Lamprey spawning migration

During recent decades, new insights regarding the spawning migration of lampreys have been gained due to advances in technology and growing interest in this key life history phase. The development of miniaturized active and passive transmitters has led to detailed information on the timing and extent of lamprey migrations. These tools, together with sophisticated laboratory experiments, have provided fertile ground for studies of lamprey migratory physiology and behavior. New molecular tools have been applied to questions of population structure and philopatry, while the identification of lamprey pheromones has illuminated heretofore unimagined mechanisms of migration and orientation. Interest in spawning migration has been spurred by the growing need to restore native lamprey populations and the equally pressing need to control invasive sea lamprey in the Laurentian Great Lakes. While important advances in anadromous lamprey biology have been achieved, gaps remain in our understanding of marine movements, species-specific differences, mechanisms of orientation, and the factors controlling passage success. Moreover, with the exception of the landlocked sea lamprey in the Great Lakes, research on the spawning migrations of the strictly potamodromous species (i.e., those that are parasitic in fresh water and the non-parasitic “brook” lampreys) is sorely lacking, seriously compromising our ability to assess what constitutes barriers to their migration.