It should run it's course. Personally if you are out in the middle of nowhere where no one can see what's going on... I would shoot, shovel, and shutup. It sounds like the birds are stressing the weakedend fish further by running them around under water. However in all fairness to the birds, they are doing what they are intended to do -- remove sick and dying fish.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.