An environmental DNA approach to informing restoration of the functionally extinct oyster, Ostrea angasi

Abstract

Abstract The success of oyster reef restoration can be enhanced by data on the distribution of remnant populations to inform the selection of suitable restoration locations. A quantitative polymerase chain reaction‐based environmental DNA (eDNA) assay was designed to provide distribution data for the oyster, Ostrea angasi, whose reefs are functionally extinct in Port Phillip Bay, Australia. Ostrea angasi eDNA accumulation and decay was measured in aquaria containing oysters in low and high densities, prior to testing the efficacy of the eDNA approach for detection of oysters at 15 field sites. Ostrea angasi eDNA accumulated significantly faster in aquaria where more individuals were present, while eDNA became undetectable 2–6 days after oysters were removed in low‐density treatments. The eDNA samples were successful at detecting O. angasi in the field when taken in close proximity of an oyster population. Increasing the sample number and volume could maximize oyster detection, demonstrating the potential of eDNA to identify suitable sites for the restoration of functionally extinct marine ecosystems.