Global aquaculture production of shrimp has increased drastically over the last two decades with production increasing from ~1.3 million MT in 2001 to ~7.5 million MT by 2021. Despite the global increase in farmed shrimp production, US shrimp aquaculture production has remained relatively low over this same period (<3,000 MT in most years with a maximum of ~6,000 MT in 2003). The lack of growth in US shrimp aquaculture can be attributed to many factors, including low costs of imported products relative to US products, permitting issues and regulations, and land use conflicts. However, there is one sector of the industry that has shown signs of growth: inland farms. It is estimated that there are ~100 inland shrimp farms in operation in the US (including startups and “backyard” farms) and these farms produce >400 MT/year. Some of these use outdoor ponds/tanks and have access to low-saline groundwater, but a majority of inland farms are indoors, utilize recirculating aquaculture systems (RAS), and rely on seawater made from natural or synthetic sea salts.
Inland farming is attractive for several reasons, including increased biosecurity, potential for year-round production, farms can be closer to major markets allowing for direct marketing to consumers and food service industry, and locating farms away from sensitive coastal areas. Inland farming does have inherent challenges though, most notably high capital and operational costs. Reducing capital costs industry-wide will be difficult, as most inland farms will require costly infrastructure, and solutions for capital reduction may be region specific. Thus, to support the continued growth of inland shrimp farming, efforts are needed to reduce production/operational costs.
This project focused on the genetics of Litopenaeus vannamei growth and survival under normal and reduced salinity conditions. The impacts of reducing salinity on the performance of selectively bred L. vannamei were determined, so that inland farmers can weigh the economic benefits of reducing salinity (i.e. reducing input costs) against the impacts on shrimp performance. In addition, genetic correlations were estimated and these estimates will allow breeders to determine trade-offs in genetic gain if selection and farming occur at different salinities and, ultimately, determine if developing separate shrimp lines for high and low/reduced salinity farming is warranted. Lastly, the use of genomic data was found to provide improvements in model fit and genetic parameter estimates (heritability and genetic correlations), as well as increases in selection accuracy for growth (≥6.5%). The benefits for survival were less clear due to a large genotype × environment effects for salinities tested across two generations.