Feasibility of Gracilaria dura cultivation in the open sea on the Southeastern coast of India

• To ascertain feasibility of cultivation of Gracilaria dura in the open sea
• Assessing yield and growth by various techniques to select the best method aimed at commercial farming
• To arrive at projected cost of production to determine potential earnings
• To establish likelihood of agarose extraction from farmed materials
• To bring in second candidate species for commercial seaweed farming along the Southeastern coast of India.

Gracilaria dura is the industrially potential agarophyte for commercial cultivation in India. Five different cultivation methods namely, floating bamboo raft, poly propylene net, net bag, hanging rope technique and net pouch were investigated for their suitability to undertake farming in the open sea. Among these, polypropylene net method yielded highest biomass (1.764 ± 0.82 kg fr.wt m− 2) with corresponding daily growth rate (DGR) of 3.748 ± 0.91% day− 1, followed by floating bamboo raft (1.05 ± 0.39 kg fr.wt m− 2, 2.61 ± 0.45% day− 1) and net bag (0.904 ± 0.57 kg fr.wt m− 2, 3.17 ± 1.16% day− 1) methods respectively. The projected earnings were higher (US$ 529 month− 1 ha− 1) for net method than other techniques tested, which was attributed to low labor requirement, ease of maintenance, and reduced seedling loss coupled with high growth rate.