Inaddition to all the fine spices listed by the forum members so far, you might try pairing soy souce and a sweetener like brown sugar. I also use these flavorings when I smoke salmon and kokanee, land locked salmon.

Living by both the Columbia and Deschutes Rivers, I get plenty of fresh salmon. I avoid farmed salmon and any fish that spends its entire life in the Columbia River due to pollutants exiting in the fish. Pity, smoked sturgeon used to be one of my favorite fish.