Commercial Farming of Kappaphycus alvarezii in Sri Lanka: Current Developments and Opportunity for Becoming a Major Carrageenophyte Producer

The current annual world production of Kappaphycus alvarezii is approximately 200,000 metric tonnes, and its value-added product carrageenan is approximately 60,000 t. Kappaphycus alvarezii has been farmed successfully since 2012 in Sri Lanka. Over 250 fisher folks from 3 districts, viz., Mannar, Kilinochi, and Jaffna, are currently involved in farming for their livelihood. Floating bamboo rafts and monolines, the two popular cultivation methods, were adapted, and the percentage average daily growth rate (ADGR%) of K. alvarezii over 45 days with 150 g of seed propagule across different locations with respect to seasons was 3.50 ± 0.50. The average monthly production of dry seaweed of a cultivator was 450–550 kg with a monthly income of 150–225 USD. The quality of dry seaweed, such as moisture (35 ± 3.0%), clean anhydrous weed (CAW 38 ± 5.0%), soluble salt (28 ± 3.0%), and impurities (< 1.0%), was comparable to the quality of commercial material. The yield of SRC was 30 ± 3.0%, whereas that of refined carrageen was 25 ± 2.5%. The average potassium and water gel strengths of the SRC were 600–950 g cm−2 and 250–450 g cm-2, respectively, and the milk gel strength was 90–150 g cm−2. Kappaphycus alvarezii farming has been introduced to over 25 countries over the last 35 years. However, only five to seven countries produce commercial volumes (over 1000 t/year) for the carrageenan industry today. Sri Lanka has recently been added to the list of countries farming K. alvarezii, and it is estimated that it has the potential to produce over 25,000 t dry weed per year; therefore, there is a huge opportunity to develop carrageenan industries in Sri Lanka. The current status of farming of K. alvarezii, scope for expansion, and opportunity to develop carrageenan industries in Sri Lanka are discussed.