Temporal and spatial variation of frondose benthic seaweeds in La Paz Bay, B. C. S., Mexico

To evaluate the temporal and spatial variation of the marine algal biomass present during 1993, we systematically sampled ten sites every three months in La Paz Bay. The sampling was made using two 200-m lines perpendicular to the coast. The samples were taken every 10 m along both lines, using a square meter as the sampling unit. The total biomass had a monodal cycle with the maximum in spring and the minimum in winter. The distribution of biomass showed differences between locations; Punta Leon and El Malecon had exceptionally high biomass whereas at Isla Gaviota the recorded biomass was very low. At Tarabillas, San Juan de la Costa, Isla Gaviota, San Gabriel, Gallo Gallina, and Ensenada Grande, the maximum biomass was in summer: Spyridia filamentosa was the species that contributed the most to the biomass at these places. At Punta Leon, El Malecon, and Calerita, the greatest biomass was in spring: Sargassum sinicola and S. herporhizum were the species that contributed most. At El Comitan the maximum biomass was in autumn and the largest contributor was Caulerpa sertularioides.