However, regardless the climatic period and according to recent studies, Itans reservoir can be classified as hypertrophic regarding the levels of total phosphorous and chlorophyll-a (COSTA et al., 2009).
Of the seven samplings carried out in 2008 in the Itans Reservoir, the number of protozoa was greater at point 1 in four of them, mainly during the dry season.
The Itans Reservoir presented non-standard results for both biological and physical-chemical variables throughout the study year.
Mean values and standard deviations of physical -chemical variables and concentrations of chlorophyll-a and total phosphorous in the Itans reservoir, in 2008.
Water temperature exceeded 32 [degrees]C in Passagem das Trairas, Itans, and Sabugi reservoirs, and in Armando Ribeiro Goncalves reached 34 [degrees]C in March 2004, during the rainy season.
Chlorophyceae and diatoms showed more prominent biovolume values in Itans, Parelhas, and Sabugi reservoirs (>10 [mm.sup.3].[L.sup.-1]).
tropica, Brachionus havanensis, and Keratella americana dominated the zooplankton community in Itans, Passagem das Trairas, and Sabugi reservoirs.
Maximum zooplankton densities (>600 Ind.[L.sup.-1]) were observed in Itans, Passagem das Trairas, and Sabugi reservoirs, while lowest densities were observed in ARG and Parelhas (maximum of 235 Ind.
The second group included Gargalheiras, Itans and ARG, with zooplankton densities near 400 ind Ind.[L.sup.-1] and a quantitative dominance of selective filter-feeders (copepods over rotifers).
The Boqueirao Parelhas, Gargalheiras, Itans and Passagem das Trairas reservoirs all showed temporal variation in trophic condition, with Chl a concentrations below 12 [micro]g.[L.sup.-1] during September and December, and are classified, during this period, as mesotrophic.