Re: Winter Smallmouth
I agree on the shade thing. Many of the streams I fish are extremely clear, visibility 6-12 feet. The fish use shade as cover, but if they are actively feeding they don't care whether it's shady or sunny as long as the food is there. And time of day doesn't matter much, either. I'm just as likely to catch a big smallmouth at 1 PM as at dawn, maybe more so.
However, winter fish are a little bit different. If the water is very clear, as it often is during the winter, the fish will often stay on shady banks. Again, it's a cover thing. They don't like to be out in the open and easy to see in the winter. But, if the water has a little color, they will usually move to sunny banks, because their food is also moving to sunny banks where the rocks and bottom and water itself soak up more warmth. On the streams I fish in the winter, I sometimes try to time when I fish a given pool to take advantage of when the sun is on the best parts of the pool.
Winter fishing is very challenging compared to warm weather fishing for stream smallmouth. There are still major unanswered questions about where a lot of the fish actually go in the winter. A recent Missouri tagging study showed that some smallmouth move long distances to certain wintering pools, often passing up a lot of other wintering pools to get to their "favorite". One fish was tagged about ten miles up Courtois Creek, a smallish float stream, and later recovered that winter 35 miles down the Meramec River from the mouth of Courtois Creek, having gone down ten miles of the Courtois, a mile down the Huzzah (passing up a big, deep pool on the Huzzah) and then passing up at least 30 pools that I know are wintering pools on the Meramec to get to the wintering pool where it was caught. Another, tagged in the same area, was caught ten miles UPSTREAM on the Meramec from the mouth of the creek in a big wintering pool.