Comparing triploid and diploid growth and mortality in farmed oysters, Crassostrea virginica, in the northern Gulf of Mexico

Abstract

The significance of the triploid advantage, in terms of growth and survival, varies across studies and environmental conditions. A meta-analysis was performed with 30 studies using chemically induced triploids and triploids produced by a diploid x tetraploid cross. The positive response ratios in 110 of the 121 unique experiments suggested in a significant growth advantage of the triploid oyster over the diploid oyster in whole wet weight and shell height. To compare growth and mortality locally, paired triploid and diploid Crassostrea virginica were deployed adjacent to commercial oyster farms in Alabama. Growth metrics and infection intensity of Perkinsus marinus were significantly different across sites and ploidy and, in all cases, the result was higher in triploid oysters. Triploid oysters experienced significantly higher mortality than diploid oysters at three of four sites and the results highlight the need for a better understanding of the triggers of summer mortality in triploids.