Mid-winter is the time to go after mountain whitefish, and the Weber River is a great place to do it. Several other Utah waters contain good numbers of whitefish, including the Logan, Blacksmith and Little Bear Rivers. Action can be good at any of these streams, but the Weber is probably the easiest place to find and catch the fish.
Mims Barker (The Fly Line) says the Devil's Slide area near Croyden is one of the better places to go after whitefish. There are a lot of pools in that area, and the fish tend to school up in the deeper, slower water. Look for a pool 2-5 feet deep, with a medium flow. If you walk the bank above the stream and watch the water carefully, you can often see big schools of fish in the larger pools.
When you find a likely pool approach it quietly and work a nymph slowly along the bottom, aiming right for the fish. Most small nymphs will work, but Mims says light colored stones and red beadheads have been particularly effective. Use enough weight to get the nymph down deep – you want it to bump around the rocks on the bottom.
Mims suggested a good rig for whitefish: Put a little weight on the end of the leader, come up about five inches and tie on a dropper and nymph, then about 12 inches and tie on another. The shot will bounce in and out of the rocks, and the first nymph will skim along the bottom. The second nymph will be up a bit higher. Sometimes you will catch fish on both, at the same time. Again, you want just enough weight to get to the bottom.
The warmest part of the day is generally best – 11:00 to 3:00 this time of year. On a good sunny day, the sun will warm the water a couple degrees, and that makes the fish more active and hungry. A cooling trend turns them off. Fish when the water is warming.
Whitefish are closely related to trout, they are an excellent sport fish and very good to eat. They reproduce prolifically in Utah's mountain streams – they are not stocked – and anglers can harvest a few fish without causing any damage to the population. The whitefish limit is 10 fish. Most whitefish caught will run 8-12 inches, but 16-18 inchers are not uncommon. Try them breaded and fried.