Exploring and predicting the biocapacity of various fish farming systems based on modified emergy footprint accounting in the Sistan region of Iran.

Aquaculture is a form of agriculture that is practised in the Sistan region. This practice not only enhances water usage efficiency but also generates additional income for the local farmers. The extensive dependence of the aquaculture sector on energy and chemicals poses a jeopardises environmental stability and endangers the sustainability of production in the long run. The study employs emergy footprint accounting to assess the relationship between input flows and the ecological security of sustainable aquatic production in the region, across different fish farming systems, including semi-natural, concrete, and galvanised ponds. To achieve the desired outcomes, the emergy footprint accounting method requires comprehensive data on both environmental and economic inputs. The present investigation spanned four years, from 2018 to 2021. We obtained the data for this study from multiple sources, including surveys of fish farmers, expert opinions from media reports, and meteorological data obtained from weather stations located in the Sistan region. The study findings suggest that fish farming in semi-natural ponds has an ecological surplus when compared to the other two systems, owing to its higher emergy biocapacity in relation to its emergy footprint. However, it is noteworthy that semi-natural fish farming exhibited a more pronounced adverse effect on non-renewable environmental resources and resulted in the elimination of their supporting function, in comparison to the other two farming systems. This phenomenon occurred less frequently in ponds made of concrete and galvanised material. However, the ecological impact generated by these ponds surpassed their biocapacity, leading to an ecological deficit, insecurity, and exertion on the surrounding ecosystem. The findings suggest that enhancing the efficient utilisation of inputs in both concrete and galvanised ponds can lead to improved sustainability and ecological safety of their production. The adoption of strategies such as augmenting the size of juvenile fish to curtail the duration of aquaculture production in semi-natural fish farming is expected to have a limited effect on non-renewable ecological resources.