When I was a boy I couldn’t understand why the salmon swam upstream only to die and gather pale and flaking in eddies along the banks. I built a dam of rocks and branches one spring reasoning the fish wouldn’t die if they couldn’t make it to the ponds. I called, “Turn back! Turn back!” all day as the salmon beat their flashing bodies against my dam, their strength waning with the light until they floated limp and belly-up back downstream, and I was left with the twilight and my deepening pool of clean water, nothing but small sticks washing up along its shore.
This story has a happy ending though. Eventually I learned the salmon's reasons - a girl consenting to step pale-legged from skirt into the pool my dam had made. She said, "It's nice here. The rest of the river stinks like rotting fish."