Sep 12, 2007 — This month, biologists in New York and Vermont are spreading a chemical in a half-dozen rivers and deltas near the shore of Lake Champlain. The chemical is designed to kill an invasive organism called sea lamprey. The parasites have decimated native trout and freshwater salmon in the lake. But the lamprey battle is only one front in a growing region-wide war against invasive species. Dozens of alien organisms have arrived in the North Country, some carried in the ballast tanks of freighters on the St. Lawrence Seaway, others introduced as garden plants or bait fish. As Brian Mann reports, researchers say these invasive organisms could have a cumulative impact on lakes, rivers and forests that is far more rapid and perhaps more profound than global climate change.