Aquatic resources of the St Croix River Basin

Historically, 110 species of fish representing 24 families have been identified from the St Croix River basin. Six species have been introduced, while seven other native species have not been collected since 1974. Ammocrypta asprella is on Wisconsin's endangered species list, and eight species are on its threatened list. There are 39 freshwater mussel species in the basin; Lampsilis higginsi and Quadrula fragosa are on the federal endangered species list. Nine species are considered endangered and three threatened in Wisconsin. Aquatic insect surveys on the St Croix River and a few tributaries identified invertebrates representing 332 taxa, 235 genera, and 100 families. In 1968, with the enactment of the National Wild & Scenic Rivers Act, 165 km of the St Croix River and 157 km of the Namekegon River became one of the first eight rivers to become part of the National Wild and Scenic Riverway system. In 1972, 87 km of the lower St Croix River were added to the system. -from Authors