Diatom-assisted aquaculture: Paving the way towards sustainable economy

With decreasing world oceans fish stock there is rapid increase in aquaculture production. To meet this demand, there is an urgent need to improve existing aquaculture technologies and make the system more sustainable and economically feasible. Diatoms are unicellular protists that are present ubiquitously in freshwater and marine habitats and are responsible for 40% of marine and 20% of net global primary productivity. They are the most preferred microalgae for production of live feeds in mariculture due to their suitable size, easy digestibility, and optimum nutritional content. Diatoms biosynthesize a range of bioactive compounds like lipids, polysaccharides, proteins, pigments, and vitamins which can both promote the health and survival of aquatic species like fishes, bivalves, and shrimps. As the main prerequisite to attain sustainability is to reduce pollutants from aquaculture wastewater, diatoms have long been employed for remediating and utilizing the eutrophic nutrients as a growth supplement which otherwise might be detrimental to aquaculture species. Though many recent studies have highlighted the significance of diatoms in aquaculture, its dual contribution in maintaining the nutritional content of the feed as well as in improving the water quality should be coupled with its unique mechanisms and adaptability. Thus, the current review addresses the bottlenecks in aquaculture industry and the prospects of implementing diatom-based bioremediation and biomass valorization for the production of live feeds with the hindsight of establishing circular bioeconomy.