Populations of native lamprey are generally in decline throughout their range. May have some value as forage for predatory game fish. Nests are built in shallow gravelly riffles. The adults constantly work on the nests with short interruptions for spawning. The female attaches to a rock and the male attaches to her head, wrapping his tail around hers to bring the genital openings close together.
Adults die soon after spawning, the eggs hatching about two weeks later.
After hatching, the ammocoetes drift downstream to quiet waters where they live in small burrows in the bottom ooze for 7-9 years. At this stage they are not parasitic, feeding largely on algae and microscopic animals. Ammocetes metamorphose in the fall, remain in the streams over winter, then move downstream to rivers and lakes in search of hosts. After two years as parasites, the adults return upstream to spawn and die. The native lamprey have evolved with, and live in balance with, their host populations.