Relationship between pH, water temperature, dissolved oxygen and parasitic infestation of freshwater fishes in Temengor, Bersia and Chenderoh Reservoirs, Perak, Malaysia

Abstract

Fishes in the reservoirs are subjected to many parasitic diseases due to poor quality of water and large-scale mortality is seen in the fish population due to parasitic diseases. There were no documented reports relating to fish parasite interactions with abiotic factors of freshwater fish parasitism in Temengor, Bersia and Chenderoh reservoirs. Fish were examined for parasites using standard parasitological techniques. Three in-situ replicates of physico-chemical parameters were taken at each sampling period from the reservoirs. Dissolved oxygen (DO) concentration (mg/L), temperature (°C), and pH of the reservoirs were recorded using YSI 556 Multi-Probe Meter. The correlation of physical parameters with fish parasites showed that only protozoan cyst (DO: r = 0.806, P < 0.05) and Acanthocephalus sp.(DO: r= 0.959, P < 0.05) showed a significant positive correlation with DO. Unidentified protozoan cysts, Acanthocephalus sp. and Dactylogyrus sp. 2 D. hamacopulus, Dactylogyrus sp. 3, and Paradiplozoon barbi. Acanthosentis sp., Ergasilus sp., D. dolichoirri, unidentified adult trematode, unidentified larval trematode, Lamproglena sp. 2, Gyrodactylus sp., unidentified nematode, and unidentified copepod showed a relationship with pH, DO, and temperature, while others do not. Majority of the parasites weakly correlated with physical water parameters due to the irregular measurement of water quality of the reservoirs during the study. In conclusion, the value of pH, DO and temperature recorded in this study is suitable for fish survival. This research revealed that Unidentified protozoan cyst and Acanthocephalus sp. showed a significant positive correlation with DO values of the reservoirs along Perak River.