Successful establishment of commercial farming of carrageenophyte Kappaphycus alvarezii Doty (Doty) in Sri Lanka: Economics of farming and quality of dry seaweed

Abstract

Kappaphycus alvarezii seed material was brought from Malaysia in 2011 to initiate cultivation in Sri Lanka. After conducting trial cultivation, the results were found encouraging and commercial farming was started in mid-2012 at Valaipadu village. The average daily growth rates (ADGRs) using bamboo raft method were varied from 3.44 ± 0.12 to 4.45 ± 0.85% in 2014 and 3.47 ± 0.33 to 4.51 ± 0.58% in 2015, whereas using the monoline method, the same were 2.99 ± 71 to 3.95 ± 0.55% in 2014 and 2.44 ± 1.14 to 4.22 ± 0.37% in 2015. ADGR% decreased with increasing seawater temperature (p = −788, r = 0.01) and was positively correlated with water motion (p = 820, r = 0.001). The average monthly production of dry seaweed of a family of three members was 1359 to 1800 kg, and their monthly income ranged between US$465 and 615. The qualities of dry weed produced in 2014 in terms of moisture, clean anhydrous weed, soluble salt, impurities, and C/s ratio were 34.20 ± 3.47, 40.18 ± 3.77, 25.04 ± 2.39, 0.56 ± 0.46, and 1.42 ± 0.35, respectively, whereas in 2015, the values were 34.08 ± 1.81, 39.20 ± 3.62, 25.24 ± 1.90, 1.44 ± 0.50, and 1.46 ± 0.37%. The yield of SRC manufactured at commercial level was 34.64 ± 2.36% and its water and KCl gel strengths were 430 ± 147.88 and 871 ± 166.30 g cm−2, respectively. The absorbance of SRC sample at 1257, 1074, 929, and 846 cm−1 in IR spectrum confirms that it was a kappa kind of carrageenan. Results of commercial cultivation of K. alvarezii in the present investigation showed that Sri Lanka has good potential to create additional income for coastal people through its farming and produce quality dry weed for the carrageenan industries.