The Influence of Water Quality on Molting Performance of Mud Crabs Fed Functional Diets and Administered Vitomol Injection

Abstract

This study aimed to evaluate water quality parameters in the soft-shell crab (Scylla olivacea) aquaculture conducted at the Educational Pond of Hasanuddin University, Barru Regency, South Sulawesi, during the period of May 6 to July 1, 2024. Observed parameters included temperature, pH, salinity, dissolved oxygen (DO), ammonia, and nitrite. Measurements were carried out directly in the field using calibrated instruments, with some parameters analyzed in the laboratory using a spectrophotometer. The results showed that temperature (26–30 °C) and DO levels (4–5 ppm) were within suboptimal ranges, potentially hindering metabolism and molting processes. Meanwhile, pH (7.5–8) and salinity (25–28 ppt) were within optimal ranges, supporting growth and osmoregulation. Ammonia concentrations (0.05–0.06 ppm) remained safe, whereas nitrite levels (0.30–0.34 ppm) approached critical thresholds, posing a physiological stress risk due to disrupted nitrification. Overall, while most parameters were within acceptable limits, potential risks from temperature fluctuations, low DO, and nitrite accumulation were identified. Therefore, consistent water quality monitoring and adaptive management practices are essential to maintain optimal rearing conditions for successful molting and growth of soft-shell crabs.