Growth performance of Eastern oysters Crassostrea virginica in Atlantic Canada: Effect of the culture gear

Size groups of Eastern oysters Crassostrea virginica (20–30 mm, 30–40 mm, 40–50 mm, and 50–60 mm) were individually labeled, randomly assigned to two types of floating culture gears (horizontal ropes and Vexar bags) and deployed at various locations in northern New Brunswick, Canada. Results indicated that the rope-grown oysters substantially outperformed those deployed in floating bags; after one growing season, shell growth was 60% higher and weight gain was nearly double. More than 95% of the variance in shell or weight growth could be explained by the culture gear. The difference in oyster performance between the two culture gears was greater at certain sites, or a significant culture gear by site effect. In particular, it appeared that growth in the floating bags was relatively depressed at the more dynamic sites with higher wave action. Based on the rope-grown oyster performance, we would suggest that the environmental conditions at the various locations tested in this study would support similar levels of commercial oyster production. The prediction would be quite different, however, if the site productivity assessment were based on performance data from floating oyster bags.

► The Culture gear has a significant effect on the linear and weight growth of the Eastern oyster
► After one season, shell growth was 60% higher and weight gain was nearly double for the rope-grown compared to the bag-grown oysters
► Similar growth performance across sites was achieved with the rope-grown Culture gear but the significant Cuture Gear x Site illustrates the variable performance of the floating oyster bag