Seasonal Biomass Dynamics and Zygote Cultivation of Sargassum aquifolium on Different Substrates in the Red Sea

Sargassum aquifolium(Turner) C. Agardh is one of the most abundant and widely distributed seaweed species in the Red Sea. This study examined the seasonal fluctuations in biomass and evaluated the effectiveness of zygote cultivation on various substrates, including interlock stone, cement stone, limestone, and nylon string. The findings indicated significant seasonal variations in biomass, with peak growth observed in summer, reaching 828±70gm.m² of fresh weight. The success of zygote attachment and growth varied by substrate, with recruit density highest on cement stone, followed by interlock stone, and then limestone over a five-month observation period. Germlings exhibited a higher daily growth rate (DGR) on cement stone at 56, 112, 140, and 168 days. Young juveniles showed a consistent increase in length up to 168 days post out-planting, with some fluctuations. These insights are crucial for developing sustainable aquaculture practices for Sargassum aquifolium, guiding substrate selection, and improving productivity in the Red Sea.