Abstract:
Randenigala is a hill country reservoir, constructed for hydroelectric
power generation and irigation in 1982. Present paper deals with species
composition distribution and density of zooplankton in the reservoir based
on studies carried out from May to October 1992.
Twenty-four species of zooplankton were recorded from the reservoir,
out of which 12 species were rotifera, 8 species were c1adocera and four
species were copepoda. Copepoda density was the highest throughout the
investigation.
The total copepod population consisted mainly of 34% of calanoid
species, 6.7% of cyclopid species, 48.3% nauplii stages and 10.8% copepodid
stages.
Keretella tropica and Trichocera species formed more than half of the
rotifers. The next abundant species were the Brachionus fulcatus, Filina
opaliensis and Brachious caudatus. AspLanchopus and Lecane were very
rare.
Out of the eight species of c1adocera, Ceriodaphnia species was the
dominant group contributing more than 69% to the total Cladoceran community.
When the vertical distribution of zooplankton is concerned, the
average highest density of zooplankton was Observed above 10m depth and
highest numbers were generally recorded at surface waters. The densities
were low bellow 10m reaching lowest density in the hypolimnetic region.
