I have caught whitefish in the Tobin area so they must be in other parts of the river.
Here is a partial list of fish species in the river walleye, sauger, yellow perch, northern pike, lake whitefish, mooneye, goldeye, white sucker, longnose sucker, shorthead redhorse, burbot, Rainbow trout, brown trout, and lake sturgeon. In 2008 reproducing Prussian carp were found in the Red Deer River drainage basin which flows into the south Saskachewan River so these may eventually end up in the north sask..
I have caught a lot of these species but so far no Sturgeon or Brown trout.