More than 50% of the world's seaweed crop is produced on farms

World production of commercially dried seaweed is more than two million tons.
More than half of this production is from seaweed farms, mostly in East Asia and Southeast Asia.
Seaweed farming is among the most sustainable of aquaculture technologies.
Seaweed farming is a wholesome form of occupation that provides economic opportunities in coastal areas where economic opportunities are often limited

Farming of seaplants and harvesting of wild seaplants are important sources of income to coastal peoples all over the world. This human face of seaplant industries is one the aspects of the business that gives it fascination. Except for the large kelp harvesters of southern California and Baja California most seaweeds are grown or are harvested from wild stocks using very hands-on techniques. Seaplant production tends to employ people in large numbers and has a large multiplier effect in communities where is is significant. In some areas such as the southernmost islands of the Philippines seaplant farming and the seaplant trade is one of the foundations of the whole economy.Production capacity of the Farming and Harvesting Community is well illustrated by these points:

Farming of Kappaphycus (cottonii) and Eucheuma (spinosum) is undertaken in several countries including the Philippines, Indonesia, Malaysia, Tanzania, Kiribati, Fiji and Madagascar, total market volume now exceeds 140,000 commercially dried tons per annum at a value of over 70 M USD.
The valuable Porphyra (Nori) industries of China, North Korea, South Korea and Japan are based on farming activities that produce over 130,000 tons of harvest with a high average unit value worth a total of over over 2.5 B USD.
Manually harvested wild genera such as Chondrus, Furcellaria, Gigartina, Iridaea, Mastocarpus and Tichocarpus are also mainly produced as carrageenan raw materials, producing countries include Argentina, Canada, Chile, Denmark, France, Ireland, Japan, Mexico, Morocco, Portugal, North Korea, South Korea, Spain, Russia and the USA, production exceeds 25,000 dry tons valued at more than 20 M USD.
Most of the world's production of agar-bearing seaweeds is still harvested from wild stands. Genera include Ahnfeltia, Gelidium, Gelidiella and Gracilaria and Pterocladia. Gracilaria farming is achieving important levels with about 50,00o tons of the ca. 90,000 ton total being farmed. Strides are also being made on the farming of the highly valued bio-agar sources Gelidium and Gelidiella. Producing countries include Argentina, Canada, Chile, China, France, India, Indonesia, Japan, Madagascar, Mexico, Morocco, Namibia, New Zealand, Peru, Portugal, Russia, South Africa, Spain, Thailand, and the USA, production exceeds 110,000 tons valued at more than 100 M USD.
Farming accounts for most of the production of brown seaweed genera such as Hizikia, Laminaria and Undaria. These are important human food genera as well as being sources raw materials for production of biopolymers (alginates) and agriculture products. Producing countries for farmed and wild crops of these genera include Argentina, Australia, Canada, China, Chile, France, Iceland, Ireland, Japan, North Korea, Norway, Portugal, South Africa, South Korea, the UK, and the USA . Cultivated (wild) production is about 6,300 (1,200) tons of Hizikia, 673, 000 (58,000) tons of Laminaria, and 102,000 (20,000) tons of Undaria.