Cultivation of Gracilaria gracilis in an Aquaculture System at Mondego River (Portugal) Estuary Adjacent Terrain

Seaweeds are one of the most sustainable and feasible natural sources to the imminent food shortage, due to their nutritional profile. Seaweed aquaculture is an important tool for seaweed food safety and maintain the nutritional value. The specie Gracilaria gracilis (Rhodophyta) is an edible seaweed, which can contribute to a balanced diet. The objective of this work was to evaluate the nutritional profile of G. gracilis in semi-controlled aquaculture (SCA), located in the estuarine zone of the Mondego River (Figueira da Foz, Portugal) compared to specimens harvested in the natural environment (SW). G. gracilis that presented good growth rate in the aquaculture system (4.70%/day), and its biomass, analyzed by Weende method, showed that SCA had different nutritional profile than SW. A fresh weight of cultivated G. gracilis showed some differences in moisture (SCA = 85.49% ± 0.02; SW = 86.04% ± 0.01), ash (SCA = 3.96% ± 0.01; SW = 4,10% ± 0.01), fat (SCA = 0.01% ± 0.00; SW = 0.01% ± 0.00), fiber (SCA = 0.79% ± 0.01; SW = 0,68% ± 0.00), protein (SCA = 2.07% ± 0.01; SW = 2.54% ± 0.01) and carbohydrate (SCA = 7.69% ± 0.02; SW = 6.64% ± 0.01). These results support the importance of G. gracilis aquaculture cultivation, maintaining the seaweed nutritional quality, when compared to the wild specimens obtained from the sea. Thus, promoting an eco-sustainable way of cultivating seaweeds for nutritious food purposes and even promoting the global food safety.