The Worm Turns

Greg French takes advantage of rising water levels at Great Lake

Tasmania’s Great Lake (now also recognised by its Aboriginal name yingina) is probably the state’s most volatile fishery, offering vastly differing fishing opportunities according to its slowly fluctuating water levels. Currently, for the first time in decades, the lake is inundating revegetated flats and flushing out a wealth of trout food. Many anglers believe that for the past few years shore-based fishing has been poor, but now the worm turns. FISHING IN THE RAIN Yesterday there was 50 mm of rain. Today it’s still bucketing down. Water runs in torrents down the inflowing gutters, flushes in sheets off broad slopes. I’m wading knee deep, polaroiding towards the shore, though it’s difficult to tell exactly where that is. The lake merges seamlessly into the sodden surrounds — partially drowned grasses and small shrubs. There’s a dense layer of finely crushed flotsam trapped hard against a fringe of juncus (rushes). It might be sitting atop a marsupial lawn, or floating several centimetres above. It’s impossible to tell unless I wade into it, but if I do that I might spook fish mooching underneath. There’s a trout now, creeping out into full view. The tips of its dorsal and tail slice the water surface without creating any rings or ripples whatsoever. It’s so surreal, so captivating, that despite the sound of the rain, the world goes completely silent, cocooning me in the moment. The fish slides back under the flotsam. I watch and wait. Watch and wait. Watch and wait. There it is again, just a couple of rod lengths away, heading slowly towards me or, more accurately, towards a scattering of earthworms, fresh and wriggly but pink and wrinkly. I doubt I will spook the fish — most of the ones I’ve seen today have been utterly at ease in the dull light and heavy rain. Still, out of habit, I take care not to make any sudden movements. With a contorted flick of the rod I land my black Woolly Bugger in its path. The fish doesn’t immediately notice, so I give the fly a twitch. An acceleration, a boil of water, and I set the hook. The fish speeds off into the half-drowned shrubbery, zigzagging the flyline around stems and sticks and juncus, making its own geometric string art. Then the line suddenly stops peeling. I begin untangling it from the bushes and, of course, when I reach the end, the fish is no longer there. Nor the fly. Oh well, in this habitat a few break offs are inevitable. THE FISH Great Lake contains wild brown trout and rainbow trout, but the browns dominate in the flooded shallows. Most weigh 0.9 to 1.2 kg, though plenty attain 1.5 kg. In the coming months, as they gorge on worms, they’ll pile on weight and grow even bigger. LAKE DYNAMICS In Tasmania’s pre-industrial period, the natural Great Lake was by far our biggest inland water, a high-country gem located a little under 1019 m above sea level. It was shallow and weedy, but not hugely different in size and shape to the impoundment you see today. The storage capacity of the natural lake was raised in 1915–16, and again in 1922, 1967 and 1982, giving the modern impoundment a full-supply level of 1039.37 m and a theoretical operational range of more than 20 m. In practice, however, the extra capacity of the 1982 dam has hardly ever been used. Even at its highest-ever level, achieved in October 1997, the lake never exceeded 1035.5 m, about 3.9 m below full supply. Water enters the lake via a multitude of small natural creeks, and a couple of large artificial diversions. The most important of the diversions is Liawenee Canal, which redirects the headwaters of the River Ouse. The second most important is the Tods Corner pipeline, which carries water pumped up from Arthurs Lake. On any typical day, about one third of all Hydro Tasmania’s water is stockpiled in Great Lake. Hydro power is used in Tasmania and also exported interstate via the Basslink cable. Mid-winter sees high demand due to household heating, and Great Lake usually drops to its lowest level for the year. The water begins rising again after heavy rain in late winter and throughout spring, and usually reaches its highest level for the year sometime between late October and early December. Then rainfall eases, power is exported interstate for summertime air conditioning, and the lake begins to fall. Net gains and losses from one twelve-month period to the next are incremental. These days, power consumption is so high that the lake is often very low, and the shoreline is usually a barren expanse of wave-washed rock and exposed clay, with some pockets of black mud in the most sheltered bays. It takes several years of well-above- average rain for the lake to rise over the barren ground and start to inundate vast areas of terrestrial regrowth. The last time this happened was from late 1995 to October 1997. Afterwards it fell again, reaching an all-time low in 2009. Then it made modest net gains for a few years, before falling to another nadir in 2017. Since 2017, however, Tasmania has enjoyed a succession of wet years, culminating in the super-sodden spring of 2021. At the time of writing (early December 2021) the lake was about 10.6 m below capacity, a level not seen since 1995, and the water was continuing to rise steadily. BEST BAYS Great Lake is a vast sheet of water and deciding where to go can be a daunting proposition for newcomers, especially for those more familiar with stream fishing. Really though, it’s pretty easy to narrow things down. Early in the high-water cycle, you want to head to the most sheltered bays — Tods Corner, Cramps Bay, Haddens Bay, Elizabeth Bay. Compared to the rest of the lake, these areas are subject to less wave action and less erosion, and terrestrial regrowth tends to be quite extensive and relatively lush. As the lake continues to rise, the western shore of the main lake