High Stocking Density Impairs Mineral Content of Brown Trout

The aim of the present study was to determine the effects of high stocking density on mineral content of muscle and liver in brown trout. Juvenile fish were stocked in experimental tanks as triplicates for 90 days. Initial stocking density was 10 kg m-3 for control and 50 kg m-3 for high stocking density group. Atomic absorption spectrophotometry was used for the indication of mineral concentrations. Stocking density was calculated by dividing the weight of the fish in the tank water volume (kg m-3). The average values of P, K, Mg, Na, Ca, Fe, Zn, Cu, and Mn were found 2012.3, 958.0, 560.0, 506.1, 60.3, 31.5, 10.6 1.61 and 0.27 mg kg-1, respectively, in muscle of fish reared high stocking density and the values for same minerals were found 2463.6, 1594.8, 866.2, 762.5, 155.7, 65.0, 20.0, 1.96, and 0.37 mg kg-1, in muscle of control group. However, P, K, Mg, Na, Ca, Fe, Zn, Cu, and Mn values were 1612.3, 1501.1, 530.0, 266.8, 129.2, 52.7, 0.82, 0.32, and 0.12 mg kg-1 in liver of fish reared in high stocking density and 2270.4, 2063.6, 1300.8, 644.6, 189.6, 80.1, 1.59, 0.39 and 0.24 mg kg-1 in liver of control group. It was concluded that that overcrowded condition causes to decrease amount of liver and muscle mineral content in brown trout.