MARICULTURE OF ECONOMICALLY IMPORTANT AGAROPHYTES (GRACILARIALES, RHODOPHYCEAE) IN INDIA

Agar is a unique phycocolloid produced from the cell walls of red algal species belonging to the families: Gracilariaceae, Gelidiaceae, Pterocladiaceae and Gelidiellaceae (Armisen and Galactas 1987). Global agar manufacturing industries annually produce 14,500 metric tons of agar with market value of US$246 million from 125,200 dry tons of agarophytes and had a remarkable 70% growth  (Porse and Rudolph 2017). Among the agarophytes, genus Gracilaria alone shared 91 % of the raw material supply chain (i.e. 114,100 dry tons) annually (Porse and Rudolph 2017) for world's agar production.

In India, 26 agar factories are present. The total annual production of agar in India ranges between 100 - 132 t, utilizing about 880-1100 t of dry agarophytes and mostly for production of food grade agar. The available agarophytes resources from natural habitats are inadequate to cater to the needs of the local industry. Hence high quality agars are consequently expensive products. The gap between the demand and supply can be bridged through mariculture practices for seaweeds by cultivating the useful species on commercial scale. CSMCRI (Frontier research institute in seaweed research) developed successful cultivation technology-Floating Bamboo Raft culture method for year round cultivation of three economically important agarophytes Gracilaria debilis, Gracilaria dura and Gracilaria edulis to meet out agar industries raw material demand. Mariculture of all three agarophytes showed daily growth rate 3.5% day^-1 and fulfilled global standard growth rate value (3.5% day^-1) recommended for mariculture of seaweeds.