Seaweed Cultivation and Utilization

The earliest record of use of seaweeds dates back to 2700 BC in the compilation on ‘Chinese Herbs’ by Emperor Shen Nung. Reports show that seaweeds have been a part of the Japanese diet since 300 BC. Seaweeds are mainly eaten in the Oriental countries like Japan, China, Korea and more recently, in USA and Europe. The Republic of Korea has the highest per capita consumption of seaweeds in the world. After human food consumption, the next most valuable commercial use of seaweeds is as raw material for extraction of phycocolloids (agar, alginate and carrageenan), which are used in several industries. With 20,000 species of seaweeds in the world, India possesses 434 species of red seaweeds, 194 species of brown seaweeds and 216 species of green seaweeds. Traditionally, seaweeds have been collected from natural stocks or wild populations. However, these resources were being depleted by over-harvesting and hence, the need for their cultivation. Today seaweed cultivation techniques are standardised, perfected and made economically favourable. Besides, industry prefers a greater stability through sustained supply of quantity and quality of raw materials. In order to prevent overexploitation of natural seaweed habitats and to meet the needs of industry in an uninterrupted manner, nearly all brown seaweeds, 63 per cent of red seaweeds and 68 per cent of green seaweeds are being cultivated. Top five cultivated seaweeds in the world are Laminaria, Porphyra, Undaria, Eucheuma and Gracilari. These together account for 5.97 million metric tonnes of seaweed production. Top 10 countries producing seaweeds are China, Korea, Japan, Philippines, Indonesia, Chile, Taiwan, Vietnam, Russia and Italy. The current phycocolloids (seaweed gels) industry stands at over US$ 6.2 billion. The world production of commercial seaweeds has grown by 119 per cent since 1984 and presently, 221 species of seaweeds are utilised commercially including 145 species for food and 110 species for phycocolloid production.