Algae and aquatic plants
The overall situation of algaculture is a paradox : aquaculture produces around 15 million tonnes of algae, but this is ten times more than the quantity harvested. Brown, red and green algae are all cultivated, as are other aquatic plants. These cultures produce vegetable protein, an essential part of the diet in many Asian countries, and extracts for use as food additives (gelling agent, preservative etc.) and in other industries (textiles, pharmaceuticals etc.).
A fair proportion of the aquatic plants other than algae are grown for use in aquariums.