Phenology of Sargassum spp. (Sargassaceae, Phaeophyta) from Reunion Rocks,KwaZulu-Natal, South Africa

The density, standing stock, reproductive periodicity and alginate yields h ave been investigated for a mixed Sargassum species population at Reunion R ocks, KwaZulu-Natal, South Africa. The population consists of two dominant components, Sargassum elegans Suhr and a second species, here termed Sargas sum sp. 1. Sargassum elegans typically makes up more than 70% of the popula tion which is heterogeneous in both biomass and density distribution. These species share the same macro-scale distribution within the site and displa y the same periods of growth and senescence. Standing stock dropped in the cooler winter months and reached a maximum in the hot summer months. Biomas s was correlated to one month antecedent minimum, maximum and mean air temp erature. Density patterns followed a similar pattern and biomass increased with density. Alginate yield of both species peaked in the warm summer mont hs and was lowest during the cooler winter months. Reproduction peaks were recorded in the cooler months after the peak in biomass and density.