World Market

About 10 million tonnes of seaweeds (wet weight) are produced world-wide each year.

Brown algae accounted for 7 million tonnes, of which Chinese production alone of the food kelp Saccharina japonica is just below 5 million tonnes, making it the largest single-species crop produced by aquaculture in the world.

About 300,000 tonnes of this material is used in China to make about 10,000 tonnes of alginates, viscous polysaccharides used in a wide variety of industrial applications, particularly in the food industry. In addition, Japan and Korea produce about 21,000 million sheets of nori (about 550,000 wet tonnes ). Nori is a red alga (mainly Pyropia yezoensis formerly Porphyra yezoensis), and this crop is worth about US$1.5 billion, the most valuable single-species crop produced by aquaculture in the world.

The third most valuable food species is wakame (Undaria pinnatifida) of which 750,000 tonnes were produced in Japan, Korea and China in 1995.

Most of the remaining seaweed harvesting and aquaculture goes to fuel the production of the three families of seaweed polysaccharides known as seaweed gums: alginates from brown algae, and carrageenans and agars from red algae.

The wholesale value of these gums is about US$950 million. The total worth of the international seaweed business exceeds US$6 billion.