Low-cost, high-quality algal biomass for aquaculture feed

Aquaculture provides half of all the seafood consumed by humans, and this is predicted to rise to two-thirds by 2030. The UK Government considers aquaculture vital to meet the needs of consumers for a sustainable seafood supply ('Planning for sustainable growth in the English aquaculture industry', DEFRA, 2012). As the fastest-growing sector of agriculture, with the lowest carbon footprint of all the animal production industries, the expansion of aquaculture also presents challenges.

One of the biggest issues facing the sector is nutrition – almost 60% of operational costs in salmon farms are feed supply (Marine Scotland, 2014). Fishmeal and fish oil in feeds are a key constraint, with their production stagnating over the last decade.

A new source of sustainable raw material suitable for aquafeeds is needed to increase aquaculture health without relying on declining and stagnant catches of wild-caught fish from reduction fisheries.

Algae is considered a promising protein source for use in aquafeeds, but its inclusion in industrial-scale feed production is difficult due to production scale-up limitations in technology and strain optimisation, which results in low volume availability and production costs which make algal meals prohibitively expensive. Algal biomass is a high-nutrient biomass that is beneficial to fish growth, health, and final food product quality. Dr Daniel Merrifield worked with Feed Algae Limited to:

The project replicated natural algal 'blooms' on land in Morocco – the process where nutrient-rich seawater and replicating upwelling events where microalgae are exposed to new nutrients after storms, winds, and currents. Several strains were produced and examined to determine the best performance and nutritional quality.