Genetic Characterization of American Shad in the Edisto River, South Carolina, and Initial Evaluation of an Experimental Stocking Program

Abstract

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.

Developmental changes in digestive enzyme activity in American shad, Alosa sapidissima, during early ontogeny

“…The species is economically and ecologically important in North America, and owing to consumer demand and high economic value, the artificial culture of American shad quickly became established following its introduction into China in the early twenty-first century. As a result, a great number of studies have been conducted to elucidate the species' biology, such as feeding characteristics (Gao et al 2015a), early development (Hong et al 2013;Gao et al 2015b), age determination (Upton et al 2012), gene expression (Bi and Chen 2011;Cushman et al 2012), and allometric growth pattern (Gao et al 2015c). However, it is also necessary to evaluate new nutritional programs, in order to improve nutritional value of food and early larval growth and survival rates.…”

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

“…Instead, seven sets of data from preceding work were used (Table ): three published data sets previously described in Cushman et al. (, Edisto River) and Moyer and Williams (, Santee–Cooper River basin and Pee Dee River) and four unpublished data sets generated by the U.S. Fish and Wildlife Service (USFWS) Warm Springs Conservation Genetics Lab (CGL) in Warm Springs, Georgia (Roanoke River; G. R. Moyer and A. S. Williams, unpublished) and by the North Carolina Museum of Natural Sciences (NCMNS) in Raleigh (Cape Fear, Tar, and Roanoke rivers; H. K. Evans and M. E. Raley, unpublished).…”

“…A comprehensive description of fin clip sampling methodology for the data sets used in this study can be found in Cushman et al. () for the Edisto River, in Moyer and Williams () for the Santee–Cooper River basin and the Pee Dee River, and in Wynne et al. (, , , ) and Ricks et al.…”

“…Levels of genetic diversity and inbreeding have been characterized for spawning runs of American Shad in several rivers throughout North Carolina and South Carolina (Cushman et al. ; Moyer and Williams ; Hasselman et al. ), and genetic structure between spawning runs of American Shad along the eastern coast of North America has been well documented, revealing that some (though not all) rivers support genetically distinct stocks (Bentzen et al.…”

Lipid content and fatty acid composition in female American shad,Alosa sapidissima, at different stages of ovarian development under reared conditions

“…In the early 21st century, owing to the virtual extinction of the Chinese shad, Tenualosa reevesii , the American shad was introduced into China as an alternative species. To date, many studies report the species' biology and spawning behaviour (Bilkovic, Olney, & Hershner, ; Cushman, Tarpey, Post, Ware, & Darden, ; Gao et al, ; Hong, Zhu, Chen, Pan, & Li, ; Liu et al, ; Maltais, Daigle, Colbeck, & Dodson, ). However, the importance of lipid storage, mobilization, and the changes of fatty acids in different tissues to American shad reproduction has not been reported.…”