Growth performance of fish in any production system is affected by environment and genetics. Atlantic salmon are grown in a variety of conditions including different salinities, culture systems, temperatures, water quality, and photoperiods. In addition, rearing strategies such as stocking densities or feeding regimens can create different environments. Given the diversity across production environments, Atlantic salmon can be grown in environments that differ from those where broodstock were selected and evaluated. The Saint John River (SJR) strain has been selected for growth in net pens at the National Cold Water Marine Aquaculture Center (NCWMAC) for more than four generations. The NCWMAC also maintains the Gaspe strain of Atlantic salmon, obtained from Troutlodge in 2010. These fish were selected in tanks for growth for two generations. With increased interest in land based Atlantic salmon facilities, we want to know if our SJR strain will perform as well or better than the Gaspe strain in closed systems.
It is possible that a genetically improved strain like the NCWMAC SJR strain does not respond similarly in all environments. Studies have shown that genotype × environment (G × E) interactions occur and affect fish performance. For example, G × E interactions occur for production traits, such as body weight and fillet yield in rainbow trout and other species of fish. Most studies only include a single genetic line of fish and identify G × E effects at the family level for traits such as condition factor, body weight, and thermal growth coefficient. Research at the National Center for Cool and Cold Water Aquaculture have examined five genetic lines of rainbow trout and found a G × E effect for fillet yield in fish harvested at 500 g or less.
There is no information regarding G × E effects among different genetic lines of Atlantic salmon. Understanding G × E effects is important to producers who have interest in identifying genetic lines that are best suited for their production environment and management style. To address this research gap, SJR and Gaspe strain Atlantic salmon broodstock were spawned in 2020 and eggs from each strain were sent to the Conservation Fund’s Freshwater Institute located in West Virginia and the Northern Aquaculture Demonstration Facility in Wisconsin. Another batch of eggs were kept and maintained at the NCWMAC. The fish will be grown in a recirculating aquaculture system and evaluated at harvest. Atlantic salmon parr will be compared across the three locations to help identify G x E effects between the two strains of Atlantic salmon.