An evaluation of oyster stocks, grow-out conditions, and off-bottom culture methods for increasing commercial production of eastern oysters (Crassostrea virginica) in the northern Gulf of Mexico

This project examined the ecologically and economically valuable eastern oyster (Crassotrea virginica) in Louisiana with two field experiments. Little information has been gathered on the performance of local Louisiana oyster stocks and no study has focused on a comparison of stocks among variable estuarine conditions. Additionally, the use of alternative grow-out methods and intensive cage aquaculture has never been evaluated in Louisiana. For the first study, a dermo-resistant stock of oysters (LSU-OYS: ‘OBOY’) was compared to three wild oyster stocks along a salinity gradient. The objectives of this study were to determine the optimal oyster stock(s) and the ideal grow-out condition(s) for intensive oyster aquaculture production. The second experiment compared the efficiencies of three commercially used, off-bottom culture systems. The objective of this study was to suggest which off-bottom grow-out method(s) is most suitable for use in Louisiana estuaries. The results of the stock comparison suggested that the selected dermo-resistant stock had greater mortality than two of the three wild stocks in all the environmental conditions tested. Specifically, wild stocks taken from low salinity areas had greater performance in test areas with low salinities while wild stocks collected from high salinity areas had greater performance at high salinity sites. The results of the grow-out method comparison revealed that an adjustable long line system (ALS) was the most suitable culture system in both high and low salinity conditions, specifically due to overall higher survival, improved growth in shell height, and reduced effort in labor and handling time. For the first time, the performance of four oyster stocks and three intensive oyster culture methods were quantified, suggesting superior stocks, grow-out conditions, and culture systems for augmenting wild production and increasing total production in the Louisiana oyster industry