Often times, folks coming through Jasper would like to take a fishing excursion. Without spending some time in the area and knowing the "honey holes" there's still plenty of good fishing. Don't worry folks, I wont give up any of the secrets, I'll just cover the obvious.
First and foremost, the one place you can pretty much count on having fish for dinner would be the Platoro. If you look at a map, it's roughly 10 miles up the road (road 250) from Jasper. Taking the Stunner Pass fork to the left, the Platoro can't be missed. As you aproach the Platoro from the road, you will notice a small pond across the street near the rest rooms. This is Mix Lake, where there are plenty of fish. Although these fish can be watched from above, they can be quite hard to catch. Remember that high-altitude lakes tend to be crystal clear and calm. The fish can be very sensitive to heavy line, large hooks and anything outside of the natural environment. Similar to other ponds and lakes in the area, Mix Lake has a ring of shallow around the banks making it hard to cast out to the holes (where the fish are). Sometimes you will score a shallow bite, but less often than a hole. That being said, having a canoe would be the best bet for Mix while fishing from the shore might be better across the street at the Platoro.
I've personally fished the Platoro for several years now. The first few times, I would get skunked about 50 percent of the time. Now that I've figured out the basics, I get at least 1 fish on every trip. Usually between 1 and 10 fish total for the group of 2-3 people. That's pretty good..
I've found that the Platoro has a large availability of Rainbow Trout recent stockers. These will be under 10 inches, but tasty eating no less. Also, fishing from the "boat launch" area has rarely been productive for me. I would keep driving towards the far side of the Platoro until almost to the end. You will notice a steep road that drives down to the bottom of the lake from the main road. I would not suggest driving this road with anything less than a 4x4, I usually put it in 4-low. It's quite safe, only too steep for a car or 2x4. Once you get down to the water, ANYWHERE on the shore in the area will prove well for you. I like to take a bobber/hook rig to soak worms (works the best) and a fly rod to have fun on the surface (works 2nd best). Third choice would be a small chrome spinner using a red tail on the hooks. This will catch trout, plus it's the #1 baid for Kokanee Salmon. Catching Salmon from shore is possible, but much easier from a boat.
That's my personal experience, I'm sure theres plenty more gems others could offer. Please contribute if you can and let us know you your fishing adventures work out!