Effects of temperature, salinity, illumination and Cu2+ on oxygen consumption of juvenile Chinese sturgeon Acipenser sinensis

Abstract

The oxygen consumption rate (OCR) of juvenile Chinese sturgeon Acipenser sinensis (Body weight, range 5 - 32 g) were determined under different environmental conditions, including water temperature, salinity, illumination intensity and metal ion concentration [Cu2+] by single factor experimental analysis. OCR and opercula frequency (OF) increased with rising of water temperature. The linear relationships between water temperature (WT) and OF with OCR can be described as OCR = 0.018 WT + 0.016 (R2 = 0.988, p < /em> < 0.01), OCR = 2.737 OF + 77.726 (R2 = 0.64, p < /em> < 0.01), respectively. The acute exposure experiments showed that the OCR also increased initially with an increase in salinity. The linear relationships between salinity (S) and OCR can be described as OCR = 8.1 × 10-5 S3 – 3.01 × 10-3 S2 + 0.0263 S + 0.2729 (R2 = 0.995, p < /em> < 0.01). Three days of acclimation to different salinities, the OCRs decreased sharply relative to the first day exposure values. The equation OCR = - 6.29 × 10-4 S2 + 0.0238 S + 0.2797 (R2 = 0.988, p < /em> < 0.01) illustrates the linear relationship between salinity and OCRs after 3-day exposure. After 3-day acclimation, the OCRs increased also with increasing light intensity, except for the ambient light group (i.e., 2000 lx) and the group exposed to direct sunlight (i.e., 20000 lx). After 1-day exposure to different Cu2+ concentrations (C), the OCRs decreased rapidly in all of the groups. But the OCR level being gradually different with the increasing of Cu2+ concentration, OCR = 0.237e – 0.09 C (R2 = 0.898, p < /em> < 0.01). The results provided us with some useful guide lines which may apply into protection and cultivation management of this endangered species.