Economically viable marine algae-based fish feed production in Qatar

Abstract

Expanding sustainable aquaculture is crucial for meeting the growing demand for fish and ensuring global food security. This study explored the technical feasibility and economic viability of locally grown marine or brackish microalgae as fish feed ingredients. Initially, the biomass digestibility of five indigenous strains (e.g., Coelastrella sp., Dunaliella sp., Picochlorum sp., Spirulina sp., and Tetraselmis sp.) was assessed for Nile tilapia (Oreochromis niloticus); the brackish Spirulina sp. showed the highest digestibility values. Therefore, in the second phase, a Tilapia growth study was conducted using feeds containing from 0 to 25 % Spirulina sp. biomass to compare different parameters, such as weight gain (%), feed conversion ratio (FCR), and fish survival rate (%). A 5 % inclusion of Spirulina sp. biomass in the feed resulted in better Tilapia growth parameters compared to the controlled basal diet; however, higher inclusion levels of Spirulina in the feed negatively affected one or more growth parameters. However, based on the weight gain and FCR values, a 20 % inclusion of Spirulina biomass was considered for the Technoeconomic Analysis (TEA). Considering five potential cultivation scenarios, the cost of Spirulina production was determined to be $1.08–$1.36/kg dry biomass. Integrating agricultural runoff and waste fertilizers into Spirulina sp. cultivation helped reduce the cost of biomass production. If 20 % locally-grown Spirulina sp. biomass is to be included in the fish feed to replace 15 % of the fishmeal and 5 % of the soybean meal, the overall fish feed cost would be reduced by 6 %.