Identification of environmental factors, with particular reference to acid sulfate soil runoff, causing production losses in Sydney rock oysters
The study has confirmed that estuarine acidification, associated with drainage of acid sulfate soils, reduces growth rates and survival in Sydney rock oysters leading to significant production losses. The work has also demonstrated that acidification is not a factor in outbreaks of QX disease. The findings have raised greater awareness of the environmental and economic impacts of estuarine acidification, and have influenced environmental decision making at local and state government levels. The oyster industry is now recognised as an important stakeholder in the management of acid sulfate soils and their impacts. Reactive and proactive strategies to manage acidification now consider the impacts on the oyster industry whereas prior to the study the industry concerns and needs were largely ignored. The industry is now represented on key management and advisory committees responsible for management of acid sulfate soils. The research has enabled oyster farmers to minimise stock losses through improved risk and stock management in parts of the estuary impacted by acidification. The study has provided a basis for more accurate diagnosis of acid-related oyster mortalities and important baseline information for environmental impact assessment in coastal development.
Keywords: acid sulfate soils, estuarine acidification, Sydney rock oyster, oyster mortalities, aluminium, iron, low pH.
1. To identify associations between water quality conditions (with particular reference to acidified water and toxic metals), other environmental factors and reduced growth rates and disease outbreaks/mortalisties in oysters at selected sites on the Hastings and Tweed Rivers.
2. To identify specific environment and management related risk factors for reduced growth rates at selected sites.
3. To identify environmental and management risk factors for specific diseases with particular reference to QX on the Tweed River.
4. To effectively communicate the findings of this study to the oyster industry and relevant agencies