Cochran, P.A., and T.C. Pettinelli. 1987. Northern and southern brook lampreys (Ichthyomyzon fossor and I. gagei) in Minnesota. Final report submitted to the Minnesota Department of Natural Resources. 15 pp.
The presence of two brook lampreys of the genus Ichthyomyzon in Minnesota is confirmed. The northern brook lamprey (I. Fossor) occurs in the Blackhoof Creek in the Lake Superior drainage. The southern brook lamprey (I. gagei) has been found in five streams in the St. Croix River drainage. At least three relatively distinct microhabitats are used by I. gagei during its life cycle. Adults prior to spawning are found in crevices beneath boulders in deep, fast water, whereas spawning is associated with gravel substrate at the head of riffles, and larvae burrow in fine substrate in quieter water. The reproductive biology of I. gagei in Minnesota is similar to that of conspecifics in the southern part of its range.