American Brook Lamprey

American Brook Lamprey, illustration by Maynard Reece, from Iowa Fish and Fishing


Olive-green to brown above, fading to light below. The dorsal fin is completely divided into two distinct fins. The mouth is a sucking disc, but is scarcely wider than the body. Teeth are weak and are not formed in circular rows, but are in several groups or clusters. There are 65 to 70 myomeres between the last gill slit and the anus. Adults reach about 5 to 8 inches long.


American Brook Lamprey Distribution

The American Brook Lamprey's secretive nature makes knowledge of its distribution unclear and undetermined. Historically thought to be limited to smaller streams in the northeast quarter of Iowa, it has more recently been recorded throughout the Upper Iowa, Upper Wapsipincon and Turkey River drainages, with a few scattered populations found in the upper portion of the Iowa River drainage.


Larval stage eats tiny plants, animals and bits of organic matter. After it reaches maturity in the fall, its digestive system becomes non-functional; little food is eaten from fall until the next spring.

State Record

State Records are not documented for non-game species.

Expert Tip



American Brook Lampreys live in permanent streams ranging in size from large creeks to medium-sized rivers. It is sensitive to many types of pollution, including turbidity and avoids headwater creeks and large, silty rivers. In Missouri, the American Brook Lamprey is found in clear water with slow to moderate current. In Ohio the largest populations are found spawning in gravel riffles of upland creeks, at least 15 feet average width, with high gradient. The American Brook Lamprey is commonly found only in small, upland creeks and rivers of east Tennessee and confined to small, clear streams in southeastern Minnesota.

Spawning occurs in the spring, in small depressions in the sand, usually in swift current. The larvae live in burrows for several years and the adults live from the autumn of metamorphosis to the following spring, dying after spawning.

Like the other lampreys in Iowa, these fish have no importance to anglers. It is viewed as vulnerable according to the Iowa Wildlife Action Plan, and it is on Iowa's threatened species list  (571 IAC 77.2(2) (2004)).

Recent stream sampling information is available from Iowa DNR's biological monitoring and assessment program.


Harlan, J.R., E.B. Speaker, and J. Mayhew. 1987. Iowa fish and fishing. Iowa Conservation Commission, Des Moines, Iowa. 323pp.

Iowa Department of Natural Resources, Iowa Wildlife Action Plan

Loan-Wilsey, A. K., C. L. Pierce, K. L. Kane, P. D. Brown and R. L. McNeely. 2005. The Iowa Aquatic Gap Analysis Project Final Report. Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, Ames.

Illustration by Maynard Reece, from Iowa Fish and Fishing.

Present in these Iowa water bodies:
Lake/Stream County Location Acres/Length
Turkey River (above Clermont) Fayette This section of river includes the headwaters in Howard county and flows through Winneshiek and Fayette Counties. A popular access is at Vernon Springs Park just 2.5 miles southwest of Cresco. 89.00
Waterloo Creek Allamakee Streams runs through Dorchester along Waterloo Creek Drive and Highway 76. 10.50
Maquoketa River (trout portion) Clayton The Upper Maquoketa River from Joy Springs downstream to Backbone Lake contains trout year-round. The area 3 miles southwest of Strawberry Point off 400th is stocked with catchable fish. 8.00
Wapsi River Trout Section Mitchell Located 0.5 mile west of McIntire. 2.50
Bear Creek Fayette Located 6 miles southeast of Fayette off of Kornhill Road or CR C24. Access from 128th Street. 1.20
Turner Creek Fayette Located near St. Lucas and empties into the Turkey River. 1.09
Joy Springs Clayton South on Alpha Ave, off Highway 3 about 3 miles west of Strawberry Point in Joy Springs County Park. 0.80