Documented incidence of the brook lamprey is limited to the smaller streams in the northeast quarter of the state. In all modern fish collections in this state but one, this interesting species was taken during its spawning season in April. The single specimen taken in the Volga River was captured by electro-fishing in late November. The secretive nature of its habits makes knowledge of its distribution rather vague and undetermined.

The color of the American brook lamprey is 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 rather in several groups or clusters. There are from 65 to 70 myomeres between the last gill slit and the anus. A length of about 5 to 8 inches is attained at adulthood.

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 upon completion of spawning.

The food habits of the American brook lamprey are indeed very interesting. In its larval stage it feeds largely upon minute plants, animals and bits of organic matter. After the animal reaches maturity in the fall, the digestive system becomes non-functional, indicating that little or no food is consumed from fall until the next spring.

Like the other lampreys in Iowa, these fish have no importance to anglers.

*Mayhew, J. (editor). 1987. Iowa Fish and Fishing. Iowa Department of Natural Resources, Des Moines, Iowa. 323 pp.