Mountain streams - dry or nymph for prospecting?

[saflyfish]

Approaching and fishing a berg stream is often a daunting task.What fly would be best to prospect for trout - a dry or a nymph?Would a brown/rainbow be keener to take a dry or a nymph?
Ideas please?

[Korrie]

it all depends if you are a dry fly fisherman or a nympher?
I would say nymphs are better, if you dont see any visible rises, but the best will probably be dry fly with a nymph dropper.
Once you catch your second fish on either dry or nymph, you will know what the fish are feeding on.
I would suggest an #14 or #16 Awesome Possum Tabanas, with a small GRHE with a gold bead, or a Gold Bead PTN. If I follow Pascal Cognard's advice

[Korrie]

Another interesting factor with the dry-dropper setup of the French.
the "norm" for the dropper length is SA is 1,5x the water depth.
The French fish it 1,5 to 2 meters behind the dry fly, even in shallow water.
They change the weight of the nymph to fit the depth of the water, so not to get stuck.

[Kevin James]

Mate, the New Zealand truck and trailer rig is pretty damn effective.

Fish a good dry fly that floats high and is easy to see and attach a weighted nymph below this on a 30-40 cm section of tippet.
Tie a uni knot directly to the dry fly shank and pull tight.

It wouldn't be unusual to tie and re-tie different flies and rigs up to 50 times a day depending on the stretch of water I fish.
For deeper pools and runs a double nymph rig works well as does a single big dry.
Don't limit your thinking to simply one rig that works for all conditions.

The rainbows love the faster riffles and the browns the slower back waters in general.

Go get 'em mate.

[saflyfish]

great advice there dogtooth...thanks

[dlampert]

My approach to dry or nymph is normally influenced by water depth, speed and clarity amongst other things. As a rough rule, if the water is deeper than my knee I will often fish a dropper as the fish will not always move up through the column to eat a dry. If the flow is fast I will fish a dropper as it usually gives the dry more time in the upper zone and offers them a nymph closer to where they will usually be feeding. In very clear water I will often fish a dry on its own as the fish will see it from far and if the right fly, they will move for it. If strong wind from behind, a dropper will anchor your dry when casting and allow for a better drag free drift. If strong headwind, a dropper will help your dry punch through the wind. About the only time I don't fish some kind of dropper is if the bottom is very weedy and I am hanging up a lot (not something you often encounter in the berg streams) or with very spooky fish where the plop of the nymph will often scare them (again, not something you often encounter in the berg). Droppers result in more tangles if you are not used to fishing them so bear that in mind. Sometimes it is better to catch fewer fish and have a tangle free, relaxing day.

Rainbows usually are found in faster water than browns but I have found a lot of the berg browns act like rainbows and will sometimes rise through 2-3m of fast water to eat a dry fly, something that they don't often do in the Western Cape. Fly choice when prospecting should be big enough to attract their attention but not too big so that they think twice before eating it - size #14 is a good starting point. Long legs on a fly scare less fish than bulk. A dry fly causes less commotion through a run and you can always fish the same run afterwards with a dropper if you have had no action. Nymphing a run first will usually disturb more fish, especially if you are fairly new to river fishing which I gather you are by the question you are asking? Hope I haven't confused your more ;-)

[Bryan]

@Korrie, very interesting....almost like using your dry as a strike indicator ala-Vaal style