Goldfish: Pretty Pets or Pernicious Pests?
The introduction of exotic species and their potential to become invasive is one of the leading causes of the declining status of native biodiversity. In addition, costs to the economy from the prevention, control, elimination, and the mitigation of effects of exotic/invasive species, and costs from lost opportunities are estimated to be in the hundreds of billions of dollars per year worldwide. For Canadian freshwater fishes, exotic/invasive species are the second most important cause of extinction or extirpation (after habitat loss and degradation).