Ecologists at the University of Toronto and the Fisheries and Oceans Canada (DFO) are now investigating if and how these ponds’ harsh, polluted environments are selecting for extra-tolerant fish—which might eventually manage to out-compete native species in the nearby Great Lakes. As Nicholas Mandrak, a University of Toronto Scarborough conservation biologist working on the project, puts it: “Are we creating these ‘superinvaders’ that are likely to have incrementally greater impacts in the wild under climate change?”