Fresh water
Fresh water

The secrets of harling

Estimated read time
Mike Davis
January 2007

When the wind ruffles the surface of the lake and the trout are chasing smelt it is time to get out the harling gear. The best months on the Rotorua-Taupo lakes are November and December, but with a little experimenting fish can be caught throughout the year.

My very first memories of fishing began as an energetic kid of four years old who was lucky enough to spend lots of time with his brothers at their grandparents bach at Kinloch, in the Western Bays of Lake Taupo. Every morning at first light and as evening crept closer our grandparents were bombarded with persistent cries from the grandchildren about going out in the boat to harl around the edges of the surrounding bays.

Our introduction to the sport was the beginning of a life-long obsession of chasing anything that swims and had fins on it. As with many other youngsters harling and trolling proved to be a perfect introduction to trout fishing and has provided many wonderful fishing memories.

Over the years changing technology has seen boats become better looking, faster and more comfortable, while the tackle used has become far more angler friendly. Times have changed from the old 14 foot 6 inch Sea Nymph boat with the 50hp Mercury motor and the old heavy fibreglass fly rods that bent right through to the butt when under load which were paired up with the big Hardy St John fly reels. While the gear may have become far more angler friendly and electronics like depth sounders and fish finders making finding the fish much easier - the same basic principles still apply to achieve success.


In the large lakes of the Central North Island such as Lakes Tarawera and Taupo harling is predominately done by following the contours of the lake.

Over the years experience would tell us that by looking over the side of the boat and being able to see the lakebed on one side, while over the other side of the boat the lakebed dropped away into the blue-green depths would have us fishing in approximately three to five metres of depth.

By following these contours we could cover large areas of water until feeding fish were found, then turn around and repeat the run.

Nowadays with the help of sophisticated depth sounders these contours are easier to track, especially on unfamiliar waters. But there is no substitute for local knowledge and that comes only through spending time on the water, learning about different lakes and where fish are found.

Pat Swift develops his own effective smelt patterns for harling.


When it comes to harling the most productive lakes to fish are the ones that are predominately based on baitfish being the main food source such as smelt and bullies. In the North Island these lakes are found in the Rotorua and Taupo districts, which are world famous, but also, include all of the Waikato hydro lakes. Lakes with insect-based food supplies like Otamangakau and Kuratau on the Central Plateau tend to be better suited to fly-fishing.

The most productive times of the year to target fish harling are when the smelt move into the shallows to spawn, which happens twice a year - once in spring and again in autumn.

The most important ingredient in all fishing when chasing predatory fish, whether it is fresh or saltwater fishing, is to find the food source.

Scientific studies done in Lake Taupo have proven that trout will travel great distances when following the smelt around the lake.

In Rotorua the experienced local fishermen concentrate on the shallow eastern edge of Lake Rotorua from the Ohau Channel to the airport in spring as the smelt move through the channel from Lake Rotoiti to spawn in the shallows.

While spring and autumn are the favoured times for harling, good fishing can be had throughout the summer especially, in the first hour of daylight or during the last hour before dark. During theses times trout will often be seen splashing and chasing smelt in the shallows. Once a strike is had on the line or a fish has been hooked and landed it often pays to do a u-turn and move the boat around and work the same beat again as often the fish are there working together in good numbers.

When covering the same piece of water it is a good idea to work a wide arc around the fish and not motor back through the action.

Sometimes when the trout are feeding hard many can be caught in a very small area when conditions are favourable. I know of some Rotorua guides who regularly go out on the lake and catch 30-plus fish in a session.

The best conditions to go harling are when the wind is rippling the surface of the lake.

Fishing can be good in sunshine or on overcast or rainy days; but by far the worst conditions are on hot, sunny calm days when the trout can see the line and are easily spooked. Some of the best fishing can be found in rough conditions when the light entering the water is broken up, but if fishing in calm, clear water it helps to have the flies as far back behind the boat as possible. What does help in such conditions is to switch to deep-running lines and fish in deeper water.


It is important to use the correct line for the water being fished, as the depth at which the flies are presented can be the difference between success and failure. For example, Lake Rotorua averages only five metres while Tarawera and Rotoiti are much deeper.

When we were young our harling rigs were set up with fast sinking fly lines with over 100 metres of backing, which were attached to very old fly reels. Once the whole fly line was out past the rod tip we would strip another 33 metres of backing out and with our boat travelling at a walking speed we would be fishing at approximately five metres. With the leader and fly been added to the rig our flies would be fishing at around 50 or 60 metres behind the boat.

The most popular set sold in shops nowadays is a light Alvey reel with two or three colours of lead-core line joined to 100 metres of backing. Each section of coloured lead line is 10 metres. More lead line can always be spliced onto the end if greater depth is needed, or conversely it can be cut back. One way to find the best depth is start fishing with lines that cover different depths, and when the right combination is found either switch to all the same lines, or let out more or less line and backing to achieve roughly the same result. If using a short line, add extra trace to get the flies further away from the boat.

These sets come fully rigged for as little as $100 and are a great way to get started. Another popular line is the deepwater express which is short and extremely heavy. Similar to a fly line in appearance it is the same weight and diameter throughout, unlike a fly line which is usually tapered and heavier in the thicker section.

