I tend to use the North American Olive Humpy dry fly on slightly rough water because of its good buoyant qualities. It has been fished on fast moving water since the 1930's.
HUMPY DRY FLY PATTERNS. Hook size 12 14 16 - $US each
HUMPY FLIES AND SMALL STREAMS
I like small streams as they lend themselves to the dry fly. I am not a purist, I love fishing with nymphs and streamers, but I find fishing with a dry fly challenging and enjoyable. Fishing a small stream has other advantages. Normally you do not have to pay a lot of money for a day ticket. Some streams are open to the public. You can change the steams physical characteristics to make fishing more fun on your next visit. By simply placing a big boulder or log across the current in an over shallow run you can deepen it. You will be making enticing new trout lies which you can exploit on your next visit.
If you have a favourite local stream you visit regularly take an active role in its maintenance. Pack a gardening hand scythe or a pair of secateurs in your kit bag to deal with problematic weeds. Consider planting flag iris near the bank to provide shelter for juvenile fish and different types of insect life. Clear the river of fallen branches after a violent storm. A bag of washed pea-shingle placed near the head of the steam will provide good conditions for female fish to lay their eggs.
Trout in small streams may run a little bit smaller than those in larger streams nearby – but even so they will not seem small fry to their environment. Often however, they will not be smaller at all, especially if they are tributaries of good trout rivers. The largest wild trout I have ever caught came from the tiny headwaters of a feeder of one of the river Itchen’s tributaries. It was fine wild brown trout that weighed a few ounces over 7 lb.
Small streams need a stealthy approach and a well-planned short cast. It is easier to scare a trout in a small stream than on a larger stream and a scared trout in a small stream creates more general havoc than in a larger one. You may be lulled into overconfidence by being able to sit and watch a trout feed almost at your feet. You are being motionless when you do so and not casting. Once you stand up, let alone start waving a rod around, your trout will probably be well on its way to the next village. Try to use natural cover like bushes and boulders to hide your movements. Stalking your prey is so rewarding. Do not wear bright colours. Choose clothing that matches the environment you are in.
If you do spook a trout in a small stream it will probably head downstream, but watch which way it goes. Trout rising ahead of it upstream may not be disturbed so that is where I would re-start casting. Within the narrow confines of the stream channel, it can hardly help conveying its panic to three or four of its nearby fellows, who will carry the message to others near them. This may not happen every time, but when it does you can say good-bye to that stretch for quite a long time.
So how do you avoid stumbling on trout who subsequently spread wholesale alarm? Try to keep a reasonable distance away from the river-bank if possible. Then you can skirt any grayling or trout you see but do not wish to fish for. Try to see the fish before they see you. This is easier to do in clear water. Never hurry. If a stretch of water or a pool seems barren at first sight, do not be tempted to walk immediately up to it. Pause, scan the water and watch. Even if you do not see a rise you may see a shape that gradually, before your eyes, becomes a trout.
In a small stream, trout lying in shallowish water will often take a fly like an attractor dry fly Olive Humpy, even if they do not appear to be actively feeding, so they are well worth looking for. On sunny days I often see the shadow of a well camouflaged small trout before I see the fish so I actively look at the stream bottom for fish shaped shadows rather than green speckled fish backs.
The Large Dark Winged Olive Mayfly
I use an Olive Humpy to imitate the Large Dark Winged Olive on rough water streams and rivers. Strange as it seems but the nymphal stage of a large dark olive nymph should be imitated with a fishing fly pattern that is brown in colour, not olive if you want to match the natural insect’s body colour. The large dark olive upwinged mayfly is an important Ephemerid on many fishing waters in Britain and around the world.
Its emergence periods range from mid-march until late April and then from mid-September to late October. On rough water streams in the Welsh Marches, where the Large Dark Olive Mayfly hatches only in sporadic numbers, its arrival encourages much more interest from the trout and more fish being taken, than on other rivers where there are large hatches.
Why is this so? I think it is down to the trout in these spate streams willing ness to feed close to the water surface weeks earlier than do their chalkstream counterparts. It may be due to the fact that more trout are taken in the early part of the season because the river lends itself to wet and nymph fly fishing than do the chalkstreams. The fish seem more ready to take a subsurface fly pattern than a surface dry. Who knows? The fact remains that the large dark olive mayfly is possibly the most important upwinged fly to emerge during the first weeks of the season.
It is the largest member of the group of insects collectively known as Olives (Beatis). Other members include the Medium Olive, Pale Watery, Small Dark Olive, Iron Blue Dun and Spurwing Olives, most of which are a lot smaller and emerge later than their large cousin.
The Dun is unmistakable. It is a large robust mayfly about the size of a March Brown, another early-season ephemerid whose habitat regularly coincides with that of the Large Dark Olive, but there the likeness ends. It has a completely different body colour that varies from a mid-olive green to a dark olive brown. Duns of late spring for some reason are paler than those of a month or so earlier.
The wings of both the female and the male are a deep ash–grey and are a very prominent feature of this mayfly since they are held particularly upright. This makes the hatching dun clearly visible even on the darkest of early spring days. The large dark Olive has a habit of holding its wings close together, which serves to suggest a darker ground colour than they in fact have. This impression is heightened especially in the male dun because the veining appears more prominently pale brown.
These wings often stand proud of the body at least 11mm or so. The heavily spurred hindwings of both duns add to the robust impression this mayfly gives when floating on the surface in the current. The body is about 12-14mm long and has two distinct tails. The lighter coloured legs tend to emphasise the general darker colour of the body segments.
The large dark olive spinner is less important to the fly fisherman than the hatch of the duns. The return to the water of the female to lay eggs takes place over an extended period during the day, not in concentrations normally associated with the fall of spinners of other species. The female crawls beneath the surface to lay her eggs. She does not die. She floats to the surface and tries to take off. Many fail in this goal. They become entrapped in the surface tension, making them vulnerable to patrolling trout.
Known as the red spinner, both sexes are aptly named, since their body is a deep red-brown with fading orange-brown to the last three segments. The legs are a pale brown-olive. I have often taken trout on warmer early evenings of late April by watching for fish feeding on the surface-ensnared exhausted female spinners as they recover from egg-laying.