Parametros físico-químicos da água em viveiros da esta o de piscicultura de Alta Floresta, Mato Grosso

The study was carried in Alta Floresta Fish Farming Estation of setember/2000 to february/2001, with additional collects in may and june/2001. Were monitored one dam (2,020m2), and five ponds (600 to 1,200m2). The physic-chemical parameters were measured near drainage systems, under depth 10 cm, daily the 08:00 hour and monthly achieved measured over 24:00 hour cycle, with interval of 04 hour between measurements: of water temperature; dissolved oxygen; pH. The temperature and oxygen were determined by oxymeter YSI-55, pH through pHmeter (Bernauer F-1002). The transparency was calculated by Secchi disc and total alkalinity determined by potentiometry titlemetry. Were applied fertilizers and calcareous, to estimate the relation among physic-chemical parameters and days growth, and evaluate the non-existence (I) and incidence condition (II) of aquatic macrophytes in the ponds. The water temperature varied of 21,7oC to 35,6 oC, the oxygen vary of 0,30 mg.L-1 to 10 mg.L-1 and pH between 4,7 to 8,9. The less valour were recorded 04:00 and 08:00 hours, with elevation 16:00 hour principally in December, possibly because high luminosity. The transparency maintained high in the dam (1,88±0,26 m), showed significant difference compared with the ponds (N=4, P<0,05). The alkalinity stayed significantly low (N=17, P<0,05) in the dam (16,01±0,63 mg.L-1), probably owing less amount of calcium salts, for the dam receiver not calcareous treatment. Water transparency can be considered indicator of the I and II condition, presented significant difference (P<0,05) in no 1 (N=15), no 2 (N=14) and no 3 ponds (N=19). For improve the growth condition suggest steadfast correction of pH, and studies about management of primary production to avoid phytoplancton blooms and incidence of aquatic macrophytes.