I have been smoking some of the fish I catch. this is smoked lingcod and copper rockfish. I have been using a basic recipe;
1 cup of soy sauce ( I like to make the fish a little on the salty side so might add a little more than just a cup)
1/2 cup brown sugar
pinch of two of garlic salt
few dashes of worsteshire sauce
pinch or two of sea salt
pepper
Add some water if you don't want it too strong.
I put fish in Ziploc bag, add the brine and marinate overnight. Smoke on low/medium for about 4-5 hours depending on how thick the fish is. I prefer the lingcod over rockfish seems to have a better texture after smoking. Apple or cherry woodchips seem to work good.