I too have fished for atlantic salmon in tidal water. We fished at the last couple of hours of the falling tide, with very small sparse dark colored flies. You can do very well fishing these tidal pools since by definition the fish are fresh, and have not been pounded with a thousand flies. Let me tell you something, hooking a fish this fresh in tidal water is a blast!!!
Once the tide starts to turn, the salmon sense this and become very active, often darting around and putting on a show. It's a lot of fun to watch them then go up river in a few hours the when water keeps rising.
Oh yeah, I fished on the Humber as well, and my guide could tell me the time the fish would reach shellbird island pool...
well, off to Labrador July 25th, can't wait...