The last episode I watched dealt with him fishing a river in Montana (I think) that was killed decades ago by mining operations. Once the operations stopped, conservationists set about to fix what the mining destroyed. They were successful and the entire point of that episode was showing that a dead river can be brought back to life if you stop polluting the sucker and reverse what man did. He mentioned that fact in so many different words time and time again. I'd say he would certainly mention conservation concerns of a river if he's aware of them. The guy is an river environmentalist and he makes no bones about that. If someone knew which river (s) he is fishing, you could determine if there is info he needs to mention in the series and pass it along. Maybe James could help with that. I seriously doubt if Zac would avoid pointing out problems if there are any.