Fishing to Finicky Autumn Trout on the Goulburn

While not a very concise title it is one that will grab the attention of many of you, my fellow Goulburn River fly fishers. Whether you have twenty years of experience up on me, or are just beginning to fish this river, this short essay is worth reading if you wish to improve your catch rate at this fabulous time of year.

The Weather and River Levels

Autumn in the Goulburn valley doesn't really start until mid-April despite the calendar's listing of March 1st. While the weather does noticeably cool down through March and we see a return of 20 something degree average days and colder nights, it is not until around Easter time that we start getting the weather that autumn is famous for. Foggy mornings then start to become the norm. Fog that breaks sometime in the early to mid-morning to reveal a blue-sky day. This is the first significant notice that autumn is here and that the hatches are but a matter of days away.

Within a few weeks we usually get our first break in the weather. By break we mean at least a full day's rain but usually two to four. This then sees a decrease in irrigation releases in the Goulburn and increase in hatch activity. This decrease is usually from the 3,000-4,000 Meg/day mark to about 1,000-2,500. A few more frosts will then start to appear with most mornings seeing the grass snap under foot and the car's windscreen coated in a solid mass of ice. This is our favorite period with windless, blue-sky days dominating the weeks courtesy of ultra-slow moving high-pressure systems. The river will all the while be dropping slightly to somewhere in the 1,000-2,000 Meg/day.

* the Goulburn at 130 Meg in the top frame and 4,000 Meg in the bottom.

This happens about the end of April and continues through May for about three to four weeks on average and is a time of great excitement for the fly fisher. The yearly irrigation season closes in the first week of May and the river drops away to a trickle 130 - 500 Meg/day and the procession of fine days seems to be endless. The fishing at these times is challenging but nevertheless rewarding with the chance of a large brown on the dry fly right up to end the season.

Sometime towards or during early June the weather takes a turn for the worse and we start to get more consistent rain events along with heavy fogs that do not lift until the afternoon, if they lift at all. The hatches taper off although a number of small blue wing olive mayflies and midges will continue through the winter months. But this is beside the point as on the Monday night Queen's Birthday weekend, the season shuts as the browns of Victoria are left in peace to spawn.

The Hatches

There is a lot of excitement in our area at this time of year. Hatches of aquatic insects again begin to dominate the fly fisher's mind as opposed to the falls of terrestrials so heralded during the hot months of summer. Beetles, Ants and Hoppers are replaced with emergences of blue wing olives, midges and falls of spinners. While the much loved cricket breaks this trend and offers the chance to continue fishing a larger terrestrial, there is a definite shift in focus from falls to hatches.

The Midges

These little guys are my personal favorite. Not because they are the prettiest or produce the best response from the fish, but because they are the most consistent hatcher. The river can appear to be a desert, totally devoid of any mayfly or caddis activity but you can always rely on the omni-present midge to make an appearance at some stage during the day, if not in waves through the entire day!

Midges have what as known as a complete metamorphosis or lifecycle. They go from egg to larva to pupae to adult as opposed to mayflies which go from egg to nymph and then straight to winged adult. While all stages of their lifecycle are important to the trout fisherman it is really the pupal and adult stages as well as the time in between that is most important to us on the Goulburn. While I am sure that the larval stage is worth imitating in local rivers, not having the luxury of killing fish I cannot offer any significant insights into their prominence at this point in time. Most of my stomach sampling which is via a pump that gently flushes the upper digestive tract usually reveals more advanced pupa than larvae as would be expected during the hatch. Larva are more likely to be drifting and therefore eaten during the invertebrate (read non-hatching drift) rather than at peak hatch times.

The pupa can be represented by a large number of realistic patterns. You can spend hours perfecting them, even painting the cheeks on them with model airplane paint, but in my experience on local waters this is overkill. The humble brassie will work more often than not when the fish are focused on these tiny insects. These flies are simple to tie and will last forever! They are merely copper wire wrapped around the hook and sometimes a tiny bit of dubbing is added at the head but that is all. Nothing to come undone or fray, just an effective and durable fly pattern. They should be fished dead drift below a small dry or on their own with careful attention paid to the leader for any sign of movement, as fish can inspect, take and reject these flies in an instant.

