ice, but they are done and just waiting to die....
Good Fishing