From wanting “plips” not “blops” to mating flights and embracing darkness, Vaal River hatch junkie Herman “Harry” Botes breaks down the how, when, and why of the Vaal River’s legendary caddis hatches in The Mission Issue 44. Photos by Paul Botes.

The Mission (TM): Describe your first experience of a major Vaal caddis hatch.

Herman Botes (HB): I probably didn’t even notice my first experience of that hatch because I wasn’t too familiar with insects then. But trust me, if you’re standing on the Vaal River in summer, spring, or early autumn, at ducks, and you’re choking on bugs that have created a halo around your head, they’re caddis. The first time you see it, you’ll point out to your buddy next to you that he’s got a halo, and he’ll point right back at you and say, “You’ve also got a caddis halo.”

It starts at what I call “happy hour”, which is at about 4pm when the sun comes in and casts that golden glow on things. The flight starts, and once you notice bugs, they’re caddis. They are way more prolific than any other insect hatch.

TM: Is it one kind of caddis or..?

HB: The main family are Hydropsychidae, aka net-spinners. These caddis build webs under rocks which they catch stuff in, and they live in cases they built themselves. They are free-living and are not tied to the casing until they pupate. There are three species of Hydropsychidae on the Vaal. Two of them are very similar in size and appearance. The only way to tell them apart is if you catch one and look at its abdomen. One’s is a bright apple green and the other’s is more tan-yellow.

TM: So, the apple-green caddis colour is what your Plaza Pupa fly resembles?

HB: Correct. The Plaza Pupa is slightly bigger than the tan one. It performs very well in certain sections of the Vaal and in the tributaries. For the tan one, a Gold Ribbed Hare’s Ear (GRHE) just about does it. I haven’t found a pattern that out-fishes a GRHE. 

Those are the two smaller species. The big boy is what the locals refer to as the green rock worm – the Macrostemum capense. It’s a big, fat, caterpillar-like worm that hatches in spring and autumn. It normally joins the hatches in the evenings and stands out because of its size. In spring, the M. capense might be sparse, trickling off during the day. But I have seen fish come up out of nowhere for a big caddis. They are very aware of these bigger insects and will launch themselves at a big M. capense adult fluttering on the water.

TM: It’s like the steak of the meal and everything else is a bar snack?

HB: Ja. I think it’s because of the numbers and timing of the hatch. The small ones hatch at dusk, the “evening rise”. On the Vaal and its tributaries, an evening rise from spring to autumn is always caddis. If the mayflies interfered before the caddis, then the yellows would be on mayflies. However, the big species, M. capense, can happen throughout the day. It’s mating flight happens after dark, when it can join the hatch of the small caddis. Sometimes you are stumped by a caddis hatch because there’s a mating flight of M. capense and you haven’t seen that the yellows are feeding on spent adults. They are seldom particular about the pattern, even if on spent caddis. If you’re in the ballpark, you’re going to stand a good chance. I have my go-to patterns and they work.

TM: The best months to experience a Vaal caddis hatch?

HB: Early spring starts with the two small species hatching from midday onwards, and much earlier in summer. M. capense hatches from mid-morning and trickles off throughout the day. In summer, everything moves later – closer to dusk and darkness. As it goes back to autumn, the hatch moves to earlier in the day, around 5pm.

TM: Is it daily, like clockwork, or are there specific conditions?

HB: If you’re a Vaal regular, you can expect a hatch every day. I cannot tell when there isn’t going to be a hatch. Sometimes, if it’s miserable, like a cold front or a weird weather thing, the hatch doesn’t happen. Sometimes, you stand on that river, and you walk off thinking there won’t be a hatch, but if you stay longer and wait it out until after dark, when you can hardly see anymore… Boom, the action’s on!

The flies

The Leisenring Lift was developed by Jim Leisenring. When fishing nymphs and wet flies across and downstream, it’s the action of stopping your rod which forces a sinking fly to “swim” towards the surface, imitating the movement of an emerger. This is often a trigger for fish.