The Emerger/Adult

Again there are a number of patterns tied to represent this stage of the hatch but there is one that stands above the rest. The Griffith's Gnat or Goulburn Griffith's is the fly of choice. Again it is simple to tie and is extremely durable and most importantly can imitate a couple of stages of the hatch.

The Griffth's Gnat is first choice for us when emerging midges are on the menu. It often will work as is, palmered hackle causing it to ride high on the water's surface, but more often than a visit to the hairdressers is in order. Using your scissors to trim the hackle from beneath the fly so that it sits flush in the film. Sometimes you will have to trim most of the hackle away to get a take from a particularly fussy brown.

If there is one thing to remember about fishing this hatch at this time of year, it is this. The river is running very slowly and the fish can easily hold station just beneath the water's surface, which is vital to know as a fly fisher. This means that the window through which such a trout sees is extremely small and the fly must land in a lane only a few inches wide at most. Too often I have seen the most experienced of fly fishers turning to the fly box too soon, before the trout has even got to see the fly properly. I cannot remember how many times I had sworn that the fish had seen the fly and let it go by only to have the fish take it fifteen drifts later. Only change flies after a clear refusal usually noticed by a distinct boil or swirl.

The adult midge while looking nothing like a Griffith's Gnat is effectively imitated by this pattern. Wrongly identified as only a 'balling midge' imitation here in Australia, it gives great results when fishing the general hatch of adults. These need to be the smallest of fly patterns in the #18-20 hook sizes as a minimum. Sometimes even smaller. Again presentations need to be dead drifted over a rising fish on long fine tippets and the approach is most important.

One thing worthy of mention is in regards to the Goulburn Griffith's. The addition of the tiny flashy 'tails' to the popular Griffith's Gnat was a stroke of genius by whomever it was that first did it. The added flash certainly adds something to the fly and it is very effective during the heaviest of hatches of midges. The flash no doubt helping to make it that little bit more noticeable amongst the large number of naturals.

Mayflies

In general we can narrow it down to a few species only. We have an emergence of the reliable rusty duns (Austrophlebioides), the true blue wing olives (still awaiting identification) and the tiny olives (Baetidae). While each is important at various times of the season we can be thankful that large hatches of any of these species do not generally overlap and that we can concentrate on the one species at any one time.

Rusty Duns

These insects hatch from late October throughout the season ending sometime around late April. They are prominent due to their distinct coloring (rusty coloured body and slate grey wing) and their unique body shape. They have a fat, stubby looking body as opposed to a long, tapering, thin, even more elegant mayfly body. The abdomen is fairly chunky along its entire length.

These insects are of importance up until about Easter or a week either side depending on the season. They should be imitated by using the rusty tailrace dun and as they are a strong emerger it is the dun stage that receives the most attention from the trout, and consequently from us, the trout anglers. They are prolific in areas that have a gravel bottom and hence are found in large numbers from Thornton downstream, where the river is predominantly a rock bed. They are particularly abundant in the Breakaway. No special techniques are required other than a drag free drift.

Blue Wing Olive

It's funny that so much of what is only being discovered in Australia has been well documented overseas, particularly in the USA. The blue wing olive is a classic example of this. For years the tiny olive duns that have traditionally appeared in late autumn were thought to be of the same family as these, the larger #16 blue wing olives that hatch on and off through the season, especially early autumn. While there was little to doubt about this anecdotal evidence it has recently been brought to our attention that the two insects are not even members of the same families.

The blue wing olive is a slow emerger. While it generally makes it to the surface relatively quickly after starting its ascent, it often sits on the water's surface for some waiting for its wings to fully extend. As such it is particularly vulnerable at this late stage in the emerging process and an olive parachute with the wing cut away is a great pattern to fish at these times.

