June 19, 2019
Many people are familiar with the harmful and invasive sea lamprey that has caused problems in the Great Lakes. But did you know that not all lampreys in our area are invasive? The American brook lamprey is one of four native lamprey species in northern Michigan. Unlike the sea lamprey, this small lamprey (adults are generally 10 inches or less, compared to 25 inches or more for the sea lamprey) is non-parasitic and lives primarily in high-quality coldwater streams. The young feed on organic detritus and algae, and the adults focus on breeding and don’t eat at all. Adults spawn in gravel riffles (like this section of Vanderlip Creek on our proposed Mitchell Creek Meadows Preserve). Spawning occurs in communal nests of about 6-8 inches in diameter. A lamprey removes rocks from the nest site by suctioning onto the rocks with its suctioning disc, and swimming vigorously to deposit them off to the side, as seen in the video. As many as 14 spawning lampreys have been found in a single nest.