Biomass production of two Sargassum species at Cape Rachado, Malaysia

Seasonality in biomass production of Sargassum baccularia (Mertens) C. Agardh and Sargassum binderi Sonder ex 1. G. Agardh was analysed based on quarterly destructive sampling using a line transect-quadrat method from January 1995 to April 1996. Biomass for both Sargassum species showed an unimodal pattern. S. baccularia attained high biomass during January 1995 (520.23 g wet weight m-2, 47.88 g dry weight m-2 , 13.35 g ash-free dry weight m-2) and July 1995 (501.98 g wet weight m-2, 64.92 g dry weight m-2, 14.00 g ash-free dry weight m-2). S. binderi attained the highest biomass in April 1996 (656.13 g wet weight m-2, 80.81 g dry weight m-2, 15.25 g ash-free dry weight m-2) with another high value recorded in July 1995 (429.28 g wet weight m-2, 54.30 g dry weight m-2, 11.20 g ash-free dry weight m-2). Both Sargassum species recorded the lowest biomass in January 1996 (S. baccularia: 76.14 g wet weight m-2 , 9.97 g dry weight m-2, 1.97 g ash-free dry weight m-2 ; S. binderi: 68.21 g wet weight m-2, 8.36 g dry weight m-2, 1.68 g ash-free dry weight m-2). Biomass for both Sargassum species was strongly correlated to the thallus length. The population of both Sargassum species consisted mainly of young plants with 96% of the S. baccularia population and 89% of the S. binderi population being shorter than 199 mm. Both Sargassum populations recorded low percentage of fertility. The most important factor that controlled the biomass production and reproduction for both Sargassum species was rainfall.