Seaweed cultivation, as a diversification activity in mariculture, has tremendous potential all along the Indian coast. Seaweeds are rich in vitamins and minerals and are consumed as food in various parts of the world and used for the production of phytochemicals, viz., agar, carrageenan and alginate, which are widely employed as gelding, stabilising and thickening agents in several industries of food, confectionery, pharmaceutical, dairy, textile, paper, paint, etc.
In India, seaweeds are used as raw materials for the production of agar, alginate and liquid seaweed fertiliser (LSF). There are about 20 agar industries, 10 algin industries and a few LSF industries situated at different places in the maritime states of Tamil Nadu, Karnataka, Andhra Pradesh and Gujarat[1]. The red algae Gelidiella acerosa, Gracilaria edulis, G. crassa,
G. foliifera and G. verrucosa are used for agar manufacture and brown algae Sargassum spp., Turbinaria spp. and Cystoseira trinodis for the production of alginates and liquid seaweed fertiliser. The quantity of seaweeds exploited is inadequate to meet the raw material requirement of Indian seaweed industries. The GoI realising that the farmers have no facilities for production and processing of seaweed, farming of which is done majorly in Tamil Nadu and Gujarat coasts and around some parts of lakshadweep and Andaman and Nicobar islands, proposed a multi-purpose seaweed park to be set up in Tamil Nadu to promote seaweed cultivation as a part of Budget 2021[2].
Seaweeds such as Gracilaria edulis, Hypnea musciformis, Kappaphycus alvarezii, Enteromorpha flexuosa and Acanthophora spicifera can be successfully cultivated in long-line ropes and nets by vegetative propagation method. This activity has a potential to provide income and employment to about 200,000 families. To promote aquaculture and blue economy GoI has passed various policies and helped set up various organisations to impart required education and training to the farmers such as NPMF,PMMSY[3], NETFISH, and training by MPEDA[4]. Along with policies, technology also plays an important role in promoting the Blue Growth Initiative.