Risks of mining to salmonid-bearing watersheds
Mining provides resources for people, but often harms ecosystems including those supporting Pacific salmon, trout, and char. We review relevant aspects of mining operations, describe the ecology of salmonid-bearing watersheds in northwestern North America, and compile the impacts of metal and coal extraction on salmonids and their habitat. Our new synthesis reveals that this region contains over 14,000 mines, past and present, ranging in size from small placer operations to mega-projects that annually mine over 118 million tonnes of earth. Despite impact assessments that are intended to inform mitigation and regulation, mines continue to harm salmonid-bearing watersheds via exposure to toxic contaminants, permanent burial of stream channels, and alteration of flow regimes. We provide cross-cutting recommendations intended to improve the scientific foundation for mining policy and impact assessment methods by more accurately accounting for the diversity of mining impact pathways, incorporating ecological uncertainty, and maintaining watershed processes that benefit salmonids.