Development of a Standardized Molecular Tool and Estimation of Genetic Measures for Responsible Aquaculture‐Based Fisheries Enhancement of American Shad in North and South Carolina

Abstract

AbstractAs pressure from anthropomorphic stressors continues to negatively affect the abundance of wild fish populations, aquaculture‐based fisheries enhancement (i.e., sea ranching, stock enhancement, restocking) is being used increasingly as a management option to augment and restore wild stocks. However, as supplementation with cultured individuals may have unintended impacts on the genetic fitness of a target species, emphasis is placed on scientifically based protocols for fisheries enhancement, which involves continuous observation of genetic measures within and among populations. American Shad Alosa sapidissima, which had once‐abundant spawning runs that experienced major declines throughout the early 20th century, are currently stocked in several rivers in North Carolina and South Carolina. A set of eight microsatellite markers was compiled and standardized to allow for the long‐term monitoring of genetic measures between rivers as hatchery‐based initiatives with multistate collaborators continue. Data sets from multiple spawning runs of American Shad within North and South Carolina compared using this standardized marker suite exhibited relatively high levels of genetic diversity, low inbreeding, and large effective population sizes. Furthermore, although migration is likely occurring between rivers, significant differences exist between some spawning runs. These estimates of genetic diversity and differentiation are comparable with analogous studies of American Shad, which demonstrate that these markers will be valuable for fisheries research, and the novel estimates of effective population size and bottleneck indices acquired in this study supply new information useful for management. Our results, along with future work, can be used for responsible aquaculture‐based fisheries enhancement of American Shad in North and South Carolina and can aid in the recovery efforts for this important species.