| Supersized Goldfish Could Become Superinvaders | |
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Credit: Christine Boston/Fisheries and Oceans Canada |
Just west of Toronto last summer, startled biologists counted more than 20,000 goldfish in a single urban stormwater pond the size of two basketball courts. And the fish, probably descended from dumped pets, were not only thriving numerically—some had grown into three-pound behemoths. Cities around North America have increasingly been building such ponds in the past 40 years to capture rain and runoff, and invasive goldfish are flourishing in thousands of them. |
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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?” |
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