Dynamics of some limnological characteristics in pacu (Piaractus mesopotamicus) culture tanks as function of handling

Abstract

In order to study the water quality in fish tanks, a 166-day (January to July 1992) experiment was realized using the indigenous species "p acu" (Piaractus mesopotamicus). Two different protein levels were tested in the diet (16% and 34% crude protein) and three stocking densities (0.25, 0.50 and 0.77 fish/m2). From the results, it was observed that the interactions between stocking density and experiment length affected the characteristics bicarbonate and alkalinity, as well as the interaction between stocking density and protein levels affected concentrations of free and total CO2, conductivity and pH (P < 0.05). The water temperature in tanks changed significantly during the period of study (P < 0.05),decreasing gradually from summer to winter. There was no significant difference in water residence time in the tanks (P < 0.05) during the experiment. The other limnological characteristics were not affected by treatments during study period.

Growth, yield, water and effluent quality in ponds with different management during tambaqui juvenile production

“…These values were higher than the ones obtained (5.1 to 8.7 µg L -1 ) in pacu ponds (Sipaúba-Tavares et al, 1999), and lower than the ones obtained during tambaqui grow out in highly fertilized ponds (296 µg L -1 ) (Teichert-Coddington, 1996). The results show that fertilization is an unnecessary procedure, mainly in ponds that receive fish ration.…”

“…Mean observed values were from 0.24 to 0.36 mg L -1 (Table 3), which is in the fish comfort zone (Boyd & Tucker, 1998). Sipaúba-Tavares et al (1999) found lower ammonia values (0.07-0.180 mg L -1 ) than the ones in the present work, in experiments with pacu, Piaractus mesopotamicus, probably due to the lower biomass. With higher biomass, Seok et al (1995) found ammonia values between 0.47 and 1.11 mg L -1 in channel catfish.…”

Survival, growth and metabolic parameters of silver catfish, Rhamdia quelen, juveniles exposed to different waterborne nitrite levels

“…Ammonia is the main nitrogenous waste material produced from amino acid catabolism; in water, ammonia is reduced to NO 2 -by nitrifying bacteria before its conversion into nitrate (Costa et al, 2004). The concentration of NO 2 -is usually low (0.03 -0.1 mg.L -1 ) in tropical fish culture systems with low stocking density (Sipaúba-Tavares et al, 1999;Andrade et al, 2007), but an imbalance in either ammonia production or NO 2 -conversion to nitrate can cause NO 2 -buildup (Jensen, 2003). High NO 2 -levels may develop in aquaculture systems due to high fish density (Hargreaves, 1998) or due to fertilizers added to the water (Lewis & Morris, 1986).…”

Effluent of a Polyculture System (Tilapias and Shrimps): Assessment by Mass Balance of Nitrogen and Phosphorus

“…When the quality of the pond water is poor it is common to occur an intensive increase of the water flow, thus reducing the residence time and consequently quickly releasing organic matter, inorganic salt, nutrients, plankton, among other components of the pond that might be damaging the production at that moment, therefore the flow control prevented the growth of phytoplankton [18]. The constant inflow and outflow in a short residence time and the uncontrolled management of rationing and supply water are some of the factors that directly influence the dynamics of nutrients.…”