Popular literature suggests that the nymphs become active up to an hour before emergence and so a nymph can be fished well before the hatch and bring often great success. Often the angler has little idea that they caught fish in the early phases of the hatch. While getting to know the daily timing of the hatch and tying precise imitations of the nymphs will result in an increased hook up rate, a #16 Pheasant Tail Nymph will often do the trick.

We have found that these duns will often hatch in the mornings between 10am - 1pm with the odd sprinkling through the late afternoon. The spinner of this dun is yet to be identified by us in any numbers and so we can only speculate that it is not as important as some of the others that we see.

The Tiny Olive

Baetidae is the family that fly fishers believed that both this tiny olive and the larger blue winged olive belonged to. These mayfly are tiny with sizes 18-22 the average. They don't appear in any numbers until the weather gets cooler and the river drops below the 1,000 Meg/day mark.
This particular mayfly can hatch in extraordinarily large numbers. Hatches can be so huge that it is hard to see a square metre of water that doesn't have a few dozen of these critters floating on the surface. They can hatch at any time of the day although we see them in larger numbers from 12 - 4pm and often throughout the day in the worst possible weather.

These T.O.s favour a weedy bottom and hence we find them most prolific in the slower sections above Thornton where a weedy, silty bottom is common. The nymphs are quite good swimmers and they waste little time in getting to the surface. However, once there, they often drift for prolonged periods before emerging into the sub-imago (dun). As a result a tiny unweighted pheasant tail nymph fished on a greased leader in the film is often deadly at these times.

Dun patterns should be tiny with a fine #18-20 parachute or no hackle the usual imitation . Rises will often be frantic yet deliberate if you know what I mean. By that I mean that you may have a fish sticking the tip of his nose out every few seconds as literally dozens of naturals drift over it every minute. When this is happening you have one advantage in that the fish is usually so pre-occupied with the hatch that you can get amazingly close to it. Sometimes up to a couple of rod lengths. Trying to work out the rhythm or timing of the fish's rises is as important as using the correct pattern. We would recommend that the experienced fly fisher use parachute tie most of the time switching to no hackle duns if you get a clear refusal in the slower water.

The spinners of this mayfly can be important to us as fly fishers. Morning to lunch time flights and falls are common and imitations should be tied in sizes 18-22. I like a Tiemco 100 Hook, 8/0 rust brown thread, with dun coloured microfibbet tails x3, ginger dubbing that is so sparse that it barely disguises the thread, dubbed up to a spent wing of a few strands of polypropylene tied at right angles to the hook in the horizontal plane, as most spent's are tied. A slightly plumper thorax of ginger dubbing finishes the fly off. Remember that size is the most important factor here.

Techniques

There are a few special techniques that will help you through this often-tough time of the year. While to some degree the following techniques are standard operating procedure to the more experienced fly fishers out there, for many the explanations will just make things that much easier.

Wading

One of the great things about fishing at this time of the year is that you are generally able to wade across the full river course. This means no gravel bar, run, or even pool is inaccessible. However there are a couple of things that must be taken into consideration.

The water is very low and slow flowing. You must wade as slowly as you can or you will send ripples/waves up the pool. While at other times of year you can get away with a little bit of carelessness it is not the case now. Often it only takes the spooking of one fish along the edges or in the tail to ruin the entire pool. It is a real let down to see a large bow wave running up the pool and then several others joining it as it moves up and away from you.

The second thing is to make sure that you do not clunk the rocks along the bottom. Remove any cleats/studs from your wading boots as the scratching will spook the fish. Move one foot forward slowly and get it planted and your weight balanced before slowly moving the other foot up to it. You cannot afford to spook the fish before even getting a fly to it or you will definitely have a very tough time.

Presentations

While this should speak for itself a few words are needed. This is not the time for leaders that puddle. You want a 12 foot leader made up of about 4 feet of heavy butt followed by a steep, short taper down to a 6-7X tippet of around 4 feet in length. As most of the water is very smooth the focus is on accurate, mostly straight-line casts. Sometimes a wiggle cast may be necessary to get some slack in the line but extravagant reach mends and line mending in general is more often than not, unnecessary.

