The first sentence should jump is Catch & Release (catch and release). This practice in itself is a tremendous advance, because some of the fish caught base returns to its original state giving the opportunity to relive the experience for the fisherman or who happens to be the following. There are many more specific considerations that simply getting the hook and put it in the water. You need to consider the possibility that fish will survive. Shorten the time of the fight is essential to keep the energy that the fish needs to return to its pre-capture situation, ensuring their ability to feed and protect as usual to do so.
To return to the water, it is safer to face the current and put in a place where it is not very strong. The idea is to hold in the water until it is oxygenated and is able to swim alone. This means waiting for the fish to own strength and intention swimming out of hand.
There can be someone who is indifferent to meet with a can or container or bag in the river bed. But dirty river goes far beyond the bottles, cans and other trash. If we talk about the idea of going through a place without a trace of that step, then we should think about all the details that we indicate the previous presence of another person. No littering is the basics. Consider details such as cigarette butts, small plastic containers, pieces of nylon. All are small, but the sum in the long run it is not. In fact, not only the visual pollution affects us, but the possibility that the animals come to eat or be affected by these elements.
We must remember that we are invaders in this environment and if we enjoy every day we specialize in impact it as little as possible to keep it.