Cowpaddock Bay - Arthurs Lake

Summertime is dun time and there's no better place to head than Arthurs Lake. But where? My recommendation, for the shore based angler anyway, is Cowpaddock Bay. Why? Because it is relatively shallow and weedy, it is easily waded and it boasts huge hatches of mayfly duns.

Sevenpound Bay is usually quite good but it is slightly more difficult of access. Jonah Bay can be good, too, but there is much less scope for wading. The hatches at HydroBay and Pumphouse Bay are patchy when levels are moderately high, and that has been the case for several years now. And none of the deeper shores provide red-letter hatch driven dry fly fishing. All up, Cowpaddock Bay is very hard to beat.

Lake levels
For many years the HEC aimed to maintain very low levels of up to 9 metres below full supply, mainly to safeguard against spillage during floods. Following representation from the IFC the flood risk was reassessed and in 1993 the HEC agreed to less severe drawdowns of up to about 4 metres. This means that weed beds in prime bays such as the Cowpaddock now have sufficient water to be fishable throughout the year, a big improvement on seasons past when water was prone to drop right out. Mind you, static levels, even when moderate or high, do not provide optimum conditions. The fish need the seasonal flooding of shorelines if they are to gain access to the bulk diet of worms, grubs and other terrestrial food that so helps them to maintain condition and pile on weight.

In common with other big hydro impoundments, Arthurs does not rise  from minimum operating level to capacity in a single year. The levels wax and wane throughout the season and net gains are made only during very wet years. Under normal circumstances it would take three or four consecutive flood years to reach full supply - an uncommon event indeed.

Arthur's trout
The only non-native fish in Arthur's lake is the brown trout - there are no rainbows, redfin perch, tench or, thank goodness, carp. The trout population is supported entirely by natural recruitment and, because of the abundance of ideal spawning creeks, stocks are incredibly high. In fact, the average catch is 2.4 fish per angler per day which is a much better strike rate than we expect from most highland lakes. In the Western Lakes, for example, average anglers do well to catch a single trout over an entire weekend.

In the 1980s and early 1990s typical fish weighed 0.4 - 1.0 kg, averaging perhaps 0.7 kg or so. However during the big wet which occurred in the mid 1990s the average weight rose considerably, probably to something in excess of 1 kg, and anglers could reasonably expect to catch good numbers of fish in the 1.5 kg class. At this time there were also incidental catches of 2-3 kg fish.

Local guides who use boats, know the choicest areas and are familiar with specialist techniques are still able to put their clients onto fish which are mostly 0.8 - 1.2 kg. Still, it is fair to say that size of the trout has moderated during the last couple of dry years. In the Cowpaddock you will probably catch many smaller fish. Nonetheless, fish in excess of 1 kg are common enough. Often, after a spell of catching modest fish, bigger ones seem to materialise from nowhere and you catch several in quick succession.

Mayflies (insect order Ephemeroptera) are my favourite insects. Like trout (unlike, say, stonefish) they are poetically proportioned. Moreover, they have a fascinating life history.

The mayfly spends about one year as an aquatic nymph, generally feeding on plant matter and residing amongst weeds or beneath rocks. Then the nymph either crawls out of the water or swims to the surface and hatches into a dun (so called because they are quite dull with opaque wings). Duns are a sub-adult (or sub-imago) form which have no parallel in the life cycle of say butterflies and moths. Depending upon species, the dun lives for a few minutes or few days before it sheds its skin and emerges as a sexually mature adult (or imago). This final morph is not entirely unlike the dun, but typically the body is shiny and the wings transparent. Spinners are very short-lived, surviving just long enough to mate and deposit their eggs on the water surface. They can often be seen spinning about in huge swarms along river banks and lake shores - and even well off shore if it is suitably calm.

The dun phases of the highland spinner (Tasmanophlebia lacustris) and especially the Penstock brown (Atalophlebia superba) are revered by fly fishers because they both commonly hatch on the water surface where they provide easy pickings for trout. These duns are frail beasts which tend to linger on the surface while drying out, drifting along oblivious to any danger before finally arriving at the far shore or gathering enough energy to fly away. Both species are prolific at Arthurs.

Incidentally, if you are especially interested in Tasmanian mayflies Dr Ron Thresher presented a comprehensive three-part overview in issues 10, 11 and 12 of FlyLife magazine.

Ideal conditions
Mayfly hatches in Tasmania are primarily triggered by water temperature but are also affected by prevailing weather. At Arthurs Lake suitable conditions are likely to occur from early November through until the end of summer.

Sunny and calm is the cue which tells nymphs to swim to surface. Once in the surface film they must pause while they hatch. So you will often see trout bulging the water as they suck down suspended nymphs, and you can often nail a few such fish even before the hatch proper has begun.