With the deepwater express the flies track slightly differently and move in more natural manner on a horizontal plane, instead of the nose of the fly being pulled up slightly as with other lines.

Prime rainbows can be caught on Lake Rotoiti around the margins in spring and deep jigging with smelt patterns through summer.


The speed of the boat also affects how deep the flies will be fishing – the faster the speed the more the lines will be pulled up towards the surface.

This is why fast sinking flylines and lead core lines, which sink very quickly, are the norm. The average boat speed for successful harling is around two knots. In the good old days when a 50-horsepower motor was a big engine you could harl comfortably on the big engine, although they did tend to oil up and start smoking so a short run at high revs was needed to clear the plugs between catching trout.

Modern engines are much bigger and more powerful, and while four-strokes have eliminated the oil factor, they are usually too fast even at low revs and an auxiliary is needed for harling and slow trolling. The alternative is to tow a bucket, which also works well.


When it comes to rods most boats will run two or three rods out the back and it is important that when running more than two rods the outside rods are longer than the middle ones, and they are pointed at right angles out the side. This ensures the lines are kept apart and avoids tangles. Fly rods are useful for this, with shorter trolling rods in the middle. When letting out the gear run the boat in a straight line, so start the run well out from the intended fishing water. If the longest lines are run on the outside, it will make turning less of a hazard.


Large fly reels make very good harling reels and with a large arbour can store plenty of backing and also retrieve the line quickly. But you can use reels like Alveys and the reels used for lead lines. A word of warning – keep fingers away from the handle when a fish strikes as it will spin quickly and rap the knuckles, and don’t try and stop the trout.

Another variation in reels is the use of small baitcasting reels which are usually intended for light saltwater work, or for trout jigging. They have a high retrieval rate and have become popular for those prepared to invest a little more money in their fishing. They can hold a couple of colours of lead line and 100 metres of backing. These reels sit on top of the rod instead of the traditional fly reel position under the rod. They are light and have very smooth drag systems


Leaders vary from lake to lake but as a general rule your leader length can not be too long. I have heard of some people fishing in calm conditions using up to 20 metres of leader to get their flies as far away from the main line as possible. But 8-10 metres of 4.5kg breaking strain mono is more the norm. It is a fine balancing act because the longer the leader the more the flies can rise towards the surface.


The selection of flies available is massive and over the years more patterns for specific applications like harling and jigging have been developed by inventive fly tiers like Pat Swift. Most of the experienced guides that work out of the Rotorua region start the season working darker flies such as Green Orbits and Ginger Micks and as the weather improves toward Christmas the flies become much lighter in colour with patterns like the Grey Ghost, Parsons Glory and Jack Sprat being more popular. The flies used on the Rotorua lakes tend to be quite large to match the large smelt in the area with flies in hook sizes four and six being the biggest sellers in the tackle shops.

On Lake Taupo smaller flies are used to reflect the smaller smelt in the lake, with sizes six and 8 the most popular.

Light coloured flies are generally better on lakes with clear water, like Okataina, Tarawera and Taupo, while on weedy, muddy or tannin-stained lakes dark coloured flies will work well.

The colour of the bodies of the flies can also vary within a certain pattern.

Many Rotorua and Taupo fishermen will use lime-bodied Grey Ghosts in overcast and windy conditions, and as the sun brightens they change to silver-bodied Grey Ghosts.

These general rules also work in low light conditions as at dusk.

These are not the only successful fly patterns with the range of rabbit flies being very popular for many years. They are streamlined when wet and the pulsating fur in the water can be irresistible to the fish. Other patterns such as the Red Setter are never very far from the front of the fly box.

You can now use up to three flies at once, and it is common to have two different patterns on each line. They can be set up with the trailing fly half a metre behind the first fly, with the connecting mono tied to the shank of the first fly. Or, use a small swivel for the connection and have the first fly sliding above it, which effectively conceals the swivel.

Use dark coloured flies in low light and silver patterns in sunlight.


Harling is not just restricted to using flies and the wide range of lures like Cobras and Tasmanian devils are very successful with patterns like the Traffic Light, Green and Gold, Spotty Gold and the Clown being very popular.

The good old favourite spinners such as the Black Toby, Billy Hill and Mother of Pearl can also be used for shallow-water harling and are often used in tandem with a fly running a metre in front of them. The fly usually runs free on the trace above a swivel with the lure a metre behind it.

Harling has to be one the most relaxing forms of trout fishing that one can experience and is still a lot of fun because the fish fight well on the light tackle. Harling is a great way to start kids in the sport of fishing and is an enjoyable family outing; and in the right conditions and the smelt are spawning it can also be one of the most productive methods of trout fishing.

Survive the Dive
Survive the Dive

Free online dive training for all!

Have you played Survive the Dive? The free online diver training and certification platform is live today for all divers, spearfishermen and recreational skippers of diving boats.

Play quiz

Related Posts

Featured Posts

Drop NZ Fishing World a line!

When we get home and clean the boat we'll get back to you.

Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.