American brook lamprey
Lampetra appendix (DeKay, 1842)

member of the Lamprey Family (Petromyzontidae)


Whitewater River, Winona County, Minnesota 24 September 1990

photos by Konrad P. Schmidt












What's In a Name?
American Brook Lamprey: a rock-licking fish that lives in small streams in North America; based on its habit of clinging to rocks with its mouth 

Lampetra (lam-pet´-trah) means to" lick a rock" in Latin
appendix (ap-pen´-dicks) means "appendage" in Latin


    Where Do They Live?
In Minnesota, American brook lampreys are found mostly in the southern part of the state. Specifically, they occur in the Cannon, Zumbro, Whitewater, Root, and Upper Iowa rivers and their tributaries.  They also occur in two small tributaries of the Minnesota River in Scott County and in Valley Creek, a small tributary to the lower St. Croix River. 

They prefer cool, often spring fed, streams ranging from small to medium size with clear water. Bottoms are usually made up of sand or small-sized gravel. They share this habitat with many kinds of fish, such as sculpins, brook trout, and brown trout.

"Cool Fact": The American brook lamprey is one of three species of non-parasitic (or non-predatory) lampreys in Minnesota.



How Big Do They Get?
How Long Do They Live?
Compared to most other fish in Minnesota, American brook Lampreys have a very unusual growth pattern. The adults as smaller than the larvae. 
This is because the larvae spend about 4-7 years eating and growing before they change into adults. The adults, which do not grow, live for 8-9 months, spawn, and die. 

American brook lampreys grow to a maximum size of about 260 mm (10 in). Male lampreys grow a bit longer than females do.

    What Do They Eat?
During the larval period, American brook lampreys burrow into soft sand and silt bottoms. There they filter-feed on a bland diet made up of very small plant and animal life, such as protozoans, diatoms, algae, desmids, and pollen. During the short adult period, the brook lamprey does not eat.

What Eats Them?
American brook lampreys easily become prey while in the larval form or as newly formed adults. They are eaten by walleyes, muskellunge, and smallmouth bass during these periods.


How Do They Reproduce?
Spawning season for the American brook lamprey usually begins in April and goes through May. The males appear at the spawning grounds before the females in order to build the nest. 

The nest is the size of a saucer and shaped similar to a hen's egg. The male creates it by using his sucker mouth to move gravel and pebbles around in the stream bed. 

When the females arrive at the spawning area, they go to the nest and attach themselves to a rock with their sucker mouths. The male then joins her and the female lays her eggs while the male fertilizes them. The fertilized eggs then fall into the nest and are covered slightly by the gravel and sand that has been disturbed by the two fish. Shortly after the two adults are done spawning, they die. 

The female can lay 1,000-5,000 eggs, depending on her size. The embryos hatch in about three weeks, and the larvae (called ammocoetes) drift downstream. Eventually, they burrow in soft sand and silt, where they feed and grow for 4-7 years. Ammocoetes transform into adults in the fall, spawn the following spring, and die.


Conservation and Management
At one time the American brook lamprey was listed as a species of special concern. It was known from only a few places and was considered rare. In the late 1980s and early 1990s, Dr. Neil Mundahl from Minnesota State University at Winona discovered it occurred at more sites and was far more abundant than we thought. At present, this species has no special conservation status in Minnesota, but Dr. Mundahl continues to monitor its populations.




Permission is granted for the non-commercial educational or scientific use of the text and images on this Web document. Please credit the author or authors listed below.

Photographs by Konrad P. Schmidt
Text by Nicole Paulson & Jay T. Hatch in cooperation with
the Minnesota Department of Natural Resources' MinnAqua Aquatic Program

This page developed with funds from the
MinnAqua Program
(Minnesota Department of Natural Resources, Division of Fisheries)
and the
Sport Fish Restoration Program (Fish and Wildlife Service, US Department of the Interior)

Maintained by Jay T. Hatch
General College and James Ford Bell Museum of Natural History
University of Minnesota, Minneapolis/St. Paul

Last updated 23 October 2002