I’m not entirely sure how the deeper and colder water around the Silver Bay area affects whitefish or herring. I’ve seen both along the TH breakwater wall just cruising along and we’ve seen them out on the lake from the boat too. They never seem to be more than 20-25 feet down but most of the water that gets fished and where the fish are seen is between 100 and 200 feet. I’ve been over 300 foot water near TH but didn’t see any herring or whitefish.
I don’t know enough about the preferred water temps, preferred depths or just not enough about either fish to really answer your question, but I’d assume that they can be caught up in the Silver bay area. I don’t fish that area much, mostly TH and Knife River.