While dry fly fishing clearly ranks as the number one preferred fly fishing technique amongst anglers, I personally will happily chuck big streamers if the larger trout aren't rising on a given day. Streamer fishing is the least used and most overlooked of the "Big 3" fly fishing styles, behind nymphing and dry flies. Trout which will sit dormant as dry flies and nymphs pass by can often be enticed to lash out at a well presented streamer. And that is much of the appeal. It feels as though you can make the trout strike when you get the proper action on the streamer. More on that later.
Streamers, which imitate anything from minnows and small trout to crawfish and leeches, can be used any time throughout the season. However, especially for large browns and cutthroats, autumn is best. As water flows recede late in the season, trout become more concentrated as their living space becomes smaller and smaller (less water, less living space). This means smaller trout which have been hiding in various high water holding areas, like sloughs, are now forced to cohabitate in tighter quarters with their larger cannibalistic brethren. The big guys are quick to take advantage of the situation and will greedily chomp any smaller fish which strays into their territory in search of safety. Trout are not very nice to each other.
As trout grow, the insect to small fish ratio of their diet slowly switches to include more smaller fish, which provide a bigger "bang for the buck." Trout must feed efficiently in order to survive and the higher caloric content of, for example, a three inch parr (a young trout) is well worth the effort and it is inherently more efficient than rising repeatedly on insects. This diet switch is less pronounced in fisheries which contain huge insect populations, such as Henry's Fork, and is more pronounced where hatches are light, such as the Snake River in Jackson Hole. In either case, the switch eventually does take place. The difference lies in the size trout which will consistently hit a streamer. In the Jackson Hole section of the Snake River, ten and eleven inch trout will take even size six streamers, something you wouldn't be likely to see on the Henry's Fork.
The fact that streamers often catch larger trout should be enough to convince you to give it a try, but certain misconceptions prevent many from doing so. Allow me to address some of these common misconceptions regarding streamer fishing:
Streamers are hard to cast
True, sort of. However, with proper casting technique, they can easily be handled. The most common problem is the angler not waiting long enough on their back cast. Wait until you feel the streamer loading the rod on your back cast before initiating the front cast. The extra weight of the streamer will provide the feedback you need to get the proper timing. Dry fly fishers who never cast weighted flies often do not realize that they rush their front casts. Learn to cast streamers and you will become better at casting dry flies as well.
I will not see the strike of a streamer like with a dry fly
Usually, you can see the strike on a streamer. Whenever possible, use a streamer with some yellow or white on it for visibility. Your streamer need not necessarily be deep to be effective. Look for flashes and movement near your fly. When trout are in the mood, they will come up to or very near the surface resulting in explosive takes. Very cool.
I need to get my streamer as deep as possible, perhaps using a full sink
or sink tip line
Usually not. As stated above, your streamer need not necessarily be deep to be effective. I almost always streamer fish with a floating line, using split shot to get the fly down a bit when necessary. The floating line/split shot combo is also the quickest way to sink a fly, as long as you mend and prevent your line from tugging the fly until you are ready to put some action it. Furthermore, the floating line allows much greater line control in moving water which translates into better action on the fly - especially when you are trying to jig your fly, a very good thing to do! It ain't the meat, it's the motion.
One of the overlooked keys to streamer fishing is the action you impart on the fly. This is best accomplished by using your rod tip to move the fly rather than simply stripping in line. Just make sure you keep your slack to a minimum by stripping in line as necessary. Don't be afraid to experiment. Jig the fly up and down, follow two or three quick twitches with a pause, try a really fast presentation, whatever it takes. Try to make your streamer look alive with quick erratic twitches, yet vulnerable with occasional pauses. I call it the "I'm wounded, eat me!" syndrome. You are trying to trigger the trout's instinctive attack response.
Give streamer fishing a try when it gets windy. Not only does the dry fly fishing sometimes suffer as the bugs are blown off the water, but the extra weight of the streamer helps the fly cut through the wind.
Streamers are best fished with a six (or seven) weight rod and line, though many of today's five weight rods can handle them well enough. Make a good strong back cast and wait until you feel the fly begin to load the rod before initiating the front cast. It helps to throw a wider than normal loop when using heavy streamers. Finish with a very positive stopping of the rod tip so that the fly will turn over and contact the water before the line. This improves accuracy which is as equally important for the streamer as for the dry fly, especially when fishing for reclusive brown trout. If you streamer fish enough you will begin to notice that there are days when the fly must be within an inch or two of your target to get the desired results.
For patterns, use old favorites like the Woolly Bugger or the Muddler Minnow. They are still hard to beat. Also in this category would be the Kiwi Muddler, the Zonker and the wide variety of leech patterns, of which mohair and marabou are as good as any. Recently, the Jackson Hole area has been fortunate to have witnessed the development of two new killer streamer patterns, Scott Sanchez's Double Bunny and the JJ Special by Jim Jones. The Double Bunny matches two rabbit strips on one hook and is as big and heavy a streamer as you'll ever want to fish, but big and heavy are the trout it attracts. The JJ Special is essentially a Woolly Bugger with rubber legs in a special brown and yellow color scheme and is most effective when jigged. It elicits exciting slashing takes. Several JJ Special wanna-be's have begun cropping up in western fly bins, but the original is still the best. Try both patterns, they're deadly.