Study of fish fauna in the streams of Oliyagankele forest reserve and in Lenabatuwa tank

Abstract

Sri Lankan biological diversity is concentrated in a small land mass, among the global biodiversity rich countries. It has a remarkable variety of life both in terms of fauna and flora. Sri Lanka is the home for thirty-two endemic fresh water fish species. Aquarium trade, private collectors, laboratory experiments and gene banks of developed countries create a high demand for Sri Lankan fresh water fishes. Oliyagankele forest reserve and Lenabatuwa tank are situated in the Matara district. Investigations were carried out over a period of 04 months (May 2004 to August 2004) at 04 sites located in two streams and 02 sites of the tank, to find out the currently occurring fish species, their distribution pattern, and the influence of physico-chemical parameters on the fish distribution. FBI (Family Biotic Index) value was calculated for the two streams and the tank separately. The overall check list consisted of twenty nine fish species and among them were six endemic species. The FBI value calculated for the Lenabatuwa tank (6.9) indicated poor water quality, while the stream 2 revealed a fair water quality with an FBI value of 5.20 and stream 01 exhibited the best water quality with a FBI value of 3.36. According to the statistical analysis of Pearson’s correlation, most families and genera (except family Heteropneustidae and Channidae, genus Channa, Pseudosphromenus and Puntius) are found to be significantly correlated with different physico-chemical parameters. The Student- Newman- Keuls test revealed that the mean values of physico-chemical parameters such as temperature, DO, BOD, COD, phosphate concentration and the conductivity were significantly different (P < 0.05) among sites while pH and the nitrate concentration were not significantly different site wise.