All of the administrative troubles paid off though. We caught (on the fly with barbless hooks) and released 19 small-mouth yellowfish. Three days of awesome fishing and beautiful surroundings.
This is what the river looks like in most parts. The water is very clear and the fish spot you easily, so casting upstream, or keeping low is necessary. Sight-casting for yellows is possible, but infuriating. It is terrible to see how your fly is ignored. On the second day I cast my entire flybox at six yellows feeding actively from the surface, but they ignored everything. I am not sure whether they become fixated on certain food type and size (like trout sometimes do)... Although I knew beforehand that more than two-thirds of the yellowfish diet exists of caddis flies at various life stages, I had no success with caddis imitations. All the fish I caught were on imitations of mayfly nymphs.
Smallmouth yellows are a lot like grayling, so they hang at the inflow and exits of pools, or in the eddies behind rocks, or close to the reed-beds, and wait for food to drift to them in the current. Casting to those lies is the most productive strategy.
My friend caught the fish of the day with this one of just over a kilogram.