Title:

PIRSA Initiative II: carrying capacity of Spencer Gulf: hydrodynamic and biogeochemical measurement modelling and performance monitoring

Project Number:

2009-046

Organisation:

Department of Primary Industries and Regions South Australia (PIRSA)

Principal Investigator:

John Middleton

Project Status:

Completed

FRDC Expenditure:

$1,168,929.00

Program(s):

Industry

Need

PIRSA Aquaculture have indicated that they intend to develop a number of new aquaculture zones around the state over the next 5 years as well as revisit early assumptions of carrying capacity estimates developed in Innovative Solutions 1, in order to meet the anticipated expansion of the aquaculture industry within South Australia. This expansion is necessary to meet SA’s target of $2 billion in seafood production by 2015. It is also essential that PIRSA Aquaculture is prepared for successful propagation of southern bluefin tuna, which could see the farmed biomass of this species increase significantly in a few years, particularly in Spencer Gulf where existing aquaculture infrastructure and support services are in place. The ability to obtain accurate estimates of spatial and temporal variability in the cycling of carbon and other macro-nutrients through the ecosystems in Spencer Gulf will provide important information about potential risks and impacts of increased aquaculture activities in the Gulf. This need will be met through the development of calibrated hydrodynamic and bio-geochemical models for Spencer Gulf that will also determine the carrying capacity of aquaculture areas, including the concurrent use of both supplementary and non-supplementary fed organisms within each area. Further, the development of strategies for long-term performance monitoring, management and mitigation are needed for the aquaculture areas in Spencer Gulf. These outcomes will further justify the South Australian government’s approach to sustainable aquaculture development as directed by the Aquaculture Act 2001. The stated limits in the ability to deliver the above for other areas (e.g. shelf waters off Ceduna) or species (e.g. scallops) by the researchers will aid PIRSA Aquaculture to determine the future resource requirements for getting the other areas of South Australia up to the policy and regulatory standards set by this work in Spencer Gulf.

Objectives

1. To provide PIRSA Aquaculture with estimates of sustainable, carrying capacity by region, season and species for Spencer Gulf, and to investigate the impact of non-supplementary fed species (eg oysters) on these estimates.

2. To achieve this overall objective, we will collect data from five areas so as to build, calibrate and validate hydrodynamic, biogeochemical and wave models that describe the biophysical properties of the Gulf. These models and data will then be used to determine the following:

3. Provide measures of connectivity of nutrients for the Gulf, including aquaculture (supplementary fed species) and non-aquaculture (natural and industry) derived nutrient inputs.

4. Provide management with solutions to questions of carrying capacity, sustainability and impact for existing and proposed sites of aquaculture (supplementary fed species).

5. Use the carrying capacity estimates to validate or otherwise, earlier estimates that were obtained from simplified flushing models (see Methods).

6. Develop and incorporate models for non-supplementary fed species (oysters and mussels) with parameters identified that are critical to model sensitivity.

7. Develop strategies for long-term performance monitoring, management and mitigation strategies.

8. Determine limitations in the ability to deliver the above for other areas (e.g. shelf waters off Ceduna) or species (e.g. scallops).