Shellfish reefs are culturally, economically, and ecologically important but have almost entirely disappeared from Australia’s coastlines. In the Noosa River estuary, oysters were once abundant but have not recovered since over-harvesting in the late 19th century. The Noosa estuary appears to be a melting pot for both warm and cool climate species, and although a variety of oysters have been recorded, DNA evidence is required for confident identification. Due to differences in the biology and habitat preferences of oyster species some are likely to be more suitable for shellfish reef restoration projects than others, but this knowledge of which oyster to use and when is limited for places like Noosa.

In this project, Griffith University used traditional collection methods as well as CSI-like environmental DNA technology to test the diversity of species present, building on the existing knowledgebase developed through NBRF and its research partners in existing projects. Although the new methods used enables detection of oyster species that are rare or that live in areas that are difficult to access; no evidence was found of the occurrence of the elusive “Noosa Mud Oyster” or if it was a separate species from the rock oysters.

This project also evaluated which surfaces are best for a range of oyster species to settle on. To do this, a few different types of settlement plates and dead oyster shell were deployed over the 2019 Summer to catch baby oysters. Despite the dry conditions, quite a few oysters were caught around the estuary and genetic analyses was able to determine their identity. This critical genetic information will be used to provide a key for future monitoring and for the assessment of oyster diversity throughout the Noosa estuary.