A recent study published in Diversity and Distributions reveals that trout in rivers affected by metal pollution from old mines in the British Isles are genetically isolated from other trout, with reduced diversity and increased vulnerability to future threats. Conducted at 71 sites in Britain and Ireland by researchers from the universities of Exeter and Cardiff, the study discovered that trout in polluted rivers, while appearing healthy, have adapted to the metal pollution, leading to genetic divergence from the wider species. This isolation is exacerbated by physical barriers in rivers. The researchers suggest that reducing mine water runoff and removing physical barriers could help mitigate this genetic isolation.