Unlocking Diefenbaker Rainbow
Saskatchewan’s largest southern waterbody, Lake Diefenbaker, is known for incredible multi-species angling opportunities with over 23 species lurking in the depths. In fact, it’s the home of world records for rainbow trout and burbot, so it is also known for some massive specimens. Being 225 kilometers long and up to 66 meters (220 feet) deep, it can also be daunting to the average angler. However, by paying attention to structure and food sources, good fishing can be had. The best part is that open water access to cold water species—such as rainbow trout—is available late into the autumn months. As the flowing water and depth make Diefenbaker one of the last lakes to freeze up in Southern Saskatchewan, a fall trip for Diefenbaker Rainbow is an excellent destination fishery.
Where do you find them? Considering that you could launch south of Saskatoon and darn near drive your boat to Alberta in this lake, it is helpful to concentrate your efforts in three areas: rocky shorelines, small bays, and below the spillway.
Open Water Tactics
An effective strategy for these roaming trout is to cover water by trolling. Large sections of rocky shoreline at the intersection of the lake’s two arms is a good place to start. There are many kilometers of boulder spree in 3-7’ of water to be covered. These rocks are well worth your time as they are home to many crayfish and more importantly, schools of young-of-the-year yellow perch and minnows. These forage fish keep the ‘bows close by.
LURE CHOICE
It is important to troll spoons that emulate these fish. Little Cleo spoons you might have in your ice tackle or weighted Mepps spinners are best trolled at 2-2.5 miles per hour. The action of these spoons looks very similar to fleeing juvenile perch. While ice-fishing at night with an underwater camera, I was fortunate enough to see massive whitefish and rainbows chasing these little perch around the bottom. It is amazing how the shape and movement Little Cleo spoons provide while trolling mimics the action of those perch swimming for their lives.
LONG LINE TROLLING
Pulse out your spoon to a good distance from the boat. When you think it’s far enough back, let out more line. The extra line allows the trout that are temporarily spooked out of their lie when the boat moves through the shallow water to slip back into their strike-zone. It also gives outlying trout more time to move in from a distance to investigate the vibration of the lure felt in their lateral lines.
EQUIPMENT CHOICES
An ideal rod is a medium fast action rod around seven foot long, as the parabolic nature of these rods absorb the big headshakes, bulldogging runs, and aerobatics rainbow trout use to avoid capture. It is also a good idea to use a leader of fluorocarbon line as trout can be line shy.
These shallow, rocky shorelines are also home to northern pike and incidental catches are common, so be ready on the rod to set the hook in the side of the mouth to avoid the line-cutting teeth of those pesky pike. The rocky stretches are also the shore fisher’s best bet with many anglers catching big specimens bottom fishing with pickerel rigs tipped with minnows. Please be respectful when accessing these areas as much of the shore is backed onto private land. Seek permission from the landowners prior to going and be sure to stick to roads and trails.
Back Bays
When the South Saskatchewan River valley was flooded during the creation of the lake, the many draws and coulees transformed into deep, narrowing bays. There are a series of them on the northern end of the lake and these bays can be a hotspot for fall rainbow trout.
Like most trout streams in Saskatchewan, the shallow, back end of these bays are rich with swarms of water boatman. This swimming insect buffet is hard to resist for trout. It may also be that the trout are seeking our eggs from fall spawning fish such as cisco, which is perhaps why bottom rigging trout paste into small, fish egg-like balls during the early ice season works well. In any case, it is worth working these bays from a boat or shore. Another strategy is to shore fish the edges of the bay mouths where the steep sandy edges drop to 40 feet deep.
Tailwater Trophies
The outlet side of Gardiner Dam is both the most promising place for massive rainbow trout and the most difficult to access by boat. With the lack of a boat launch, you must be creative to get a boat to water. The big rainbows hold in the tailwaters below the turbines of the hydro-electrical dam as there is a steady supply of stunned or mutilated cisco that met their fate with the turbines. The steady supply of easy pickings keeps the trout in place and grow to huge proportions. Fishing dropshot rigs with cut bait to copy the food source is an effective presentation. Whitefish and burbot will be in line at the buffet, so a multi-species session is a real possibility.
Targeting Diefenbaker rainbow trout in the fall is worth the trip as the salmonids are above average in size and ravenous in October. Their size is due to ample food sources and genetics (see side bar), while their hunger is due to their love of cool water and winter’s approach. The colours are stunning—beautiful dark green backs to match the algae-covered rocks they haunt and deep magenta stripes over flashy silver sides—and these chunky fish make delicious table fare.
Big Lake, Big Fish! A history
Being the largest reservoir in the province, Lake Diefenbaker was created in the 1960s to provide irrigation opportunities for agriculture, limit ice damning in the city of Saskatoon, and to regulate water flow in the Qu’Appelle system. It is also home to the hydroelectric Gardener Dam. As the South Saskatchewan watershed is fed mostly by snowcap melt in the mountains of Alberta and BC, the lake itself can see wild water level fluctuations each year between 3-30 feet! Be careful while trolling the shallow, rocky sections and if you are travelling any great distance to fish here, do your best to inquire locally as to the water conditions.
These productive waters consistently produce trophy species that originally dwelled in the river system as well as huge stocked species, such as rainbow trout. Interestingly, biologists have identified Diefenbaker as one of two confirmed successful spawning lakes for rainbows in Saskatchewan. Undoubtedly due to the abundant food sources and varied habitat, the naturalized trout are also augmented by escaped trout from the fish farm that share these waters. The floating nets occasionally experience breaks—locally referred to as jailbreaks—add thousands of additional trout with the genetics to grow fast and fat are added to the mix. According to the Saskatchewan Stocked Waters Guide from 2020, over 30 000 of each rainbow and brown trout fingerlings were planted in the tailwaters. The opportunity to tussle with one of these footballs is waiting for you.