Here in Holland we are almost out of real traout rivers. What we catch on these rivers is mostly catch and release.There are also two big lakes with rainbow and brown trout. On one of them there is only catch and release and on the other you can take ,limited, fish. I prefer catch and release, because there are not enough places where you can catch trout. Maybe when it is more like in other countries (good rivers and trout lakes)I think I would take now and then the fish home.
I know that in Belgium you can buy a no kill card which gives you the possibility to fish on more rivers (Ardennes).