Fly fishing - The Standard Tongariro Nymph Rig

Summer’s been and gone for another year and the days are rapidly getting shorter and cooler.

Many streams and rivers are closed, or about to close, so that means it’s time to hit your favourite spawning rivers and streams.

For many, this entails an annual pilgrimage to rivers such as the Tongariro or Ngongotaha, but there are plenty of other opportunities out there.

The Tongariro must be one of the most heavily fished rivers in New Zealand, particularly over winter. It’s amazing how this river hooks anglers into getting up at 5am so they can stand in ice-cold water up to their nether regions while braving sub-zero temperatures. But once you feel that deep throb of a solid rainbow on the line, all thoughts of half-frozen fingers and toes melt away and it all becomes worthwhile.

Many come to the Tongariro for the promise of easy fishing, and we have all heard stories of days when big runs have gone through the river and people couldn’t help but catch fish. However, unless you live there or have the freedom to get there when it’s on, the reality is that it’s a bit of a lottery based around being in the right place at the right time. For most, trips to the Tongariro are often pre-planned, so you get what you get, and more often than not, they are the ‘should have been here last week’ trips. But that’s just fishing for you, so it’s up to anglers to make the most of it.

The Tongariro is a great fishery, and even when the fishing gets a bit tough, there are still plenty of fish in the river. It’s often just a matter of modifying or changing tactics to suit the conditions.

For a start, let’s take a look at the standard Tongariro nymph-fishing rig used by the majority of anglers. It consists of a 7 to 9-weight rod and floating line, three-metres of level leader to a heavily weighted nymph, with a catcher fly trailing on a short tag off this – and to top it off, a
huge, fluffy indicator is attached to the flyline’s tip. This setup works well and accounts for thousands of fish each year, particularly in many of the main pools where the depth is around 2m and there’s a nice steady flow.

As far as rod weight goes, it’s really all about personal preference. The bigger the rod, the better it handles the big bombs needed to get down to the fish, plus it’s also easier to cast further and subdue fish in fast water. However, they are also heavy, particularly when you’ve been casting with them all weekend! Using a lighter rod means lighter tippets can be used, and you get more feel when playing fish, but the trade-off is having to use more effort when casting, as well as reduced casting range.

A good quality high-floating line allows for easy line control and helps to hold up the all-important indicator. A high floating indicator that doesn’t get pulled under by the weight of the flies is a must. Often they get a bit soggy after a few
hours of fishing, and when this happens, replace it with a fresh one. A sinking indicator makes it hard to decipher takes.

For a good floating indicator I use Glo-bug yarn, dunk them in Dry Fly Silicone Mucilin, and leave them to dry in the hot water cupboard or a sunny window sill for at least a week. Just be aware that it has a very pungent aroma that will stink out your hot water cupboard, so you may require a very understanding wife! They will last a lot longer if completely dry before use.

Having two contrasting colours in the indicator (such as white and red) helps ensure it is visible in different light conditions. Castability is another thing to consider, as larger indicators create more wind resistance, making casting harder as well as reducing casting distance.

When it comes to leaders, there is always the tapered versus level debate. Tapered leaders help turn the flies over, whereas a level leader is harder to cast. However, a fairly fine level leader creates less resistance to the sinking nymphs, allowing them to reach the bottom quicker and stay there longer. Winter fishing is all about getting the flies down in deeper water, so a level leader is more of an advantage than a disadvantage.

As far as leader material and strength goes, it is important that you have confidence in what you use. Good quality material is important, as this is the weakest link between you and a hooked fish. Make sure you check the strength of your spools before going away on a trip, as leader material deteriorates over time. Even newly bought spools can be faulty – after all, who knows how long they have sat on the store shelf or in a warehouse?

I prefer to use fluorocarbon, and the brand that I’ve had confidence in for more than ten years is Double X. I use between 2.7 and 3.5kg (6-8lb) breaking strain for the Tongariro, but this is quite light compared to many people, and if you prefer to have a bit more security for when you hook that monster of a lifetime, that’s fine. I find 3.5kg to be ample for most situations, and if the fishing is tough I go down to 2.7kg. Not only does the finer leader sink faster, but it also makes the flies look more natural to any curious trout.

Often it pays to have a finer tippet between the bomb and catcher fly than the rest of the leader, so that if you do get broken off on a fish or snag, you don’t lose the whole leader.

Leader length is important, as it must be long enough to allow the flies to reach the bottom. The standard rule of thumb is one-and-a-half times the depth, so the usual three-metre leader will effectively fish water up to around two metres deep. Consequently, if the water is deeper than this, the leader must be lengthened, whereas in shallower water the leader can be shortened. Keeping the leader as short as possible helps maintain good contact and improves take detection, as well as making it easier to cast, but it is far more important that the flies can get down to the fish.

Finally, let’s look at flies. Two flies is the norm, with one being the weight to get down, while the other is the smaller catcher fly. The job of the bomb is to get down fast, so it needs to be very heavy, compact and streamlined. There are many varieties out there, from tungsten beads and bodies, to simply using split-shot on a hook or attached straight to the leader. Different weights are required depending on the depth and speed of the water being fished, with the only limit on how heavy you go being whether or not you can cast it. It is amusing watching anglers flinch on the forward cast, waiting for the inevitable whack to the back of the head as the bomb whistles towards them.

I am not a fan of the classic Bugeye with its large weighted eyes. I used
to use these when I first started fishing the Tongariro, but found that every so often they had a tendency to get out of control when I mistimed a cast, and would slam into the back of my head. They also often spin when being retrieved, which twists up the leader.

The catcher fly is usually attached to a 30cm section of tippet that is tied to either the eye or bend of the hook of the bomb. This fly takes the bulk of the fish. Egg patterns are generally the most successful, with the good old Glo-bug being a deadly pattern that still works well. My favourite colour combo is salmon-pink with a hot orange spot on a size 12 hook. The disadvantage of this fly is that it is used by so many anglers that it becomes less effective at times, and because of its fluffy nature it slows down the sink rate. Using a little tungsten-beaded catcher instead helps in getting to the bottom, and fluoro-orange beads are proving to be very successful, too. If the brighter, gaudier flies aren’t doing the trick, changing to a small black- or copper-beaded fly may trigger a response.

Like all methods, this Tongariro nymphing rig does have limitations, with the main one being that it is easy to lose contact with the nymphs, especially when fishing shallow or slower water, or where there are swirls and the currents are mixed up. The long distance between the flies and the indicator means it is easy for the angler to be unaware when a fish is chewing on the flies. The two best signs for not having good contact are subtle takes, and missing and dropping fish. By ‘subtle takes’ I mean the indicator tends to slow down or go sideways, rather than more positively diving under the surface.

So a great way to easily improve your catch rate is to maintain good contact with the flies. To achieve this, make sure the nymphs land the full extension of the leader upstream of the indicator. If they don’t, do a strip or mend immediately after the cast so that the indicator is pulled downstream a little, as this removes any slack in the leader. When fishing shallower water, closing up the distance between the nymphs and indicator – by either shortening the leader or moving the indicator down the leader – makes a big difference. 

	This article is reproduced with permission of New Zealand Fishing News 2010 - by Aaron West Re-publishing elsewhere is prohibited