Hard to tell if this news is positive or foreboding, but the Puget Sound region starts another year with a clean bill of health on at least one front. The Washington Invasive Species Council reports that Washington is one of only five Western states remaining with no invasion of zebra mussels.

That’s good for Washington as far as it goes, but in its recently released 2012 Annual Report to the Legislature, the council writes: “If introduced, the mussels can quickly spread through rivers and lakes, impacting native species, recreation, and infrastructure for power generation, irrigation, municipalities, and industrial use… an invasion of these mussels in the Columbia River will cost the region hundreds of millions of dollars a year.” The other Western states free of zebra mussels are Oregon, Idaho, Montana, and Wyoming.

The report also spotlights invasive spartina, the emerald ash borer, the New Zealand mud snail, viral hemorrhagic septicemia (a fish disease), and a host of other non-native species ranging from yellow starthistle and cheat grass to bullfrogs. Invasive species are a major factor in worldwide declines in biodiversity and cause billions of dollars worth of damage in the United States each year. Download a copy of the 2012 report to read more.