Seasonal variation in seaweed biomass from the rocky shore of Pacha, near Karachi, Pakistan (Arabian sea)

The present study is based on the distribution and abundance of fresh and dry weights of seaweeds from the rocky ledge of Pacha. The study lasted for one year from April, 1993 to March, 1994. A total of 85 species of seaweeds collected. the abundant seaweeds were: Codium iyengarii, Iyengaria stellata, Sargassum latifolium, S. binderi, S. boveanum, Enteromorpha procera, Padina pavonia, Gelidium usmanghani, Colpomenia sinuosa, Valoniopsis pachynema, Jania capillacea, Caulerpa racemosa and Hypnea musciformis. Their highest fresh (42230.3 g/m raise to power is 2) and dry weights (21313.36 g/m raise to the power is 2) occurred in the low-tide zone. The latter zone supported the largest algal population. In winter maximum algal vegetation (58976.5 g/m raise to the power is 2) was noted and the peak growth (21854.1 g/m raise to the power is 2) of seaweeds was observed in January. The maximum biomass was contributed by brown seaweeds. The highest species diversity (2.05) occurred in August, and the highest Shannon-Weiner (0.46) and Evenness indices (0.97) were noted in November.