Movement patterns of imperiled blue shiners (Pisces: Cyprinidae) among habitat patches

Abstract – The blue shiner ( Cyprinella caerulea ) is a federally threatened cyprinid that inhabits discrete habitat patches, but whether the fish in these patches represent distinct subpopulations or a continuous population is not known. Movement patterns of adult blue shiners among habitat patches in the Conasauga River (Tennessee and Georgia, USA) were investigated to determine if movement among patches was unrestricted, or if each patch represented a relatively discrete subpopulation. Movement was restricted to a small proportion of individuals at any given time, and most fish that moved did so between adjacent habitat patches. The average distance moved by blue shiners over the two study periods (1997 and 1998) was just 130.7 m. Riffle and glide mesohabitats were not barriers to the dispersal of blue shiners, and fish moved both upstream and downstream in approximately equal numbers. It is suggested that the fish that are mobile at a given time are responsible for recolonization of habitat patches via cumulative, stepwise movements between adjacent patches, and that intervening patches must be present to maintain connectivity of the entire population. Blue shiners exist as relatively discrete subpopulations in the Conasauga River. This finding emphasizes the importance of protecting habitat integrity throughout the entire course of the river to prevent isolation of subpopulations. This species may be used as a model for the conservation of other patch-restricted aquatic species. ^Note