Cheumatopsyche photo courtesy Christian Fry

TM: Have you seen a decline in insect numbers, hatch intensity, etc. over the years?

HB: I’ve been fishing the Vaal since 1996, almost 30 years. Obviously there’s the sewage problem now and that puts me off, so I’m not on the Vaal as much. I fish further downstream. In the tributaries and the Vaal, the first insects to disappear were the stoneflies because of their sensitivity. You may find some golden stoneflies above Grootdraai Dam. Further down below the Vaal Dam there are brown stoneflies. They were the first to go.

That said, species like mayfly and caddis are very tolerant. Most of the pollution is organic – farm runoff with nutrients that boost insect populations. If you roll over a rock on the Vaal, it looks alive. Everything starts crawling. There are two mayfly species, blue-winged olive and a trico, the three caddis, leeches and all sorts of insects and molluscs. We also used to have a lot of freshwater shrimp, and they seem to have taken punishment. It could be the flooding or the pollution.

TM: When there is surface action, do you fish dry fly only, or do you use combinations of dry droppers and nymphs?

HB: If there’s surface action, because of the intensity of the hatch, the number of insects on the water, and if the river has good flow, the riffles are the food factories. Fish are under pool heads and riffles. The nice thing is that the fish are stationary in a pocket. A fish can be targeted, as they behave and rise rhythmically. It makes dry fly fishing so inviting.

There may be a hatch without dry fly action, but a fish breaks the surface every now and again. It doesn’t mean that the fish aren’t eating pupae just under the surface. You can hedge your bets with a 2mm tungsten bead head pupa in a dry dropper. Early in the hatch, I’d put a nymph two feet below a dry. Then maybe a foot and a half a bit later. Then as short as half a foot just as the fish are breaking the surface.

“You want a ‘plip’, not a ‘blop’.”

The nymph does two things for you. It anchors the target. If you aren’t that accurate when dry fly casting, then the nymph can assist with precision. You must land the fly on target and drift the fly directly over the fish. The fish will not move out of the zone to fetch an off-target fly because he’s got a buffet in front of him. You can get away with fishing a bead head because yellows are so attuned to the “plip” – the sound of a tungsten bead head caddis hitting the water. It has to be a 2mm/2.5mm tungsten bead. Any bigger and you’ll get a “blop”. You want a “plip”, not a “blop”. It just grabs their attention. Also, being above and below the surface spreads your catch rate.  

The other thing about a nymph dropper is that if you fish through a school of fish, they are feeding at different levels. As you drift the line, your nymph will swing and drag. The minute this happens, the nymph swings and you’ve got a rising pupa. It’s like a Leisenring Lift – they are very attuned to it.

TM: In South Africa, size 10 is often considered a big dry fly pattern. What sizes are we talking for these caddis flies?

HB: The small species start off big in spring. They actually drop in size over the season, just as blue-winged olive mayflies do. They may end up on a size 18 or size 20, but they normally start at a size 16 – my go-to size. At a push you can get away with a size 14. On the M. capense, the larvae are 14s or 12s but you can push a 12 for the pupae. The adults sit in that same range, but their wingspans push them to a size 10. It’s a much bigger fly.

TM: Is your favoured Air-head Caddis pattern basically imitating that?

HB: Ja, the Air-head is on a size 10 hook. The body only covers about two thirds of the hook shank, so I start short. The wings cover the body anyway. The wing length and whole fly is longer than a size 10 dry fly. I would use a standard-length hook for dry fly. Like a Tiemco 101.

TM: What are your other go-to patterns?

HB: If you want a go-to fly, use the Hermanhamer. That thing catches fish.

It’s my version of a Klinkhamer and just looks like a scruffy Klink. Charlie Craven said a caddis pupa is a cross between something that flew into your windscreen and a ball of snot, and this thing tries to emulate that. But it is so effective, it’s like a silver bullet.

