Thoughts on Algae Cultivation toward an Expansion of Aquaculture to the Scale of Agriculture

Today’s fish - dominated seafood consumption pattern cannot be sustained, since supply has shifted from capture to culture (each currently at around 100 million tons/y). Already today, seaweeds (macroalgae) and shellfish dominate mariculture. To prevent crises, wise policies could anticipate this inevitable shift, by promoting seaweed and shellfish production and consumption. The current rate of expansion in mariculture production will inevitably rise in the long run. Eventually, the seafood share in global food supplies, primarily in 3rd world countries, will rise, with the emerging global exhaustion of arable land and freshwater reserves. The sea remains the world’s last food frontier – the only environment that is still available for expansion of food production. A sustainable expansion of seafood culture by orders of magnitude necessitates a balance, as in agriculture, between fed aquatic animals (fish, shrimp…) and extractive plants and animals (bivalves, detritivores). Extractive organisms ameliorate the environmental impacts of the fed animals’ farming, while bringing more income and jobs. Cultured seaweeds, with their biochemical composition and high protein content, can also replace much of the fishmeal in aquaculture diets and provide humanity with nutritious protein.