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Freshwater: Fishing the seasons

November 15, 2019
Freshwater: Fishing the seasons

One of the greatest lessons I ever learnt as a budding young fisherman on the lakes and rivers was that in order to become as successful at fishing as possible, you must continually adapt and become versatile in order to consistently deceive trout in a variety of situations. To improve in these areas I have challenged myself to fish as many different types of water as possible so I force myself to learn new skills on every piece of water I encounter.

Of course exploring like this is not everyone’s cup of tea – some prefer to fish their familiar patch – but for me the lure of the possibility of discovering the next holy grail of fishing has always been too strong

Generally if I fished a large river one day I made sure I fished a small stream the next time I went out, or I would go and fish a lake to keep changing things so I never became complacent with any form of freshwater fishing.

During the year the fish behave in a number of different ways and therefore the trout will sit and hold in a variety of waters depending on a range of factors and needs. External factors can range from air temperature to terrestrial food influences, water velocity, water depth, water clarity, water temperature and even fishing pressure.

Internal factors such as high or low fish populations in certain waterways will influence the range in which a fish can feed without competition. This will, in turn, have a bearing on the average fish size for that particular piece of water. During spawning season maternal instincts take over and fish will sit, hold and frequent different types of water and behave differently to other times of the year. As fisherman we need to be aware of these changes – they are the little things that can help us become more educated, hopefully putting us in the position to catch more fish.


Winter is probably the hardest time of the year to fish and the variance in the quality of trout caught between June and September is greater than at any other time of the year. Fish that have spawned early will be making their way back down to the lakes where they will feed hard trying to put weight back on, while the late spawning fish will still be stacked up at the river mouths waiting for their cue to enter.

In the lake around August an influx of bright silver two-year-old fish is usually a welcome addition to the angler’s bag. These fish are chasing smelt and have never spawned so they are usually in top condition.

With cold water the best techniques are very slow and methodical, making sure the retrieves of the flies are done right across the lake bed. On the rivers, the mix of fish will be very noticeable and a large part of the catch will be made up of returning kelts.

Over the last 10 years or so the spawning runs of Lake Taupo fish have been later and later each year, to the point that September and October are producing the largest runs of the year.

During September the daytime temperatures are warm enough to produce some mayfly hatches in the afternoons which helps bring some variation to the deep fishing of the last few months.

When the spawning fish are moving up the rivers they tend to sit just off the main current and will be found resting in the deep runs and pools as the move upstream before they spawn.

Spawning fish will be found in the shallow glides and will also dig redds in the tails of some pools. Try to avoid targeting these fish as they are of no use to you if you are wanting to take home a quality table fish. When crossing the river be careful not to walk where the trout have dug redds.


With the angling season opening in most places on October 1, hopefully the first few days of fishing will be fairly easy knowing the trout have, in many parts of the country, had a chance to rest from angling pressure for the previous three months.

The first couple of days out on the lakes will usually see some very easy angling with generous numbers of fish caught. In October the lake temperatures are still cold meaning that the layers of water are well mixed, spreading the fish throughout the lake at different levels and depths.

Because of this, all methods of angling are usually pretty consistent and the boaties will catch fish harling, trolling, jigging and fly fishing meaning no single method will out-fish the other until the lakes warm up in December.

The early fish caught will either be fat two-year-old maiden fish or they will be returning kelts trying to put on condition after spawning. Many fish will supplement their normal diet of smelt with the energy-rich koura or fresh water crayfish and also the shy cockabullies. As a result the best conditioned trout will be caught close to the bottom regardless of what method you are using.

While up in the hills most of the rivers and streams in the early season will be flowing at pretty high levels even though many of them will be clean. Like the fish in the lakes, the trout in the rivers will be feeding hard trying to put on weight after spawning.

Because of the extra water in the streams many fish will stay in surprisingly small streams until either excessive angling pressure pushes them back down into the parent water, or the streams lose too much water during low flows.

In the South Island many of the major river systems will have large quantities of snow melt to get rid of while the tributaries will run clean. These areas of clean water hitting the main flow are fish magnets, but sometimes the trout may choose to enter and stay up the tributaries until the main river clears.

With the water being cold it is harder to drag fish up to the surface with dry flies so early season fishing is often most successful using nymphs. Tungsten flies will sink faster than lead-beaded flies and this also means if you have to fish very small flies you can do so with a fly that will still sink very quickly.

