Effects of water temperature and pH on total suspended solids tolerance of Malaysian native and exotic fish species.
The aim of the present study was to investigate the effects of water temperature and pH on total suspended solids (TSS) tolerance of a native fish species, Barbonymus schwanenfeldii (Bleeker, 1854) and an exotic fish species, Oreochromis niloticus (Linnaeus, 1758) in Malaysia. The survival rates of both juvenile fish were tested in different TSS concentrations (0, 500, 1000, and 5000 mg L-1) at two water temperatures (27 and 29°C) and three water pH (pH 5, 6, and 7) for 21 days. The results showed that biotic and abiotic factors significantly influenced fish survival rate. The survival rate of juvenile fish significantly (p<0.05) decreased when they were exposed to warm and low pH water and high suspended solids. Moreover, the TSS tolerances of both juvenile fish in term of survivorship exacerbated at warm and low pH water. The O. niloticus juveniles were significantly (p<0.05) more tolerant to low water pH and high TSS than the B. schwanenfeldii juveniles. Nevertheless, the warmer water did not affect survival rate of B. schwanenfeldii juveniles significantly (p<0.05) more than that of O. niloticus juveniles. The present study demonstrated the potential negative impacts of water quality deterioration and biological invasion on the survival of Malaysian native fish in natural environment.