Potamodromy, migration for reproduction within freshwater systems, is widely practiced among fishes, but has rarely been reported for Micropterus spp. Recent evidence has shown that shoal bass (M. cataractae; Williams & Burgess, 1999) in the upper Flint River, USA, undergo migrations during the spawning season to large shoal complexes; however, the magnitude and prevalence of these migrations are unknown. To test the hypothesis that these fish exhibit potadromy, 376 shoal bass were tagged with anchor tags over a four-year period. Each spring, shoal bass migrated up to 200 km to reach spawning areas in the piedmont, and these migrations appeared to be more common in fish living in the coastal plain area of the river. Fish from the piedmont area moved less, likely due to proximity of spawning habitat. Results of this study have suggested that shoal bass are highly migratory in connected systems, traveling long distances to spawn in specific areas. Thus, the scope of shoal bass management and conservation has broadened considerably. Other Micropterus species dwelling in lotic habitats may exhibit similar migratory patterns in their native and/or introduced ranges, and this possibility could be examined using mark-recapture techniques similar to those used in this study.
