Zebra mussels and other non-native organisms can have severe negative ecological and economic effects.
Minnesota and Wisconsin meeting will cover the threat to the St. Croix River and possible steps to protect it.
One of the biggest invaders in the St. Croix River is the zebra mussel.
National Park Service scientists say the invasive species’ numbers were down again in 2013.
For two consecutive years, almost none of the invasive species have been found in the river.
A new survey of the river has given boaters, native mussels and swimmers reason for hope.