Each dun appears in an instant, "pops" if you like. If things remain warm enough and calm enough for long enough the water surface is suddenly dotted with duns. They sit lazily on the water and, because there is no need for urgency, the trout swim about slowly and methodically mopping up one after another.

Nothing can quite compare to a warm, calm day on Arthurs when dozens of dorsals and tails are slicing up the water around you and the air is alive with the the merry sucking and clopping of feeding trout.

When it's windy
Because the trout feed so spectacularly when things are bright warm and calm it is easy to become dispirited when the wind gets up and the rise suddenly stops. But wind is a fact of life and if you confine your fishing to perfect conditions you probably aren't going to do too much fishing at all.

It pays to remember that the trout will still be cruising about, most probably picking off nymphs that are crawling out from the weeds getting ready for the next lull. They may be difficult to detect but they are there. Also, there will be isolated hatches and rises even in the biggest waves. Never let your guard drop. Scan the water constantly and get used to spotting atypical ripples and splashes with your peripheral vision.

Trout love the security of deeper water, especially when the surrounding flats are relatively shallow, and often a significant number of fish will retreat to the gutters during a lull in the rise. Trout also like cruising the edges of emergent weeds, underwater weed beds and drop-offs. Since water in the Cowpaddock is often difficult to polaroid it goes without saying that local anglers familiar with underwater features have a significant advantage over new comers. Begin "mapping" the water from your first visit. If you strike low water, commit to memory any exposed features. Otherwise just feel your way along.

So, the first secret to success is to wade lots of water casting fast and accurately to any subtle rise. The second tactic is to prospect likely spots as you go. Standing in the one spot casting haphazardly over the same old water while you wait for the breeze to abate is simply not good enough.

What about polaroiding?
Water in the Cowpaddock is rarely transparent and, while you might see some fish (especially those which remain close to the surface between rises) the mottled bottom makes polaroiding very difficult. When the rise is not on you will need to fish blind. Take heart - this is not as bland an exercise as you might think.

(There are places in Arthurs Lake where there are exceptional opportunities for polaroiding but unfortunately most of these are inaccessible unless you have a boat.)

Efficient prospecting and the adoption of English techniques
My mate, Lester Jones, regularly takes big bags from the Cowpaddock even when no one else is getting anything at all. His secret is nothing more than to search efficiently in likely water. He works his way along all the best features, casting a short line (10 - 15 metres) and allowing the fly to rest on the water for no more than five seconds or so at a time. He is also has a canny ability to predict the likely movements of any fish he spots (this comes from experience). When he spots a rise, the fly is there in an instant and if the fish doesn't take within a few seconds, his fly will be somewhere just ahead of where he expects the fish to have gone. Also, Lester casts efficiently, often teasing the dry across the surface before lifting and never making more than one false cast. Despite the frequency of his casts I swear his fly is on the water much longer than most anglers manage. As for flies, he's happy to use a traditional imitative dry when the rise is in full swing but prefers an emerger when searching.

Since the English master John Horsey visited Tasmania early in 1999, blind fishing in Tasmania generally and on Arthurs Lake in particular has undergone a revolution. Strange as it may seem at first, English techniques work on our wild browns just as well as they do on rainbow "stockies'.

The first thing I noted was that John, like Lester, leaves his fly in the one spot for no more than five or ten seconds at a time. Also, like Lester, he tries to cast out to the side rather than straight in front, so that as he moves along the fly is retrieved over new water rather than water that was already covered on the previous cast.

But the English take the whole thing a step further, using a team of three flies, the top dropper being 3 ft from the fly line, the second 5 ft from that and the point fly yet another 5 ft further on - making an overall leader length of 13 ft. For normal boat fishing, you might use a team of wet flies or nymphs but for summertime at the Cowpaddock what you want is three dry flies. Horsey recommends that you use three different flies so that you hedge your bets and so that one or more can act as attractors. His ties have lightly dressed seals-fur bodies and cheap "nasty" hackles. Popular patterns include the English Hopper, Bob's Bits and Carrot Fly. Once treated with floatant they sit in the surface film but never sink.

Think about what the Horsey technique means - six casts or so per minute with three flies covering new water each time. It's just got to be way more efficient than sitting one fly in the one spot. Not only that but, if things are really slow, you can help bring the trout to the surface by retrieving the flies across the surface in short bursts, skipping the flies about and lifting the flies from the water one at a time. You can actually tease fish right up to your legs. Do it - even Lester has noticed a marked improvement in his catch rate!

For more information on English techniques look up Neil Grose's article in Tasmanian Fishing and Boating News No 21 and Rob Sloane's article in FlyLife No 16. Remember, too, that the flies and methods are familiar to the majority of staff at all local tackle shops.

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