When I went river fishing, we used to keep the fish alive in a keep net, and put them back in the river to swim off as we were leaving. You wouldn't want to eat

When I went river fishing, we used to keep the fish alive in a keep net, and put them back in the river to swim off as we were leaving. You wouldn't want to eat the fish from the river closest to where I grew up. On the other hand, we did use to keep and eat the fish we caught in the sea, and seeing the fish die wasn't very pleasant. I just want to emphasise that it's optional.