SPATIAL DISTRIBUTION OF MONOGENEANS AND THEIR PREVALENCE IN TWO FRESHWATER FISH SPECIES IN RELATION TO SOME PHYSICOCHEMICAL PARAMETERS OF KENYIR LAKE, MALAYSIA

Abstract

A parasitological investigation was carried out on two freshwater fish species - Hampala macrolepidota andHemibargrus nemurus (n = 460) for gill monogeneans from four stations in Kenyir Lake [station 1-Kiang River (5"6'49.47"N, 102"44'36.60" E); station II- Petang Island (4"58'35.65" N, 102"47'3.74" E), station III -Ketiar River (5"3'48.38" N, 102"34'14.70" E) and station N -Tanjung Mentong (4"48'36.54" N, 102"45'40.56" E)]. Four monogenean parasites were detected viz: Biforr:ohaptor baungi and Cornudiscoides malayensis from the gills of Hemibargrus nemurus; Dactylogyrus quadribrachiatus and D. macrolepidoti from gills of Hampala macrolepidota. Their spatial distributions on the host gills are reported. The prevalences ofthese parasites were correlated to physico-chemical parameters (temperature, dissolved oxygen, pH, ammonia, nitrite, and alkalinity) of the lake water. The results revealed that all the stations were infected, but the highest infestation was in the third station (Ketiar River) with 1000/o prevalence and intensity of 43 individual worms per host Correlation between physico-chemical parameters and parasites prevalence shows statistical significance (P < 0.05), especially between prevalence, mean intensity and total ammonia nitrogen (TAN). In conclusion, monogeneans from these two fish species were not randomly distributed but showed site specificity.