Since the KZN River catchments receive summer rainfall, the water can be discoloured at times during spring and summer. During warmer months of the year yellows feed with great enthusiasm and thoroughly enjoy the warm conditions. The problem fly fishers have with summer is that many of the rivers where yellows live are almost impossible to fish during the wet summer months. That’s because heavy rains turn them into wild raging torrents. This is particularly true for the Umkomaas River.
After first decent rain when currents speed up and water temperature increases fish start moving upriver to seek out spawning areas. A turn to heavier nymphs will then be the order of the day, and while many of the same patterns will remain effective Czech nymphing techniques are then most productive. Flies include a selection of heavily weighted Czech nymphs to imitate caddis and mayflies in size 8 - 14. These flies are only used when Czech nymphing or fishing a tandem rig in fast flowing water.
First, the angler fishes very close to where the yellows lie in the river, with probably only about 2 to 4 metres of fly line out of the tip. Many using this technique do not use a fly-line at all. The flies are pretty large and must be heavy to get down to the bottom where the fish are feeding on nymphs. Despite the extra weight, flies are tied as slim as possible to ensure they sink fast. The heaviest fly is generally in the middle of the team of flies. The flies are vividly coloured, this does not mean that imitative flies are not used but mixing it up can produce great results. The flies are positioned 20 inches apart, with the heaviest fly typically in the middle position. The flies are tied on using droppers off the leader. This is usually accomplished by joining two sections of leader with a double surgeon’s or blood knot and leaving a tag hanging off. The most exact fly imitation is usually on the point of the team of two or three. The cast is nothing more than a lob of the weighted flies upstream. Don't try 'flicking' a short cast, i find the best method of 'casting' is (if right-handed) to face downstream, let the line drift down below you, and with the line tight and the rod-tip right at water level, do a 'back-cast', that turns into a forward cast as you swing your body to face upstream. Try pulling the flies downstream slightly faster than the speed of the current, this can be deadly when the dead drift isn’t and it puts a bit more life into the flies as the fish think that the insects are swimming downstream.
The typical set up for Czech Nymphing is a long rod rather than a shorter one, the ideal being a 10ft although a 9ft will do the job. You will need a 4/6wt rod, reel, 60 yards of 20lb backing and a floating line to match.Leaders are typically one length of line, not tapered. Fluorocarbon line is used, because it tends to sink faster. The leader is generally around 3 - 4 metres long and needs to be strong enough to account for the fact that these fish hit flies hard in strong currents and is hooked close to the angler.
When targeting these speedsters in slower, deeper water, upstream nymphing will bring results. Flies can be presented close to the surface, but it’s usually most productive when fished near or on the bottom. You can fish it with an indicator or tight line presentation. To achieve the right depth when fishing rivers, you may need to put the pheasant tail nymph as a dropper with a heavier fly on the point. Dead drift these nymphs, flies drifting at the same speed as the current will usually be your most effective way of connecting with yellows. 5wt fly rods are the norm, standard WF floating lines and reels loaded with 60 yards of 20lb backing will be sufficient. 3X nine foot tapered leaders and 3X, 4X monofilament tippet material are used. Some of the cleaner water will require longer fluorocarbon leaders of up to 16ft tapering down to 4x, 5x. Flies include smaller caddis and mayfly patterns in black and olive in sizes 14 – 18. Dry flies such as CDC Caddis, Elk Hair Caddis, Adams and Trico Spinners in sizes14 – 16 will have most bases covered.