Summary

This project established a collaborative, cross-jurisdictional approach to address the most significant technical and regulatory challenges facing northern Australia’s fledgling Tropical Rock Oyster (TRO) industry.

The project was delivered by research teams in Western Australia (A.2.1819053WA) and the Northern Territory and comprised three sub-projects, each targeting specific research needs:

Sub-Project 1 – Species Identification, Pathogen Screening and Translocation Risk assessment (NT)

This research standardised oyster common names and assessed the need for designated farming and translocation zones across northern Australia. It considered risks associated with genetic pollution of wild populations, existing knowledge of tropical ecosystems and oyster diseases, insights from the pearl industry, and current practices in edible oyster aquaculture in other regions of Australia. The findings provided a strong scientific base for biosecurity planning, management and operational procedures for the developing industry, while also and identifying key issues for further research and development.

Sub-Project 2 – Securing commercial spat (juvenile) supply

Early hatchery development work in the Northern Territory and Western Australia revealed that Tropical Rock Oysters have different larval requirements compared to the commercially produced Sydney Rock Oyster (SRO) and Pacific Oyster (PO). As a result, existing hatchery manuals for SRO and PO were found to be ineffective for TRO spat production.

Researchers utilised the Darwin Aquaculture Centre’s hatchery infrastructure and expertise to refine culture techniques for the Blacklip Rock Oyster. Hatchery trials focused on improving larval settlement procedures, including experiments on salinity levels, settlement timing, and the effectiveness of chemical and substrate cues. Additional work included conditioning broodstock and evaluating optimal hatchery systems.

Sub-Project 3 – Optimisation of grow-out methods and gear technology

This sub-project investigated optimal grow-out methods and gear technologies for Blacklip Rock Oyster production. Farming trials were conducted using intertidal systems at two sites: South Goulburn Island (supported by the Yagbani Aboriginal Corporation) and Groote Eylandt (supported by the Anindilyakwa Land Council). The trials included:

• Trial 1 Assessed the impact of three basket heights in the tidal range (standard, low and dynamic) and two stocking densities (standard and half of standard) on oyster growth, survival and basket biofouling. Data collected included growth rates, shell shape, survival and biofouling.
• Trial 2 Compared the performance of different gear types in producing marketable Blacklip Rock Oysters. This trial provided data on oyster growth and shape, as well as qualitative insights into the operation, maintenance, and performance of each system.

Expected outcomes

• A new aquaculture sector in northern Australia, employing at least 500 people, resulted a direct increase in output of $217.714 million.
• The total projected impacts on the Tropical Rock Oyster (TRO) industry’s output is estimated at $351 million.
• Biosecurity and translocation risks are clearly defined and managed through targeted policies and regulations helping to mitigate potential negative impacts of large-scale oyster farming on wild stocks – both genetically and in terms of health.
• Government, industry and consumers are now able to recognise and differentiate between the various oyster species produced across northern Australia. This helps prevent potential market confusion and supports accurate licencing and effective management of the emerging industry.
• Hatcheries have demonstrated the ability to:

1. Reliably produce commercial quantities of Blacklip Rock Oyster (S. echinata) spat.
2. Condition and spawn broodstock year-round.
3. Increase oyster production due to the improved spat availability.
4. Improved oyster growth and survival rates.

• These advancements have increased confidence among industry investors and proponents, including Aboriginal communities, in the development and sustainable growth of commercial aquaculture businesses.
• The project has increased capacity within Aboriginal partner organisations, enabling great participation in the industry.