Seasonal variations in growth, reproduction, alginic acid, mannitol, iodine and ash contents of brown alga Sargassum wightii

169-175Growth of S. wightii Greville was maximum in winter months (October-December) correlating with salinity, rain fall and pH of seawater. Annual biomass production of 2.4 kg dry wt.m-2 was estimated. Reproduction occurred concurrently with peak growth period October-December. Rapid loss of axes followed with the end of reproduction. All chemical constituents showed seasonality and alginic acid and iodine contents showed correlation with growth in biomass and with each other. Based on the season for optimum growth together with that for alginic acid and iodine contents, harvesting of the alga is advocated from August to December for obtaining better product yield