Investigating the feasibility and conditions for outdoor microalgae cultivation in Seychelles

Microalgae play a critical role in aquaculture hatcheries as a primary feed source, supplying lipids, proteins, and vitamins to nearly all aquaculture species. Traditionally cultivated indoors under controlled conditions, microalgae production is resource intensive. This study examines the potential for outdoor microalgae farming in equatorial regions like Seychelles, utilizing abundant sunlight and stable high temperatures for a more cost-effective, sustainable approach. By minimizing the reliance on sophisticated facilities, this approach can increase accessibility for a broader range of aquaculture practitioners. This research investigates the feasibility of outdoor cultivation and seeks to identify optimal light and temperature conditions for growing Tetraselmis spp. and Chaetoceros muelleri, chosen for their hardiness and importance to various aquaculture species. A factorial experimental design was employed with four treatments: shaded, unshaded, cooling system, and non-cooling system, alongside an indoor control. The results indicated that C. muelleri reached the highest cell density of 887,000 cells/ml in the unshaded-cooled treatment (24.4°C to 34.4°C). Whereas Tetraselmis spp. achieved peak cell density of 159,000 cells/ml indoors at 28.9°C, though unshaded-cooled outdoor treatments may also support growth, pending further investigation. The research seeks to determine the feasibility and optimal growing conditions for outdoor microalgae production in Seychelles and similar climates.