The reason you should stay with the dry-dropper combo instead of fishing two nymphs under an indicator is that as the water starts to heat up more terrestrials will start flying.
When it comes to book ending the summer months we all want to carry on fishing the dry fly for as long as possible. Our only problem is that while the water temperature warms up quickly into the afternoon, the mornings are starting to cool down and on overcast, windy days fishing just a single dry fly isn’t going to produce consistent fish all day long.
Through March and April our rivers are still running low and clean from the prolonged summer and the tourist anglers have finally left our shores so it actually becomes a wonderful time to get out on the water as there is less pressure on the resource.
The dry combo
So how do we stay successful and still allow ourselves to fish the dry fly as we head into autumn? Simply put, we fish the dry fly as an indicator and tie a nymph off the shank of the dry fly hook approximately 1 metre below it. Sometimes I fish the nymph up to 1.3m below the dry, depending on the depth and speed of the water.
As we get deeper into autumn the overnight air temperatures will drop into single digits but the daytime temp’s can still get as high as 25 degrees. With this huge temperature variance insect activity will be low until the water starts to warm up around the middle of the day. With less insect activity, especially terrestrial insects such as cicadas, crickets, grasshoppers and the like, the trout are less likely to take off the water’s surface in the morning.
At some stage they will land on the water so you can still expect to pull some fish from the surface as it warms. I have become a fly fishing snob and if I have the opportunity to catch a trout on the dry, will take it. To me, a fish on the dry is worth ten on the nymph.
The dry-dropper system is a very versatile technique, and in most water this is my personal favourite way to target trout. Catching sighted fish on the dry fly is the ultimate in our sport. But there are times when you can see fish down deep and they just won’t come all the way up to take the dry. By adding the nymph you get to target fish in two different depths. When the fish are sighted the action is still superb.
Types of Water
Fishing dry-dropper is better suited to small to medium sized rivers. It is a very effective way to target sighted fish, especially when fish are feeding in runs up to a metre deep. There is simply no better way to cover runs and riffles than with a dry dropper combination. When the river spreads out or if light is too hard and you have to cover the water “blind” (covering likely looking water without sighting fish), this is by far the most productive technique.
It is also a great way to pull fish from pools, especially when they’re feeding in mid-depth currents or when swinging in the tails of the pool. When fish are high up in the head of the pool and down deep this set up is harder to control and not as productive.
While working through very fast or pocket water the dry-dropper is very useful. Often late in the summer fish can be sighted sitting in the slack water just off the edge of fast bubbly water. This is when the weighted nymph can help to stabilise the dry so it sits in the quiet water for a longer period of time, aiding in a drag-free drift.
In larger rivers it can be used along the inside edges and can be very successful in hooking browns that line up behind and in front of boulders that break the current up on freestone rivers. On faster flowing rock and boulder rivers don’t be afraid to fish a large dry. A terrestrial pattern such as a Swishers PMX or Turks Tarantula is buoyant and can hold up a tungsten-weighted nymph. Fish can see the fly from a long way and are often prepared to lift a couple of metres to take the large dry fly.
You can see that the dry-dropper really lends itself well to fishing in the back country, particularly in the slightly smaller tributaries of the main rivers. In the evenings the technique can be used with a smaller dry and an unweighted nymph on large pools during hatches. Sometimes the fish are feeding on emergers and just bulge the surface instead of taking the adults off the top. During these hatches a small dry becomes a very good sight indicator and having the nymph just under the surface can be deadly. The neat thing about approaching an evening hatch like this is that once the fish change over to feeding on the adult, the nymph can be easily taken off.
Length of Dropper
There is no real right or wrong answer here but I tend to fish longer droppers than most anglers. When I fish dry-dropper my whole aim is to fish two totally different depths. This means the fish rising up to take my dry fly never sees my nymph. Fish always consider the energy expended to get a meal. If too much energy is needed it will wait for an easier meal to come along. That way they keep gaining weight; it's output vs input.
The problem you have when you fish short droppers is that very few fish will take the dry. You can see the fish rise and drift back to take the dry, but it then sights the nymph and turns to eat it because less energy was required.
Long droppers mean the fish that eats the nymph was never coming up to take the dry and the fish that engulfs the dry never sights the nymph. Remember, the dry fly doubles as an indicator and will generally be closer to your nymph so you will miss very few takes when the trout hit the nymph.
On some of the insect-based lakes like Otamangakau and Aniwhenua fishing the dry with a dropper can produce some awesome fishing. With terrestrials being clumsy flyers once the afternoon wind picks up, plenty of them invariably end up on the water’s surface. Around bush edges it can be very useful, and hedging your bets by fishing a damselfly nymph off the shank offers a lethal combination.
On the lakes make sure you fish long droppers 1.2-1.5 metres apart. Fish in lakes tend to feed at specific depths so it is important to understand why you are fishing long droppers in the lake. Sometimes I will fish two droppers under my dry so I can cover plenty of depth. They can be harder to cast but once they’re drifting downwind the fishing can be outstanding.
Casting dry-dropper is not always easy. The longer the trace down to the nymph, the harder it is to control, especially with a heavy tungsten fly. To fish this way well, you need to learn to cast long leaders.
Leader talk is done in imperial measurements as this is the way they are sold in shop packaging. Ideally you should have a 9ft 1X or OX tapered leader, tapering down to approximately 8lb. This is attached to a micro-ring or nylon to nylon knot with your tippet out to 12ft, where your dry is tied off. From the shank of the dry fly another 5 feet of tippet down to your nymph means that the overall length of your leader will be 16-18 feet: close to two rod lengths. This will vary depending on the size of the river that you are fishing. The important thing is the longer your leader is down to your dry fly, the better your drift is and the more fish you will hook.
Watching a large dry bob its way down a run or riffle is hypnotic. Watching it get smashed off the surface is second to none, but seeing the dry dip under the water as the nymph gets eaten is also pretty cool. Experiencing the best of both worlds is a nice way to fish. When fish are out and feeding in the runs and riffles it is the greatest way to fish.
As the water cools down with the onset of winter you may catch a couple more fish with a double nymph rig under an indicator, but it’s not cricket. In the back country or on small to medium sized rivers you will catch lots of fish as you perfect the dry-dropper technique; most of all you will see more fish move to intercept your flies. This means you will learn more about trout movements and habits. Leave the double nymph for the Tongariro; the winter spawning runs will come soon enough.