Downstream migration of early larvae of the European river lamprey Lampetra fluviatilis

Invasion of the European River Lamprey Lampetra fluviatilis in the Upper Volga

The European river lamprey came to the Upper Volga from the Baltic Sea most probably via a system of shipways developed in the 18th and 19th centuries. The Vyshnii Volochek, Tikhvin, and Mariinskaya water systems are possible invasion pathways for this species. Dispersal and colonization of the Caspian Basin was likely a combination of upstream and downstream migrations. Analysis of museum and our own samples showed that lamprey possibly migrated upstream (for spawning) along rivers of the Baltic Basin until they reached the watershed boundary from which they could disperse downstream (in the juvenile period) into rivers of the Caspian Basin. Dispersal in the Volga River could occur in accordance with the migration cycle of this opportunistic lamprey species and lead to the present distribution. Key features (dentition and number of trunk myomeres) showed that lamprey from the studied area are similar to lampreys from the Baltic basin, although specimens in each population have their own peculiarities in morphology (size and coloration). Genetic data (Cyt-b) support the idea of a relatively recent invasion of lamprey into the Upper Volga. The haplotype, found in three rivers, is one of the most widespread in Europe and is found along the supposed route of invasion.