Once upon a time, Arkansas, Oklahoma, and Missouri had many miles of rivers and streams full of smallmouth bass, walleye, sauger, and other clear water species. Steam boats plied the waters in the wet season. Then someone decided the farmers and settlers needed fewer floods and cheap electric lights. Dams went up. To salvage the ruination of the rivers they stocked trout. To hide the decline of smallmouth, they planted largemouth to boost the natural population. They took northern lake walleye and stocked enough to hide the river strain genetics forever.
Are we not a bit late to worry about "natural" genetics?