Miami Herald: The Pacific Northwest has spent two decades retooling dams, rebuilding damaged watersheds and restoring stream flows to keep salmon from disappearing. The United States has invested billions in the effort – $350 million in 2004 alone – by far the most money spent on any endangered species. But a new threat is more devastating than the gill nets that sent dozens of salmon runs into extinction. It is more deadly than the hydroelectric turbines that still kill millions of …