Current Status of the Bluestripe Shiner, Cyprinella callitaenia, in Alabama tributaries of the Chattahoochee River

Abstract

The imperilment of many freshwater fish species has become increasingly evident across the Southeastern United States in the last half-century. Increases in water usage, urbanization, and habitat alteration, as well as decreases in flow and habitat connectivity have all contributed to the imperilment and extirpation of many populations of Southeastern fishes. The impacts of these man-made changes are especially hard on lotic species with specific life history needs and historically high population connectivity such as the Bluestripe Shiner, Cyprinella callitaenia. Populations of this species have been steadily declining across its range within the Chattahoochee, Flint, and Apalachicola rivers since the species was described in 1957. There is evidence that this decline has been greater in Alabama tributaries of the Chattahoochee river, than in other areas of its native range in Georgia and Florida. To better understand this decline and determine potential catalysts, we collected both eDNA samples and physical specimens from across the specie’s range in Alabama, Georgia, and Florida. From these, we determined the current distribution of the species within Alabama and the genetic integrity of several populations within the ACF drainage. We believe that the Bluestripe Shiner has been extirpated from most of its native range within Alabama. Furthermore, the species does not seem to be currently hybridizing with its sister species, the Blacktail Shiner, but is merely unable to adapt to increasing habitat degradation, increasing population isolation, and decreasing water availability. Alternatively, past hybridization could have occurred long enough ago or so rapidly that Bluestripe Shiner DNA has been eliminated from Blacktail Shiner populations over time, leaving no trace of the event. This analysis offers greater insight into the effects humans have had on specialized aquatic species within the ACF, and will hopefully aid in the management and protection of sensitive aquatic communities throughout the Southeastern United States.