The stocking truck backs down to the access point on a Tuesday morning in late March, and within minutes the pool is boiling with pale, fin-clipped rainbows milling in the current. A hundred yards upstream, a wild brown trout — three years old, maybe four — holds behind a mid-channel boulder, eating size 18 Blue-Winged Olives with the selectivity that comes from surviving every heron, otter, and drought since it hatched from gravel. Two fish. Same stream. The arguments they provoke have split fly fishing culture for decades.

But the debate most anglers are having — stocked trout are bad, wild trout are sacred — is built on a false binary. The science tells a more complicated and ultimately more useful story, one that distinguishes between very different management tools lumped under the word “stocking” and measures risk in terms of genetics, density, and reproductive contribution rather than moral categories.