Lake St Clair  - a great fishery - unfished

Greg French takes a look at Lake St Clair and St Clair Lagoon.

Just why the Lake St Clair system has failed to become very popular among anglers is a mystery. It is undoubtedly one of the very best trout fisheries in Tasmania today - and I suspect that it always has been.


A description of the St Clair System

St Clair is entirely within the Cradle Mountain - Lake St Clair (World Heritage) National Park. It is the deepest glacial lake in Australia, sections of the Deep Shore plunging as much as 174 metres, and the water is always crystal clear. The lake is contained between densely forested tiers (Mt Olympus and the Traveller Range) at an altitude of about 737 metres. Vehicular access is limited to the southern end. While there are elaborate visitor facilities at Cynthia Bay, most of the rest of the lake is wilderness. Although St Clair is essentially natural, levels have been manipulated for hydro - electric purposes since 1938. Water can be retained behind the radial gates on the St Clair Weir, backing St Clair Lagoon up into the main lake and thereby raising both waters by as much as three metres. In modern times this has not usually been done unless Lake King William (a huge impoundment just a few kilometres downstream) has been in danger of spilling, and throughout the late 1970's and 1980's, when things were very dry, there was little water manipulation. Since 1994, though, state-wide flooding has meant that St Clair has been kept at capacity until Christmas or later.

The Pumphouse was once used to pump Lake St Clair to unnaturally low levels. Water was discharged into St Clair's Lagoon, from where it flowed down the Derwent, feeding numerous power stations on the way. The purpose of the St Clair Dam, the tiny low-profile weir between the head of St Clair Lagoon and the outflow of Lake St Clair, was to stop the pumped water flushing backing into the main lake. When the St Clair system was so manipulated, the height of the main lake was often significantly lower than the height of the lagoon. However, the pumps are now inoperable. They were last used in 1967 and will not be recommissioned.

Lake St Clair

Not all of the main lake is deep. The Derwent Basis is shallow enough so that from a boat on a bright day you can see most of the bottom. There are also extensive beaches along the southern shore and at the Narcissus end. Other hot spots for trout include the mouths of tributary creeks, the tea-tree marshes adjacent to St Clair Lagoon, and the wind-lanes. This diversity of habitat combined with the crystal clear water and pristine forest setting make for a fishing experience as rewarding as you are likely to find anywhere in Australia.

Facilities and regulations

Since the national park is one of the most popular in Australia (especially among day trippers and bush walkers) the southern end of the lake is intensively managed. Camping is confined to formal sites at Cynthia Bay and is not permitted along the beaches or at St Clair Lagoon. Less formal tent sites can be scouted out at the southern end of the lake at Narcissus. There are small public huts at Narcissus and Echo Point. The boat launching ramp and kiosk are found at Cynthia Bay.

Open camp fires are prohibited at all times of the year.

Since the beginning of the 1997-98 season bait fishing has been formally prohibited. Among other reasons, this regulation has been enforced to reduce the risk of noxious species being transported to the water (remember the carp in Lake Crescent) and in an effort to eliminate the lakeshore litter.

Trout stocks

Trout in Lake St Clair are maintained entirely by natural recruitment, the principal spawning grounds being in the Narcissus and Cuvier rivers. While brown trout dominate, rainbows account for up to 20 % of the annual harvest. Typical fish weigh 0.4-0.8 kg though specimens to 2 kg are reasonably common.


Trolling is extremely productive, especially over the shallower areas of the lake such as the Derwent Basin, Narcissus Bay and Frankland Beaches.  The most popular lures are Tassie Devil Cobras, Spoons and Wonder Wobblers. A few years ago I encouraged several competent friends to try deep trolling (with downriggers and lead core lines) but they reported disappointing results and soon went back to using conventional methods. In hindsight there are a couple of reasons for St Clair trout not to concentrate on feeding deep down. The most obvious is that, unlike the situation in Rotorua, and some impoundments on mainland Australia, the surface water never becomes uncomfortably hot. Also the bait fish in St Clair do not school deep down (as do smelt in many waters in New Zealand and Victoria).


Spinning from the banks results in many fine catches, especially when the weather is dull and windy. The best vantages are Cynthia Bay, the Frankland Beaches, Echo Point and Narcissus. As for lures, it pays to use something with a bit of weight (spoons and cobras are ideal) so that you can cast well out. Remember that rainbows prefer to feed in deeper water, and browns in clear shallow water close to shore can be very spooky. Wading is advantageous in many areas.