will hit its stride, especially Christmas Bay, Boundary Bay, Duck Point Bay and Brandum Bay. If the lake gets really high, you can add Halfmoon Bay to the list. BEST MICROHABITATS By October 2021 the water had flooded the barren clay and black mud in the prime bays and was just starting to creep into the sweet spots. Still, these were early days, and even as the water kept rising throughout November, much of the shoreline remained sub-optimal. I had to keep reminding myself to look for substrate which, until a few weeks beforehand, had been good terrestrial worm habitat. Steep banks were next to useless. They had eroded back to rock and clay, and even a big rise in water level didn’t spread out over much new ground. Flats were obviously key, but it turned out that some of these didn’t carry many fish either. I quickly learned not to waste time blind-flogging my way along areas of exposed clay and silt, or even rocky flats with sparse shrubbery. What I needed were flat foreshores where the terrestrial vegetation was rooted in at least a modest layer of topsoil. And this meant trudging hundreds of metres between likely microhabitats. In the pouring rain the most reliable and easily recognised hotspots were where small gutters entered the lake. Invariably these inflows conveyed hundreds of worms, which had been flushed off adjacent land and spat out over little deltas. The only problem was that each gutter-mouth only held a few trout. The fish were keen, but if I didn’t have any other tricks up my sleeve I soon ran out of sport. Creeks aside, I learned to look for juncus marshes, marsupial lawns, and places where emergent shrubs were anchored to dirt rather than clay or rock. Even then, I had to narrow my focus further. With all the rain we’d had, many uniformly flat expanses had been sodden for weeks or months before the lake encroached upon them, and the worms were long gone. Lumpy ground was much better, presumably because the worms had been able to take refuge in the higher, better-drained humps of vegetated soil. Even in the most likely water, I learned to start off bold, and to slow down only when I started seeing or spooking fish. The main thing newcomers tend to forget, especially if they are used to fishing other lakes where the water rises more quickly, is that Great Lake’s worm feeders are generally only found in the extreme margins. Anywhere more than knee deep will have been inundated for so long that there probably won’t be any worms left at all. FLIES When the worms are alive and wriggly, I find almost any wet fly effective. Woolly Buggers and Mrs Simpsons are popular, and slow stripping and twitching can work a treat. The main thing is to select a fly that doesn’t plonk down too hard or continually snag on the substrate. When water levels stabilise, and most of the remaining worms are dead, the trout stop charging towards your fly, and the takes become much more subtle. Worms have a half-life to rival uranium, and long-dead worms, while looking reasonably normal, often disintegrate on contact. Trout overcome this problem by stopping beside them and hoovering them up. If you strip your fly, you just pull it out of the fish’s mouth. Blind flogging is useless. The secret is careful polaroiding and delicate presentation. You can still be surprisingly successful with nondescript flies, but I usually transition to worm imitations. My favourite patterns involve tying a 50 mm piece of pink or light-brown suede-chenille to a #10 hook, perhaps with a few twists of purple or dark-brown suede-chenille in the middle to represent an egg case. I cast this fly half a metre or so in front of the fish, and wait for it to be completely inhaled before striking. On dull, wet days, the trout can be hard to spot and timing the strike can be difficult. In your favour, though, is the fact that you are often fishing amongst emergent vegetation where the riffling effect of the wind is minimised and the shadows reduce glare. Happily, you can also enjoy fishing for worm feeders in bright sunshine. Seriously, if the worms are there, the trout will be too, mooching about in the extreme shallows in the middle of the day under a big blue sky. GEAR Because I spend a lot of my time steering fish away from drowned bushes, even stopping them dead in their tracks, I prefer to use a rod with a bit of grunt. My all-purpose 6-weight is perfect, though my friends seem to cope well enough with their beloved 5-weight rods. Amongst flooded bushes your casts are going to be close, often within a rod length. Short leaders — three metres or less — make it easy to control the fly and help prevent entanglement in the scrub. My go-to tippet is quite heavy — 6 lb Maxima — but if I’m fishing where the snags are particularly dense, or the trout particularly big and strong, I’ll happily ramp up to 8 lb. The fish don’t usually care one way or the other. 2022 INTO 2023 By December 2021 Great Lake had been rising every day for months, and it seemed likely that the water would continue to rise throughout early summer. Because of La Niña, this coming summer may be relatively cool, and demand for power relatively weak, meaning that the lake might not fall as much as it usually does in the lead up to winter. If the current La Niña cycle continues beyond that, spring 2022 could well be better than spring 2021, perhaps even as good as it was way back in spring 1996. Back then, the lake crept up over flat land where the vegetation was chest high, the soil deep and the worms super-abundant. Back then, the trout got as fat as tadpoles, and when you spooked them it was all they could do to waddle out of your way. Hell it was fun. If La Niña extends into 2023, who knows, the lake might actually start inundating ground that has never before been flooded. Now that will be something — I can hardly wait.

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