Impacts on ocean depletion from algal biofuel production

Algae biofuel is typicall produced from algal oil, resulting in a co-product of biomass residuals rich in protein and carbohydrate. These co-products can be used as high quality feed and food additives, contributing to the... [ view full abstract ]

Algae biofuel is typicall produced from algal oil, resulting in a co-product of biomass residuals rich in protein and carbohydrate. These co-products can be used as high quality feed and food additives, contributing to the food sector when used for human nutrition, animal feed, fishmeal and even as fertilizers. Fishmeal is an essential protein source of aquatic feeds. Studies have shown that fishmeal can be replaced by algae biomass residuals in the feeds of salmon, crap and shrimp, with essential nutrients promised for fish and human health. In current aquaculture systems, fishmeal is primarily made from forage fish, processed fish bones and fish by-products. If the essential nutrients from conventional fishmeal can be provided by algae-based fish feed, additional supply of fish feed by co-products from algal oil production will substitute for materials from wild capture fisheries in proportion with their nutrient content or market value. The substitution could potentially avoid cultivation and fish-catching, and therefore reduce withdrawals and related impacts on ocean ecosystems.   

The indirect impacts from algal oil production systems can be treated similarly to the indirect land use changes (iLUC) impacts that result from terrestrial crop biofuel production, but the effects occur in the context of ocean resources instead of terrestrial resources. Although consequential iLUC effects caused by energy crops such as corn, soybean and sugarcane have been well studied, the indirect effects from microalgae cultivation and co-products produced from microalgae biofuels have rarely been discussed, such as the consequential effects on aquaculture and fisheries.

This study aims to evaluate the consequential impacts on ocean resources induced by co-products from algal oil production systems using a cause-effect method. Different scenarios with different substitution rates between marine fishery and fishmeal from microalgae will be tested given the maximum yield of algal oil production in the US. The study will answer the following question: What is the area or measure of a marine fishery that could be displaced by fishmeal substitution from algal oil production systems? The productivity of marine fisheries, environmental impacts from marine fish capture, quality and quantity of fishmeal produced from microalgae, substitution potentials and ecological consequences are investigated.