Fly Fishing

The ever clear water means that St Clair is perfect for polaroiding. All you need is a bit of sun. For the shore based angler, there is action aplenty over Cynthia Bay, Frankland Beaches and Narcissus Bay. The browns often cruise close but it always pays to wade a bit off shore and look back towards the banks - you are much less likely to spook fish that way. On warm days trout will often be seen leaping out after black spinners. Under these conditions you have to learn to be discerning. Many of these fish are very small and, if you rush towards them too quickly, you are likely to spook other fish nearby. I am not suggesting that you ignore rising fish, just remember to search all the water in between because polaroiding is always going to deliver the best fish and most consistent results. If you have a dinghy or runabout take advantage of the wind-lanes, especially on sunny summer days when the gum beetles are on the wing. This style of fishing in St Clair is truly world class - it would be hard to find more consistent dry fly action of such quality anywhere in Australia. Strong persistent lanes from across the Derwent Basis (especially near the island) and down the main body of lake. Rainbows dominate but you will also find plenty of browns.

Evening rises occur along most shores when things are warm and calm. Use a Royal Wulff until dark and then switch to a Cork Fly or bulky wet. Some of the best action occurs in the Narcissus spit and the lowest few hundred metres of river proper. Here the fishing often continues all night, hook ups coming thick and fast even when the rise appears to have waned or stopped. Traditional wet fly fishing is available only when the lake is artificially high, peaking in the weeks either side of Christmas when the tadpoles are about. There are small flood plains adjacent to the over flow of the Narcissus River, but the very best sport occurs in St Clair Lagoon. 

St Clair Lagoon

At natural low levels, when water is flowing unhindered through the radical gates on the St Clair Weir, the lagoon is quite sperate from the main lake. It is very shallow and at times can be wadded all over. Marshes of one sort or another (tea-tree, strap weed, pin rushes, grass) encircle the lagoon. When major flooding occurs, the marches begin to fill, providing lucrative feeding grounds for brown trout. Even when the radial gates are wide open, the water may rise enough to create good wet-fly conditions but the best conditions arise when water is being stored. At these times the marshes flood way out, doubling the surface area of the lagoon. Super-high levels often make access along the scrubby edges quite awkward but, even when the lagoon is at capacity, keen fly fishers will still find pockets of wade-able water. Try something midway along the eastern and western shores. 

Trout stocks

In most years the trout are similar in size to those in the main lake. However, after successive wet seasons, when the marshes have been full for months at a time, trout in the lagoon really pile on the weight. The average size rose from 0.6-0.7 kg in 1993 to more like 1.2 kg in 1996. The downside on this, of course, is that during the nest dry spell the older fish will not be able to sustain their size and dwell on such hiccups - there will still be plenty of fine fish about.

Lure fishing

The physical nature of the lagoon ensures that almost all devotees are fly fishers. The combination of extremely shallow, gin-clear water and spooky fish means that, at low levels, lure fishers experience limited success. When levels are artificially high, small boats can be taken into the lagoon from the main lake via the Derwent basin and at these times it is possible to successfully drift-spin and even troll. However, most lure enthusiasts still claim to get better results in the main lake.

Tailing fish

Brown trout tail reliably year-round. At low levels they feed mainly on water slaters and snails and can be just as hard to fool as the untouchables at Little Pine. However, when there is water in the marches the fish are likely to be foraging after larger items and can provide action aplenty. St Clair trout like to gorge on worms but this sort of fishing is not a regular event, occurring only when the marshes have re-flooded after several years of exposure. Frogs are a more common feature, especially in October and November, while tadpoles, the real attraction are prominent in the weeks wither side of Christmas.  If the lake has been kept high until tadpole time, falling water serves to concentrate the prey and can result in frenzy feeding on a grand scale.

Rising fish

Dry fly fishing can be a year round event as well. If the weather is calm and mild, midges and black spinners will be hatching by September. By summer you can expect to see rising fish whenever the wind dies. But it is a mistake to rely on rises. Many of these showy trout, especially those in the currents, are relatively small and often quite hard to fool. Polaroiding is the key to consistent success.


When polaroiding it pays to start of with a good buoyant dry fly, say a Red Tag or Black  Spinner on a No 12 or 14 hook. If the fish consistently refuse or ignore the dry, then try an emerger or small nymph.

Trout will always be found along the edges but they are spooky or difficult to locate it is time to search the open flats further out. Waders are essential!

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