The water is too high at the moment. But if it stays cold and the water drops visit the Milton at Crathes just walk to the river. You will not see fish actually spawning (cos they get shy) but you will disturb the smaller males at the bank, who will move out into the river to be attacked by larger ones out there. As the fish move a wave of activity will move across the river. It csn take 30 mins to settle as the bow waves run across the pool.
Basically the tail of any gravelly pool with have fish at the moment. And spawning will take place in the early evening and morning. I took a tour of the dee catchment last week and every pool we visited had fish moving.