CARBON & eNVIRONMENTAL ACCOUNTING
Now, more than ever, there is a collective desire amongst the community and regulators to see industries move toward more sustainable and integrated production systems and an overall reduction in industry carbon footprints where possible. This drive is underpinned by the Australian Government’s Paris agreement obligations to reduce net emissions as well as a community expectation that industries are committed to reducing their environmental impact footprint and this is seen most through consumer choice metrics.
In order to influence the movement to more sustainable, carbon neutral operations, there are several regulated and non-regulated (voluntary) market mechanisms and accreditation pathways available for industry which in some instances canprovide additional revenue as a payment for carbon capture and storage (Australian Carbon Credit Units) and payment for ecosystem services as well as appealing to the conscious consumer through accreditation through carbon neutral or other sustainable seafood or environmental frameworks.
Navigating the regulatory and political landscape for carbon and climate change policy is challenging. As a result, in 2021, Oysters Australia engaged Nine-Squared to provide some targeted understanding of what opportunities exist in the carbon neutral and environmental accounting space and how they specifically apply to the industry, the benefits, and path to implementation.
The outputs from this project are provided below in the form of:
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4-page summary handout discussing carbon neutral certification for oyster farmers
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1 hour webinar recording summarising the project and findings (see below)
RESTORATIVE AQUACULTURE: EVIDENCE OF ENVIRONMENTAL BENEFIT
Oyster farming is increasingly recognised for the environmental benefits it provides, including water filtration, nutrient removal and habitat creation. To test those benefits against a credible international standard, FRDC Project 2024-057 assessed NSW oyster aquaculture against The Nature Conservancy's (TNC) Principles of Restorative Aquaculture and its Monitoring, Evaluation and Learning (MEL) Framework.
The assessment was based on the NSW industry. However, much of it is relevant to oyster farming across Australia. The mechanisms behind these benefits are common to filter-feeding oysters wherever they are farmed. Many of the supporting studies came from interstate and international systems. Nutrient removal rates were calculated for both Sydney rock oysters and Pacific oysters. The findings on carbon apply to the whole industry.
NSW oyster farming was rated Most Likely Restorative for both water quality and habitat & biodiversity.
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Water quality: Every 1,000 tonnes of Sydney rock oysters harvested removes 5.58 tonnes of nitrogen and 0.69 tonnes of phosphorus. Every 1,000 tonnes of Pacific oysters removes 4.46 tonnes of nitrogen and 0.55 tonnes of phosphorus. NSW oysters also filter roughly 2 trillion litres of water a year.W
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Habitat: Oyster leases in Port Stephens support 90 fish species, at levels comparable to seagrass, mangroves and natural reef. International studies show similar gains in abundance and diversity around shellfish farms.
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Low emissions: At about 0.93 kg CO₂e per kg of product, oysters are among the lowest-emission farmed proteins available.
Oyster farming was not rated as restorative for carbon sequestration. Oyster shell stores carbon, but forming shell releases CO₂. On current science, oyster farming should not be promoted as a carbon sink (this aligns with the findings of Nine-Squared above).
The benefits depend on local conditions, including estuary size, nutrient loads, farming method and species. Growers in other states should treat the NSW figures as a guide rather than a direct measure of their own contribution. Local data would strengthen the case in each jurisdiction.
A plain-English summary, the full technical report are available on the project page.
RELATED RESEARCH
Growers interested in carbon & environmental accounting should also check-out some work undertaken in New Zealand which looked at the life-cycle assessment of oysters and mussels. The project assessed the carbon footprint of farmed shellfish over their entire life cycle from farming activities, harvesting, processing, packaging, chilled distribution to domestic retail, preparing, consumption, and disposal of used shells & packaging.
