Economic feasibility of small-scale aquaculture of scallop (Nodipecten nodosus) and cobia (Rachycentron canadum) in a multi-trophic system on the southeastern Atlantic coast

ABSTRACT This study evaluated the economic feasibility of scallop monoculture (Nodipecten nodosus) in six 100-meter longlines, monoculture of cobia (Rachycentron canadum) in twelve 565.5 m3 net cages, and the integrated multitrophic aquaculture system (IMTA) with both species, in four longlines and six net cages of the same dimensions, in an area of 5,000 m2, on the southeastern coast of Brazil. This study aimed to determine whether this approach could provide greater profitability and resilience than traditional monocultures. Investments, operating costs, and profitability were estimated for the three production systems according to the variation in survival, productivity, and market prices. The financial indicators showed positive values for the three systems evaluated. There was a reduction of US$ 1.88 per dozen scallops from scallop monoculture to IMTA and US$ 0.22 per kg of cobia from cobia monoculture to IMTA. However, comparatively, scallop monoculture had the worst results. For this system, although the IRR (35.03%) and MIRR (19.37%) are above the MRA (12%), the NPV, ANPV, and PP (US$ 69,785.07, US$ 12,350.85 and 3.71 years, respectively), had lower economic attractiveness when compared to the other two systems evaluated. Between cobia monoculture and IMTA, there is a certain proximity of results. The IMTA system showed a slight advantage in terms of the highest market prices. The diversification of production is an interesting option even with the greater associated investment, which can favor economic returns and mitigate the risks of small-scale systems dedicated to monocultures.