Adult zebra mussels have become established in one of the few remaining pristine river systems east of the Mississippi River, threatening other native mussels populations, according to an interagency task force.
Task force monitoring has observed young zebra mussels in the lower St. Croix River on the Wisconsin-Minnesota border, indicating that adult mussels have established themselves and are reproducing there for the first time.
"We are very concerned about this issue," said Ron Benjamin, Wisconsin Department of Natural Resources fisheries team leader along the Mississippi River and a member of the St. Croix River Zebra Mussel Task Force. "The discovery is really disappointing because the St. Croix is such a unique resource and we have invested considerable effort in avoiding this situation."
"The St. Croix is was one of the eight rivers protected in the original national scenic riverway legislation in the early 1970s, and it still has all the fauna that were in it when European explorers first came to this area," Benjamin said. The St. Croix is home to many rare native mussels populations, including the endangered Higgin's eye pearly mussel and winged mapleleaf mussel.
Adult zebra mussels have established themselves in Lake Michigan, the Mississippi River, and are now working their way inland. Populations have been confirmed in 17 inland lakes.
(Source: Environment News Service)