The adults spawn in May and June, and the eggs are deposited into depressions in the riverbed. As in river lampreys, a number of males mate with one female (5). The larvae (known as ammocoetes) live for three to seven years in the sand or mud, and filter organic matter from the water for nourishment (5). As they mature they develop eyes and the sucker-like mouth, and as sexual maturity is approached they stop feeding entirely. A few weeks after spawning the adults die (5). Unlike river and sea lampreys this species does not migrate out to sea, but spends the whole life-cycle in fresh water (it is not anadromous) (4).