Distribution, abundance, and habitat requirements of the threatened Least Brook Lamprey, Lampetra aepyptera, in the Shawnee National Forest

The Least Brook Lamprey has been considered a "Threatened" species in Illinois since 1989 due to its limited distribution and presumed rarity. I investigated the distribution, abundance, and reproduction of this species in southern Illinois from June 2005 through June 2006. Its distribution is currently confined to four stream systems located in the Shawnee National Forest.;Least Brook Lamprey spawning occurred from the second week in March to the second week in April. Approximately 1,200 Least Brook Lampreys were recorded from 118 spawning sites throughout the four stream systems. The habitat requirements of larval (i.e., clear, sand bottomed pools) and spawning adult lampreys (i.e., heads of rocky riffles) are life-stage specific. Due to this fact, the alteration or destruction of either pool or riffle habitat could ultimately result in extinction of localized populations. Considering this, it is imperative that protective measures be implemented to assure preservation of essential habitat.