Abstract:
The parasite fauna of the genus Puntius which has highest number of species, wide
distribution and some ornamental value was investigated with their parasite
infection levels. The study was carried out at the Akuressa area of the Nilwala
basin. Puntius species were collected from three localities of the area representing
different habitats. Live fish were caught using gape nets and gill nets and the
external and internal parasites of the fish were investigated, described and the
population levels were compared in order to find out the possible threatening
species on the survival of fish.
Eight Puntius species of the ten species available in the Nilwala basin could be
sampled. Parasites of wide variety of groupings, four species of monogeneans, one
species of digeneans, one cestodes species, two species of adult nematodes, one
species of crustaceans as well as the seven metacercarian species and two cestode
larval species were found in the survey. Due to the lack of parasite surveys in Sri
Lanka, most of the parasites found were new records to Sri Lanka. The four
monogeneans, Euclinostomum metacercaria, adult digenea, Bothriocephalus sp.,
Camallanus fotedari, Rhabdochona sarana and the Ergasilus sp. seemed to be new
record to Sri Lanka.
Of the parasites found, most were infecting more than one host species.
Metacercarians, larval cestodes, adult nematodes and the Ergasilus sp. were not
strictly host specific. Interestingly one monogenean species had loose specificity
infecting four host species. The two monogenean species, Dactylogyrus
crucilrabus and Dactylogyroides tripalhii, Cenlroceslus metacercaria, Diplostomid
metacercaria A & B, cestode larva Paradikpis scolecina and the nematode
Rhabdochona sarana are the parasite species more abundant in the Puntius species
of the area. The number of parasite species present on the host specific varied from
I - 6. P. jilamcntosus is the fish which was having highest number of parasite
species and densely populated by them. Puntius sarana was affected by gill
monogeneans. Puntius chola and Puntius amphibious were mostly affected by
Dactylogyroides tripalhii and Paradikpis scolecina. Puntius nigrofasciatus was
affected by Diplostomid metacercaria B the only parasite it is inhabiting. The other
fish species were not harboring high populations of the parasites.
