Cyanobacteria are widely distributed in eutrophic environments, such as fishing ponds, where they can generally form toxic blooms. The objective of this study was to assess the biodiversity of the Cyanobacteria in ten fishing ponds in São Paulo Metropolitan Region (RMSP). The samples were collected from the sub-surface, horizontally towed with a plankton net, in two periods: September/October 2001 and February/March 2002. The samples were preserved in formaline:seawater at 4-5%, and studied under a photonic microscope. Twenty-three species of cyanobacteria belonging to five orders, seven families and 15 genera, were identified. The richest order was Synechococcales (8 species), followed by Chroococcales (6 species), Pseudanabaenales (5 species), Oscillatoriales (2 species) and Nostocales (2 species). Aphanocapsa Nägeli and Microcystis Kützing ex Lemmermann were the most representative genera, with five and four taxa respectively. 22% of the total were considered frequent species, 35% infrequent species, and 43% rare species. Aphanocapsa annulata G.B. McGregor, Aphanocapsa delicatissima W. West & G.S. West, Aphanocapsa incerta (Lemmermann) Cronberg & Komarek, Aphanocapsa holsatica (Lemmermann) Cronberg & Komarek and Microcystis aeruginosa (Kützing) Kützing occurred in seven fishing ponds. This is the first citation of Aphanocapsa annulata for the state of São Paulo.
biodiversity; Chroococcales; eutrophication; taxonomy
