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 watermilfoil, 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: