Relationship between climatic and abiotic parameters and the reproductive period of Macrobrachium birai Lobao, Melo & Fernandes and M. petronioi Melo, Lobao & Fernandes [Decapoda, Palaemonidae] of Branco River [Cananeia - SP - Brazil]

In order to determine relationships between the reproductive cycles of Macrobrachium birai and M. petronioi population and the climatic periodism of the region and the behaviour of some limnological characteristics of the water of Branco River (Itapitangui - Cananeia - SP), 24 degree 54'44"S and 47 degree 58'30"W, biological aspects of the two especies and physical and chemical data of the water were recorded during the period of October/85 to March/88, through monthly samplings. The median values of the limnological characteristics were as follow: water temperature 22.0 degree C; water layer 57.7 cm; pH 6.8; color 50 mg/L; turbidity 4.9 FTU; conductivity 75 mu S/cm; alkalinity 24.23 mg/L CaCO sub(3); ammonium 0.20 mg/L; nitrite 0.6 mu g/L; nitrate 0.09 mg/L; phosphate 30 mu g/L; silic 6.48 mg/L; total hardness 20.83 mg/L CaCO sub(3); calcium 3.37 mg/L; magnesium 3.0 mg/L; iron 0.48 mg/L; chloride 9.53 mg/L; dissolved oxygen 8.06 mg/L O sub(2); oxygen saturation 96%; oxidability 3.13 mg/L; bicarbonate 29.58 mg/L; total carbon dioxide 29.02 mg/L and free carbon dioxide 7.73 mg/L. It was also observed that M. birai presents nocturnal rhythm and reproduces during the summer when the values of some characteristics of water such as conductivity, alcalinity, total hardness and bicarbonate tend to diminish, and that M. petronioi has diurnal rhythm and reproduces in spring when the above parameters tend to have their values increased. (DBO)