Effects of Body Weight, Temperature, and Daily Time Periods on Oxygen Consumption Rate of Juvenile Silver Pomfret (Pampus argenteus)

Abstract

Oxygen consumption rate (OCR), which reflects the metabolism requirement of fish, is regulated by body weight and temperature. However, the priority of body weight and temperature in determining the OCR of fish is not clear. The optimal temperature and feeding time for the commercially important silver pomfret (Pampus argenteus) in China were evaluated using two sizes of fish (15.8 ± 2.7 g, S; 35.3 ± 6.1 g, L) at four different water temperatures (21, 24, 27, 30°C) and four time periods (5:00–6:00, 11:00–12:00, 17:00–18:00, 23:00–24:00) in static respirometers. The results showed that the OCR of fish was significantly higher at 21 and 24°C than that at 27 and 30°C (p < 0.05). The Q₁₀ increased from range of 21 and 24°C to range of 24–27°C but decreased from range of 24–27°C to range of 27–30°C. The body weight and water temperature significantly affected the OCR of fish (p < 0.05). The OCR of S was significantly higher than that of L (p < 0.05), while the OCR of fish increased linearly with increasing temperature. The OCR decreased with increasing fish body weight, and the coefficient (a – 1) in the linear regression equation of the logarithmic plot ranged from −0.568 to −0.191 (11.2–47.4 g, 21–30°C), with the mean value was −0.346. Overall, a two-factor regression equation for OCR of silver pomfret was established as OCR = 0.0558 × W –0.0081 × T + 0.0341 (N = 120, R² = 0.5626, p < 0.05). The OCR was relatively higher at 5:00–6:00 compared to other time periods of the day. These results suggested that body weight exerted a more significant influence on the metabolic rate of silver pomfret compared to temperature. The optimal temperature for this fish species was between 27 and 30°C based on Q₁₀, and the recommended feeding time was at 5:00–6:00 for maximizing growth for silver pomfret.