Our Man In Canada
January 3rd, 2000

Saskatchewan's Inland Sea
Lake Diefenbaker

Chris Marshall

By Chris Marshall from conversations with Bob Sheedy
Bob Sheedy Photos

I've never even seen Lake Diefenbaker, let alone fished it. But 39 years ago I remember fishing in the South Saskatchewan River close to the bridge where Highway #4 crosses it just north of Stewart Valley. I was newly arrived from England and used the float gear I'd brought with me to fish a worm in the streamy water. All I caught were suckers, but to me they were a new and exotic species and, therefore, a delight.

Float Tube and Mothership at Sunset

Today, those stony rapids are long gone, drowned by the water of Lake Diefenbaker, a huge im-poundment in southern Saskatchewan. It was completed in 1967 by building two dams - one on the South Saskatchewan River (at 5,000 metres long and 64 metres tall, one of the largest earthfill dams in the world), and one on the much smaller Qu'Appelle River 45 kilometers to the south-east. The result is a long, thin lake winding up the course of the South Saskatchewan River valley for 225 kilometers, with scores of flooded coulees indenting the banks. That translates into nearly 800 kilometers of shoreline. It's perfect habitat for Saskatchewan's two principal sport fish - walleye and pike. And these are what Lake Diefenbaker is primarily known for: it's a haven for hardware chuckers. But that same undulating shoreline and the cool (16%-20% Celsius), clear water are also the perfect recipe for trout. These, and schools of oversize native goldeyes, have begun to attract fly fishers in increasing numbers. One of these, Bob Sheedy, who has fly fished the lake for several years, is the primary and immediate source of the information which follows.


The trout fishery on Lake Diefenbaker has always been incidental to the walleye fishery. In fact, its biggest boost happened a few years ago when a controversial court ruling required a major trout farm on the lake to release its entire stock of rainbows. Since then, the stocks of rainbows have been augmented by a steady stream of escapees from other hatcheries and from a modest, but growing, stocking programme by the provincial government. Today, fly fishers regularly take rainbows in excess of 20 inches, and last year a 27 pound specimen was landed by an angler trolling for walleye.

But not all the rainbows come from hatcheries. As the South Saskatchewan River is fed by the Oldman and Bow Rivers, it's inevitable that a number of rainbows and browns will drop downstream and take up residence in the forage-rich, cool, clear waters of the lake. The browns are not numerous, but they're big - sometimes very big. There's a story of a 37 pound monster being killed by a spear gun in 1997. The lake also holds lake trout, but these are less likely to feed on or close to the surface as rainbows and browns do. Therefore, they are only incidental targets for fly fishers.


Goldeye The first fish I caught in Canada was a goldeye, back in 1960 on the North Saskatchewan River in Saskatoon. It took a grasshopper which I fished with float gear in the streamy water below a dam on the western outskirts of the city. As a newcomer to Canada, having arrived from England only days before, I found it an exotic catch. However, I suspect that most Canadian anglers who live outside the prairie provinces would feel the same way. Not many fly fishers have ever deliberately fished for goldeye, or even ever seen one.

Yet the goldeye is a perfect fly fishers' fish. It rises freely to dry flies and hits streamers and bucktails with savage enthusiasm. It tailwalks readily when hooked and is far less easily spooked than trout. On Lake Diefenbaker, the average size is around 12 inches, but specimens can hit 20 inches plus.

Exploring a Conola Fringed Coulee

Locating The fish

Although Lake Diefenbaker is huge, finding the fish is not difficult. Much of the main shoreline shelves steeply into deep water and provides little in the way of fish-attracting structure. This means that the highest concentrations of both trout and goldeye occur in and close to the narrow bays created by the flooded coulees. It is here that most of the bars, ledges, weed beds, and rocky points on the lake are found. Shoals of emerald hiners and other forage fish live in and around the cover provided by these structures, and that's where the trout and goldeye hunt them.

Lake Diefenbaker

Water levels are also a major factor in determining where fish, particularly rainbows, locate. Levels are allowed to rise in June, until they stabilise towards the end of the month. As the water rises, it floods the bankside vegetation, much of it dense swathes of yellow canola overflowing from adjacent fields. Trout and goldeye, forage in pods, driving baitfish right into the submerged vegetation. Similar action can be found off the points of the coulees where baitfish also congregate.

Nice Rainbow In the fall, as the water cools, baitfish seek out pockets where sun-warmed shoreline structure, especially rocks, raises the water temperature. Opportunistic rainbows make the most of this. The rock-lined edge of the embankment of the Gardiner Dam, which faces south-east, is one of the top hot spots. ~ Chris Marshall

Concluded next time!

Winter Issue
We thank the Canadian Fly Fisher for re-print permission!

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