Seasonal variation of seaweed biomass in San Ignacio Lagoon, Baja California Sur, Mexico

During 1992-93, we sampled every three months at eight locations in San Ignacio Lagoon to evaluate the temporal and spatial variation of seaweed biomass. The red algae were the most abundant (79 %), followed by brown (13 %) and green (8 %) algae. We detected a general pattern of seasonal abundance, with a minimum biomass in spring (8.4 g m(-2)) and a maximum in summer (36.2 g m(-2)). Punta Choya had the greatest abundance (61.9 g m(-2)) and Los Medanos (0.05 g m(-2)) the least. The seasonal abundance pattern was different at each location because of differences in species composition. The most abundant species were Gracilaria pacifica, Spyridia filamentosa, Hypnea valentiae, Gracilariopsis lemaneiformis, Padina durvillae, Sargassum muticum, Sargassum sinicola, Gracilaria subsecundata, and Codium cuneatum, which together made up 85 % of the total biomass.