American Brook Lamprey

American Brook Lamprey, Lampetra appendix
Illustration by D. A. Neely

The American brook lamprey is a non-parasitic aquatic species.  Taxonomically, it is not considered a true fish because it is so different from other fish species.  (True fish have jaws.  Lampreys are jawless).  Unlike the sea lamprey, a non-native species which latches on to and sucks the blood from other fish with its toothy circular mouth, the adult American brook lamprey doesn’t eat.  At all.  Adults spawn (make a nest in gravel, then lay and fertilize eggs) in late March or early April.  They die soon after.  The eggs hatch into larvae, called ammoecetes.  The lamprey may exist as an ammoecete for up to  seven years, feeding on algae, before undergoing metamorphosis into its adult form during late summer.  Spawning occurs soon after metamorphosis.

The range of the American brook lamprey includes the northeast quarter of the United States, from Minnesota to Arkansas to Virginia and north to the St. Lawrence River.  Although secure in most of its range, in the mid-Atlantic region, American brook lamprey populations are declining.  In Maryland, it is considered Threatened. 

The American brook lamprey is found within slow-moving warm-water streams with forested edges on the Western Shore of the Coastal Plain (south of I-95) in Maryland.  This area of the state is under the increasing pressure of urbanization.  Loss or degradation of habitat due to development and a lack of mitigation are chief contributors to species decline.  Local governments, which determine many zoning laws, can have a huge impact on the state of riparian habitats, and thus have a significant opportunity for conservation.  Cooperative participation between MD DNR and local planning agencies is vital if we are to make an effort to conserve the American brook lamprey, and all species of flora and fauna along these waterways.

For more information on this and other fish and herpetological species, checkout the Maryland Biological Stream Survey. You’ll find keys to taxonomy, range maps, volunteer opportunities and other useful information.