I've mentioned this study before and I think it was a university study at some school in Ohio. They stocked a pond with fish and started fishing for them. When the fish was caught it was put into an adjacent pond. They fished the first pond until they couldn't catch anymore. They could not catch the remaining fish in the first pond no matter what, but they could catch the fish in the 2nd pond over and over again. I have got to find that study again. It was fascinating....