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An Observation of Least Brook Lamprey (Lampetra aepyptera) Presence and Spawning Behavior in Five Tributary Streams of Lake Matoaka

Zack Hayden (Biology)

For several years, the presence of Least Brook lamprey eels (Lampetra aepyptera), a sensitive species of non-parasitic freshwater lamprey, has been casually observed in tributary streams surrounding Lake Matoaka in Williamsburg, VA. This study sought to document the presence and distribution of these populations, as well as document the features of their spawning season, by observing five tributary streams from mid-February to early April of 2005. Lamprey populations were found in Strawberry Plains, South Berkeley, and Pogonia streams. No lampreys were found in North Berkeley or Monticello streams, in apparent relation to the presence of heavy siltation that would likely suffocate larval lampreys. The observed spawning period began in early March and lasted for roughly four weeks-much longer than expected. Throughout the study, observations of characteristic upstream migration, downstream retreat, and breeding swarms were observed in all populations. The death of the lampreys was also documented following the end of the spawning season. Adult lampreys have been sighted in streams every year for the past several years, which, when combined with the three to seven year larval stage characteristic of the species, suggests the existence of separate breeding populations. Future research will be necessary to gain insight into possible variation among these populations. With siltation being a major threat to l. aepyptera, their documented presence should now be a consideration in decisions regarding local development.

For additional documentation, Zack Hayden provided a Word Document entitled "An Observation of Least Brook Lamprey (Lampetra aepyptera) Presence and Spawning Behavior in Five Tributary Streams of Lake Matoaka," and an Excel spreadsheet,  "Summary of the Survey."