American Brook Lamprey

Characteristics

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 just 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.

Distribution

The American Brook Lamprey's secretive nature makes its distribution unclear and undetermined. Historically thought to be limited to smaller streams in northeast 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 part of the Iowa River drainage.

Foods

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

None

Details

American Brook Lampreys live in permanent streams ranging 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. 

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 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.

Sources:

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.