Here's another thing you can do to reduce the amount that your smoked fish stick to the racks: After you have set the fish on the racks in front of a fan for an hour or so to dry off the surface of the fish ("develop a pedicle"), which is necessary so the fish will absorb smoke flavor well, before you stick the racks in your smoker, pick each piece of fish up off the rack and then set it back down, so it won't already be glued to the rack with dried brine when you stick the fish in the smoker.