The Airhead, for what it is, and what I’ve seen it do, is unbelievable. If you fish a headwater that’s packed with fish and you dead drift it through there, you won’t catch anything. The minute that Airhead moves and the nymph below it activates, the fish are on it. Even in pocket water I’d splat it down and with one pull it will dive under and boom. But if you throw it normally, they won’t react. That’s the beauty of it. With those two patterns you’re covered for the Vaal. If you need a nymph, just go for a small GRHE with a 2mm bead head.

TM: How do you approach the hatch when it starts?

HB: When you sense a hatch coming, don’t go shallow immediately, even if the odd fish shows. Stay deeper because most fish are still deeper. Like the trout in English lakes, they’ll follow the pupae as they move up in the water column. At first they’re eating the pupae at their deepest, then more and more pupae come off and move higher in the water column. The fish will start eating closer and closer to the surface until they are subsurface or in the surface film. You can also go double dropper, one at three feet and the other at a foot and a half. If you see they’re taking the top dropper, then you know they’re taking it shallower.

With caddis hatches, you can get much closer to the fish when it’s dark. Always remember: The rapids are the food factories. The fish might be rising in the rapids but are much more likely to take your dropper when they’re feeding there. The ones feeding off the top are going to be just below the rapids where the biggest concentration of food is coming through. They are going to be in the current tongues, and they’ll be lining up. There’s going to be multiple targets. On one cast you’ll drift over three fish and one of them will eat. Or you can pick them all up one by one, fishing bottom to top.

TM: You’re a numbers guy. What do you expect on a day with a Vaal caddis hatch?

HB: It’s amazing how it always starts slow, and then it always picks up. Caddis bring the fish on the feed. If I’m on 20 fish by 5pm I know I can almost double that score if there’s a good caddis hatch going on. I’ll probably get another 20 fish of which 10 will be on dry. Sometimes it goes nuts, with up to 25 fish on a caddis hatch. That’s from just before dusk until just after dark.

TM: What’s your tackle and gear setup for facing the Vaal caddis hatch?

HB: My rods are 3-weight, 9-foot rods for accuracy, if you’re picking specifically for the hatch. Ten-foot rods help in tricky currents, but your drifts are so short because you’re fishing to a specific target. You don’t need to lift the line off the water and have long drifts. Accuracy is the name of the game; you must put it in front of the fish. Sometimes fish move around, and I just watch a fish. I look at its rhythm and sometimes it moves upstream. You have to anticipate its next rise and just put it there. Those are the best fish to catch, you really feel, “Wow man, I’m good! Did anyone see that?”

“If something goes wrong, just stay calm because otherwise you will get viskoors (fish fever).”

If you’re new to it, stick with a 9-foot leader with a foot of tippet or an 8-foot leader with two feet of tippet. At dusk you can go thick, 5x will be fine. You don’t want to go to 6x and risk being broken off. I carry two reels if I fish a 10-foot setup. I have a reel for euro nymphing and a reel with a long leader setup – between 12 and 15 foot. I like to fish long leaders and I’m used to it. If it’s windy, the longer the tippet the less drag you have, and you don’t want drag when fishing the pupae that are hatching. That’s my ideal setup. For someone starting out, rather go to 9 to 12-foot leader just for accuracy. You may lose accuracy on 15ft.

Use a headtorch but turn it away when rigging or use the red light. On the river barbel don’t see the light and don’t give a hoot, but if you shine a light over yellowfish they will spook.

At that time of the evening the last thing you want to do is malfunction: having break-offs, losing flies, building leaders. You’re racing against time. You have this fantastic opportunity, so you have to make the most of it. If something goes wrong, just stay calm because otherwise you will get viskoors (fish fever).

See more photos from this Vaal caddis hatch story in The Mission Issue 44 below, for free, forever.

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