Zebra mussels have already wreaked havoc in the Great Lakes, altering ecosystems and the food chain, and damaging water pipes in municipal water systems, power plants and other industrial sites. Now the invasive species has spread — or been carried — to the east and is at the edge of New Brunswick. Zebra mussels have been discovered in the St. John River watershed, according to the New Brunswick Invasive Species Council. "We are saddened to share that an established zebra mussel population has been discovered in Lac Témiscouata, just across the border into Quebec," the council announced on its website Thursday.