Spatial and temporal variation in carrageenan yield and gel strength of cultivated Kappaphycus alvarezii (Doty) Doty in relation to environmental parameters in Palk Bay waters, Tamil Nadu, Southeast coast of India

Cultivated Kappaphycus alvarezii Doty (Doty) was analyzed for its dryweed quality (moisture and clean anhydrous weed (CAW) contents), carrageenan (semi-refined carrageenan (SRC)) yield, and gel strength with respect to environmental parameters (seawater temperature, salinity, nitrate, and phosphate) for 1 year from April 2012 to March 2013 from three different localities, viz., Mangadu, Munaikadu, and Vedalai, located in Palk Bay, Ramanathapuram District, Tamil Nadu, Southeast coast of India. Dryweed quality, viz., moisture content (35.00 +/- 0.00 to 38.39 +/- 0.19 %), clean anhydrous weed (39.26 +/- 1.37 to 45.22 +/- 0.57 %), and carrageenan (SRC) yield (33.30 +/- 1.23 to 38.50 +/- 0.20 to 0.30 %) with gel strength (379.05 +/- 6.07 to 486.44 +/- 5.57 g cm(-2)), was found to vary differently at all the sites during the study period. Two-way ANOVA showed that seawater temperature, salinity, and nitrate were significant spatially, while carrageenan (SRC) yield and gel strength were found to be significant (p = 0.05 level) both spatially and temporally. The carrageenan (SRC) obtained in this study met international specifications with respect to dryweed quality, carrageenan yield, and gel strength, suggesting its production indigenously for internal consumption as well as for export using the cultivated raw material and thus providing employment to the coastal rural people in India and earning foreign exchange.