I would like to add a few words. Just because an angler releases his fish doesn't mean that hooking injuries causing infection won't kill that trout forty-eight hours later. So, the easiest way to reduce the number of trout rolling lifeless along the bottom of the pools, is to be moderate in our fishing. We can practice personal catch-and-release limits.
It is not necessary to catch thirty or more trout a day, and a large number of fish landed doesn't necessarily indicate the practices of a skilled fisherman... but it suggests a fish hawg. Now, Dante put fish hawgs in the Third Circle of Hell:
In the third circle, you find yourself amidst eternal rain, maledict, cold, and heavy. The gluttons are punished here, lying in the filthy mixture of shadows and of putrid water. Because you consumed in excess, you meet your fate beneath the cold, dirty rain, amidst the other souls that there lay unhappily in the stinking mud.
So, as a part of our fishing we can adopt the adage "Limit your catch, don't catch your limit."