On bigger rivers you will probably need to use a yarn or stick-on indicator as a strike detector, while on smaller water a large buoyant dry fly will double up as a very effective strike indicator. Make sure your indicator is not attached to where the fly line meets the leader as many fish strikes will be lost or, worse still, not even detected, especially when using long leaders.

I like to tie my yarn indicator in to my tapered leader with a half hitch – this means I can easily change my indicator position on my leader depending on the depth of water, making it much easier to detect and see strikes because the indicator is closer to the fly.

Over the spring months while the water is still cold the fish will tend to stay away from the faster, more oxygenated pocket water and will more likely be found in pools and long gentle runs.


From December through to the end of February the water temperature in the rivers rises quickly so the angler can now wade wet and not have to clamber around in waders. As the water temperature rises the insect life gets a big boost and the rivers will come alive with activity, both on top of the surface and below it.

With more insects hatching the fish will spread out further in the river and the food factories will be found in the runs. Mayflies, stoneflies and caddis will all be present if the river is in good order and, with temperatures rising, so will the metabolism of the trout, forcing them to feed more often.

Over these months they will tend to sit in faster flowing water and often, especially in really hot weather, trout will be caught in heavy pocket water which is barren for most of the year.

The summer will also bring more terrestrial insects in the air and invariably insects like beetles and cicadas will end up on the water where trout will feed ferociously on them.

River anglers will be just as successful if they are using large dry flies or nymphing, making the summer months the most enjoyable time to be out on the rivers.

Like the rivers, the water temperatures out on the lakes will also rise rapidly and, during long settled periods of little wind, the layers of water in the lake stratify, separated by a well defined thermocline.

When this happens the smelt school in the cold layer and this is where you find the trout.

Mid summer on the big lakes is where jigging comes into its own and it becomes very easy to target the trout. Just look for the smelt schools which show up on the fish finder.

On the smaller insect-based lakes like Otamangakau where the majority of people fly fish, the insects also become more active with the warmer air temperatures. Damselflies and dragonflies will be in the air hunting other insects and, as the nymphal forms of both species ascend and hatch through the water columns in the lake, trout will once again feed hard on them around the weed banks.

These lakes also have very good cicada and beetle fishing on the surface when conditions are right in the middle of summer. The fishing will generally stay red hot while the insects are very active in the air until the first frosts in March or April.


Once the frosts hit the fishing will tend to slow down. The fish now, though, are in top condition after feeding hard through the summer and are readying themselves for their spawning runs. As the air temperature drops so too does the insect activity, but on many freestone rivers some good mayfly hatches will be encountered.

Rivers like the Mataura in Southland and the Tukituki in Hawke’s Bay are famous for their consistent mayfly hatches over the autumn. Brown trout tend to run to their spawning grounds before the rainbows and in the North Island rivers like the Ngongotaha and the Tongariro will be busy with many anglers specifically targeting these really big, early spawning browns.

By the end of April and into May will see many of the rainbows moving toward their spawning waters and on the big Central North Island lakes these mature rainbows are now congregated around river mouths where they can be targeted by the fly fisherman. When fishing these drop-offs cast a long line and retrieve slowly, working the fly across the bottom.

The runs will be triggered by heavy rain or a sudden drop in barometric pressure. So during fine weather fish the stream mouths, and once the rain arrives move further up the rivers. Timing fishing trips around the weather will produce more fish.

When trout enter the rivers they pretty much stop feeding. They turn dark in colour and as the ova and milt sacs enlarge the gut cavity fills up, but they will still snap at flies aggressively.

Fly patterns change with the conditions so when rivers are clear natural imitations like the hare's ear and the pheasant tail will work, but when there is colour in the river the glo-bugs and egg patterns reign supreme. The secret is to always make sure your flies are visible to the fish so change size, shape and colour according to the water conditions.

If you get into a stack of fish using glo-bugs there will come a time when a particular colour will stop working. By changing the colours of your glo-bugs you can often keep the trout agitated so you keep catching fish.

The secret to nymphing spawning rivers is to make sure your flies are bouncing on the bottom where the trout are lying, so you basically have to make the flies hit the fish on the nose. This is where the Tongariro rig has become so effective – with a heavy front nymph and a light trailing one. Although not so nice to cast, the rig catches plenty of fish.

Understanding and observing fish behaviour when the waterways are in different states will help you in your quest to become a versatile and competent angler. Putting yourself in different situations and environments will go a long way to seeing you catching fish where others cannot.

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