The key results of this project are:
- The environmental footprint of all the studied seacage farms was highly localised. Benthic data from under the farms and with distance indicated moderate enrichment under the cages with no clearly discernible impact of fish cage aquaculture on the adjacent environment. At Ayong Farm, rates of benthic DIC (dissolved inorganic carbon), dissolved nutrient, sulfide, and methane release, and rates of sulfate reduction, were higher under the fish cages than at 100m distance down-current. At the Awarange Bay farm, most differences were inconsistent with season. Although the rates of pelagic and benthic respiration were greater at the Ayong Farm, proportionally more organic carbon was exported (29%) to the adjacent environment or buried (4%) than at the Sulawesi operation (16% and 2%, respectively). More carbon was mineralised in the water column than in the sediment at the Ayong Farm, whereas the opposite is true for the Sulawesi farm, but helping to minimise export to adjacent habitats.
- Understanding the circulation of water in the vicinity of farms is critical to understanding the physical dispersal of aquaculture wastes. In microtidal environments such as those we studied in Indonesia, wastes do not disperse far from the cage area. In these environments chemical and biological transformation processes are more important in removing waste products. The bulk of the farm-derived organic matter is primarily broken down by microbes in the water-column and secondarily on the seabed. In macrotidal environments such as Bathurst Island, strong tidal currents remove and distribute waste products over a large area.
A decision support tool for calculating the environmental carrying capacity for seacage aquaculture has been developed, and is publicly available.
CADS_TOOL (Cage Aquaculture Decision Support Tool)
- In collaboration with FIS 2002/076, a map series has been produced for South Sulawesi that can be used as a model for other provinces.
Seacage Aquaculture Site Suitability Map, Barru Regency, South Sulawesi.
- In collaboration with FIS 2002/076, a Local Advisory Committee for aquaculture planning has been established in South Sulawesi, and a National Steering Committee established in Jakarta to further extend the project recommendations nationally.