Determining oxygen consumption rate and asphyxiation point in Chanodichthys mongolicus using an improved respirometer chamber

Abstract

Knowledge of oxygen consumption rates and asphyxiation points in fish is important to determine appropriate stocking and water quality management in aquaculture. The oxygen consumption rate and asphyxiation point in Chanodichthys mongolicus were detected under laboratory conditions using an improved respirometer chamber. The results revealed that more accurate estimates can be obtained by adjusting the volume of the respirometer chamber, which may avoid system errors caused by either repeatedly adjusting fish density or selecting different equipment specifications. The oxygen consumption rate and asphyxiation point of C. mongolicus increased with increasing water temperature and decreasing fish size. Changes in the C. mongolicus oxygen consumption rate were divided into three stages at water temperatures of 11–33°C: (1) a low temperature oxygen consumption rate stage when water temperature was 11–19°C, (2) the optimum temperature oxygen consumption rate stage when water temperature was 19–23°C, and (3) a high temperature oxygen consumption rate stage when water temperature was > 27°C. The temperature quotients (Q10) obtained suggested that C. mongolicus preferred a temperature range of 19–23°C. At 19°C, C. mongolicus exhibited higher oxygen consumption rates during the day when the maximum values were observed at 10:00 and 14:00 than at night when the minimum occurred at 02:00.