Asian Journal of Biology

Industrial wastewater may alter the aquatic environment and influence physiological measurements in freshwater fish. This study descriptively assessed muscle-extract calcium values in the freshwater catfish Clarias batrachus following exposure to treated sago-industry effluent. Fish obtained from a supplier in Bangalore, India, were acclimatised for at least 15 days. Groups were subsequently maintained for 28 days in effluent-free water (control) or media containing 25%, 50%, or 75% treated effluent, with ten fish in each 20-L trough. Muscle samples collected after exposure were homogenised, centrifuged, and analysed for calcium using the o-cresolphthalein complexone colourimetric method. The reported calcium values were 4.4 mg% in the control and 5.5, 7.5, and 9.3 mg% at 25%, 50%, and 75% effluent, respectively. These differences represented descriptive increases of 25.0%, 70.5%, and 111.4% relative to the control. The reported values therefore increased progressively across the tested effluent concentrations. However, each concentration was represented by a single trough, and individual measurements, variability estimates, and independent experimental replicates were unavailable. Consequently, statistical significance and causation cannot be established. Furthermore, the analytical description does not provide sufficient information to interpret the reported units as calcium per unit mass of muscle. The findings identify a descriptive pattern requiring confirmation through independently replicated experiments, standardised tissue preparation, clearly defined reporting units, and appropriate statistical analysis.