Finesse Spin Fishing is not just using an ultralight rod and reel. It's how you use them. The average guy can take a spinning rod and reel to a trout stream and catch a few trout here and there. A master will (or at least can) catch more than you would believe possible. Spin fishing for trout in streams is - or at least can be - extremely effective.
When I was a kid, my dad (who was a fly fisherman) told me that spin fishermen would catch bigger fish but fly fishermen would catch more fish. I wanted to catch more fish, so as soon as he thought I was old enough I got a fly rod and, to be honest, I never looked back - at least, not until fairly recently.
My father was wrong. Well, he was half right. Spin fishing for trout will catch larger fish on average than fly fishing. However, if a spin fisherman knows what he is doing, he can also catch more fish than a fly fisherman. It took me a long, long time to discover that, and then a bit longer to actually believe it. Believe it!
The part about the larger fish is easy to accept. The biologists tell us that once trout get over about 13", they become piscavores rather than insectivores. Most of their diet is fish - dace, shiners, chubs, sculpins and smaller trout. If a 15-16" trout mostly eats minnows, pulling a spinner past him is more likely to get a response than drifting a mayfly over his head. Granted, big fish are caught on flies. No one is denying that. However, on average, the guys pulling a spinner or plug past the prime lies are going to catch more of the larger fish than the fly guys will.
Now, here's the part that my father didn't know, and that I didn't know for many, many years. A master spin fisherman will cover a lot more of the stream than a fly fisherman. He will thus show his lure to a lot more fish. Some of the fish will be aggressive and some won't. Some will be hungry and some won't.
Any one fish, if it is hungry, might hit either a fly or a spinner, but if you present your (fly or lure) to more fish, you will find more hungry ones and over the course of a day you will catch more fish. Also, it is generally believed (although not by all) that a spinner or plug (or a streamer, for that matter) can trigger a reaction strike. Trout are territorial, and there is a pecking order. The biggest fish command the best lies. They will chase other fish and sometimes just nip at their tails.
I have been told of trout caught on spinners in clear water, (where the angler had an excellent view of the take) that never bit the spinner as if to eat it but only nipped at the "tail" and ended up getting caught on the treble hooks. I have no idea how common this is but I am convinced that it happens. What doesn't happen is for a fish to chase a mayfly out of its territory nipping at its tail! If it wants to eat it, it eats it. If it doesn't, it just lets if drift by.
I do believe you will catch trout with lures that you could not have caught with flies. Of course, if there is a hatch going on and the fish are keyed on that particular insect, a fly fisherman can catch fish that a spin fisherman couldn't. On some of the most productive streams for spin fishermen, there aren't blanket hatches that turn the trout into selective eaters.
I am surprised to say that in all the years I have been fishing for trout, I do not remember ever seeing a spin fisherman wading. Oh, I've seen lots of guys with spinning rods, but most were just sitting alongside a big pool with their rod propped up on a forked stick.
That's not finesse fishing! The guys who know what finesse spin fishing for trout is all about move - and fairly quickly. As mentioned above, it's all about finding the hungry, aggressive fish. They aren't going to come to you. They will be down among the rocks, by (or under) the logs, under the undercut banks, under low branches - places where they have a place to hide, a place to rest and a supply of food.
The few spin fishermen I've seen who weren't just sitting down would walk along the stream and where there was an opening in the trees and bushes make a few casts, and then go to the next access point.
I live in the east, and the streams are all choked with trees and bushes. Places where you can actually get to the stream to make a few casts tend to be far apart. The good lies are spread out along the stream - so only a few of them can be reached by casting from one of the easy access points. Even when you could reach one, often the angle would be wrong. Thus, if you don't wade, you can't possibly catch most of fish that you could catch if you did wade!
Take a tip from the fly fishermen and wade. Not only that, fish upstream. The fish are less likely to see you. Cast upstream and retrieve your lure downstream faster than the current. Don't be worried that you will be retrieving your lure too fast for the fish to get it. They can swim faster than you can retrieve, and if a fish wants your lure, he'll get it.
Here's a tip that even many fly fishermen don't know: never wade through any water you haven't fished yet. You would be (will be) surprised to find fish right where you would have walked through.