The Santee–Cooper system in South Carolina, USA, is a complex of reservoirs, rivers, and canals. The endangered shortnose sturgeon Acipenser brevirostrum inhabits the rivers below the reservoirs and has also occasionally been reported anecdotally in the reservoirs themselves. During 1998–1999, we conducted a study to determine whether shortnose sturgeon were reproducing in the reservoirs, and if so, to evaluate habitat use and degree of separation from the riverine groups. Fourteen shortnose sturgeon were captured from the reservoirs, and all (even gravid females) appeared qualitatively less robust than riverine fish previously captured below one of the dams. Ten of the fish were implanted with transmitters and tracked at least once per week. Fish tracked in the upper reservoir, Lake Marion, stayed in the upper portion of that lake or in tributary streams flowing into it. We documented seasonal movements among four primary areas of upper Lake Marion and its tributaries. A spawning site on one of the tributaries, the Congaree River, was verified by collection of viable eggs. Genetic analysis demonstrated significant differences between samples from the Santee–Cooper reservoirs and three nearby coastal rivers. Cooper River samples, however, were not significantly different from reservoir samples, although appreciable differences in haplotype frequencies were observed. The need for a larger sample size was apparent. Although telemetry, spawning, genetic, and observational evidence suggests that the shortnose sturgeon in the reservoirs form a separate population segment, the results are not conclusive because possible downstream movement, especially of juveniles, through the dams has not been investigated.

The American shad Alosa sapidissima is an anadromous clupeid with once‐prolific stocks that have experienced major coastwide declines in abundance over the past century. The American shad spawning run in the Edisto River (South Carolina) has been exhibiting the same decreases as spawning runs in other coastal rivers, and stocking is now being considered as a restoration option for this river system. We utilized a suite of 13 microsatellite loci to provide a baseline genetic characterization of the Edisto River spawning run prior to supplementation and to evaluate the initial success of an experimental stocking program enacted from 2008 to 2010. No significant temporal genetic differentiation was found between sampling years, indicating that the genetic composition of the Edisto River spawning run is temporally stable over short time frames. Estimates of genetic diversity for Edisto River American shad were high (observed heterozygosity = 0.82–0.85) and similar to those observed in other river systems. Estimates of effective population size (3,505–8,379) resembled those reported for other diadromous species and were within the levels recommended for maintaining evolutionary potential. Hatchery‐produced individuals were detected within the 2010 year‐class of juvenile American shad prior to out‐migration (11/314 fish, or 3.5%), demonstrating initial success of the stocking effort (i.e., contribution of hatchery fish to the wild stock). Our results provide valuable information that can be incorporated into management plans for aiding the recovery of American shad in the Edisto River.