..studies registered in Montana, USA, and performed on large areas, observed that wild fish is able to spawn and survive far better than stocked one. Local populations are able to re-fill rivers once they are left to thrive. Obviously in the Montana case there is a perspective to take into account: large and unspoiled areas, with good quality untamed waters, rich in macro benthos and far from pollution agents. Additional studies to point a significant negative impact report that stocking may have. Catch and release is a great opportunity but it ought to be combined with monitorin and protecting the environment that allows the ecosystem to sustain itself. A river full stocked with fish, but without ideal biological conditions and not enough nourishment for all the creatures that live in, is no investment for the future.