Biofloc technology is often presented as a sustainability solution for shrimp farming becaus e it has potential to improve operational efficiency, producing higher biomass per unit of land, reducing water exchange, and limiting the use of external inputs per kilogram of shrimp produced. Yet whether these efficiency gains translate into genuine environmental sustainability remains unclear, as holistic evaluations and direct comparisons with conventional semi-extensive pond systems are still lacking. To address this gap, we apply emergy (with “m”) synthesis, a biophysical accounting framework that expresses all inputs, whether natural, purchased, or ecological, in a common baseline of solar emjoules (seJ) . We use it to assess and compare the environmental performance of shrimp farms in Tamil Nadu, India, operating with either earthen pond-based (conventional) or biofloc-based systems.
Farm-level data from representative farms of each system type were compiled into detailed emergy inventories . These were expressed per hectare per year of shrimp production and captured the quantity and quality of inputs such as feed, energy, water, carbon sources, labour, and infrastructure. Operational resource efficiency indices were calculated for water, land, feed, and electricity use . Emergy indicators , including transformity, renewability , emergy yield ratio, emergy investment ratio, emergy loading ratio (ELR), and emergy sustainability index , were then derived.
Operational resource data (Table 1) indicate that biofloc systems reduce water (1.9 vs 12.6 m³/kg) and land (0.33 vs 3.84 m²/kg) use, with similar feed demand and slightly greater electricity consumption. Preliminary emergy results suggest that while biofloc achieves higher operational efficiency, these gains do not consistently translate into emergy demand. Biofloc systems show higher dependence on non-renewable resources (higher ELR), whereas conventional ponds, though less efficient, rely more on local renewable inputs.
By integrating emergy with operational efficiency, this study highlights trade-offs hidden by narrow efficiency framings and provides a holistic basis for evaluating shrimp farming strategies and guiding sustainability policy.