Aquatic invasive species (AIS) are the species that invade our lakes, rivers, and wetlands. Many non-native species are not problematic; however, a select few are extremely competitive and pose a significant threat to our native ecosystems.
AIS that are problematic in the St. Croix watershed include: zebra mussels, Eurasian water milfoil, banded mystery snails, and curly leaf pondweed, among many others. Invasive bighead, silver, grass, and black carp are an emerging threat and potential future invaders.
Learn more about how we are dealing with invasive species: