Severe declines in commercial and recreational fisheries of the bay scallop, Argopecten irradians, have led to increased interest in US aquaculture. Since its introduction to China in the 1980s from the US, A. irradians has become one of the most important bivalves cultured and the Chinese industry has utilized selective breeding for fast growth to increase the productivity of their farms. As part of the growing scallop aquaculture industry in China, researchers have identified molecular markers (size-related quantitative trait loci (QTL) marked by microsatellites and single nucleotide polymorphisms (SNPs) in the myostatin gene) that are predictive of superior performance. The goal of this project was to improve growth performance of bay scallops on commercial shellfish aquaculture farms in North Carolina through the use of quantitative genetics and marker-assisted selection.
Mature scallops were collected from three wild populations in fall 2019 in southeastern NC (Becky’s Creek, BC), Core Sound (Big Marsh, BM), and Bogue Sound (Emerald Isle, EI). The wild scallops were brought back to the UNCW Shellfish Research Hatchery (SRH) and each group was spawned separately. Adductor muscle tissue samples were collected, DNA was extracted and analyzed for ten microsatellite markers and four SNPs in three regions of the myostatin gene associated with growth traits in Chinese bay scallops. No significant genetic differences among the three populations of NC scallops and no significant association between the genetic markers and performance in wild scallops were observed.
Offspring produced from the wild scallops in 2019 were used for growth experiments to evaluate the association of the microsatellite and myostatin SNP genetic markers with growth performance. In fall 2020, performance-based selection was utilized with each line (BC, BM, EI) sorted into “Big” and “Little” groups based on shell height and spawned separately. Adductor muscle tissue was collected from all 2020 broodstock scallops, DNA was extracted and genotyped for the ten microsatellite markers and three regions of the myostatin gene for SNP identification. Evaluation of microsatellite and SNP genetic markers revealed significant genetic differences among the six groups; however, no consistent significant association between the genetic markers and performance was observed in broodstock scallops.