If a fish is found to be rising you should endeavor to get as close as is possible without spooking it. The ideal position is downstream of the fish and off to the side so that any presentations result in most of the leader; and more importantly, all of the line, landing well away from the fish. Often many successive casts will need to be made in order to get the right drift at the right time. As a result casting from directly downstream of the fish and laying the leader over it will result in the fish vacating its feeding lie post-haste.

Sections of River

The Goulburn is river of many moods. Well know this as the levels can see it vary greatly from one day to the next. But there is another factor that you need to consider when chasing these autumn hatches and that is the type of streambed.

Different insects have evolved around the differing niches found in the aquatic world beneath the Goulburn's surface. As discussed earlier the various mayfly we mentioned all prefer different types of structure. For ease of this explanation we will break the river up into two distinct parts. Upstream of Thornton to Eildon Pondage and between Thornton and the Breakaway Bridge. These are the areas that we concentrate our efforts on.

Firstly the area upstream of Thornton and our shop. The river begins to change its composition the further upstream from Thornton that we go. It becomes a more stable bed of silt and weed with much less gravel except for on the corners or bends in the river. This area is prime for midges who love to burrow into the mud. Huge populations of midges can be found in this section and we regularly encounter fish feeding on midges in this area.

Large weedbeds can also be found and these are home to the olives that we love so much. The very biggest of these hatches happen in this section of the river with the largest, most stable weed beds found here. Due to the make up of the river in this section many of the weed beds are under water the entire season, despite the dramatic decrease in water levels through the winter months. As a result there is a very healthy population of aquatic insects to be found at any time.

The area below Thornton is renowned for its mayfly and caddisfly hatches. A mostly gravel bed, with large weed beds in parts, contributes to a very healthy environment for these insects. The rusty tailrace dun and kossie dun are found in particularly large numbers in this part of the river. This section has some major gravel turn over in normal years thanks to large summer releases of 6,000-10,000 Meg/day. This movement of gravel that is noticeable to many by the reshaping of pools and gravel bars is a healthy factor when looking at mayfly/caddisfly populations. It is also something that is happening no way near as often as it should thanks to controlled irrigation releases and the lack of rainfall in recent years. In 1993 for instance we had releases of over 40,000 Megalitres per day as the water managers tried to compensate for a full lake. This moved around huge amounts of gravel up to 500 metres in places. Such an event is long overdue now.

Caddises like the fastest of water and this section of the river is often narrower with a steeper gradient resulting in faster water flows. This highly oxygenated section often has very large caddisfly hatches during the middle of spring through to mid autumn.

So by understanding this we can target certain areas if chasing a particular type of hatch or at the very least we can be prepared when fishing the two sections with some understanding of the flies and therefore tactics needed for success. While there are always exceptions to the rules in nature, this basic overview should hold you in good stead.

Anomalies: Low lake

Over the past few seasons the lower lake has seen a decline in the quality of the olive hatches with warmer water temperatures restricting their numbers. While the flip side is a huge increase in spring hatches with rusty duns and caddis hatches the like we have never before seen. We expect that as the lake fills again we should see a return of the May olive fishing that we remember so well.

As a result the better olive hatches are coming off towards the end of the season i.e. late May and into June. These hatches are continuing right through the winter months and tapering off towards the end of October.

Conclusion

When you are next confronted by the Goulburn post-Easter consider the importance of what has just been said. Use this information to have a selection of thoughtfully chosen flies and make sure that your leader and tippet is of sufficient length and strength. Think about where you will be going to fish and which hatch is more likely to be occurring and then make sure you go slow. Wade carefully, stop every so often and just watch. Catching fish at this time of year can be very difficult but if you are able to put this information to use you should be able to achieve success and gain insights into this beautiful, sometimes complicated river.