Harvest optimization to assess sustainable growth and carrageenan yield of cultivated Kappaphycus alvarezii (Doty) Doty in Indian waters

Abstract

Kappaphycus alvarezii (Doty) Doty, a carrageenan yielding red seaweed, was cultivated for a period of 1 year from April 2012 to March 2013 at Munaikadu in Palkbay waters of Bay of Bengal, Southeast coast of India. The experiments aimed to assess the ideal period for harvest among the different growth periods (15, 30, 45, 60, and 90 days) adopted to achieve sustainable growth (biomass yield or crop yield) as well as carrageenan (semi-refined carrageenan—SRC) content. Almost similar (higher) productivities and SRC yields with quality were obtained during 45 and 60 days growth periods. However, the income was more in 45 days (Rs.70708/-, US$ 1122.35) than in 60 days (Rs. 56,396/-, US$ 895.17) growth period. Considering productivity, total dry weed output, total revenue and net revenue per year, profit margin, carrageenan content, CAW content, and gel strength, 45 days growth period was found to be ideal among the different growth periods (15, 30, 45, 60, and 90 days). If the growers follow strictly 45 days growth cycle, they will benefit more and buyers will not be much affected. This study envisages that entrepreneurs and non-governmental organizations (NGOs) should raise awareness among growers for strictly enforcing 45 days growth period for commercial cultivation to obtain a sustainable crop yield with quality SRC.