Zooplankton ecology in Kavaratti atoll, Lakshadweep, India

Abstract

Variations in physico-chemical parameters, zooplankton abundance, their
distribution, seasonal and diurnal variations in Kavaratti atoll, Lakshadweep
were studied for two years. The range of variation in water temperature was
27. 0-31.8°C, pH 7.1-8.4, diss. 02 2.2-7.5 ml/1 and salinity 33.0-35.3 ppt. with
the lowest values during monsoon. Day time zooplankton density was low (63-
1,987 no./m3) while it was high at night (1,404-5,762 no./m3). Density varied
betwen stations and over seasons. Substratum appeared to control the day time
density of drifting zooplankton. Density was the lowest during monsoon in day
time samples (202-359 no./m3) while it was the highest in night samples (4,275
no./m3) especially during the monsoon. Fish eggs and larvae (16-32.1 %) and
copepods (16.8-26.7 %) dominated in the day time samples, while decapod
larvae (26.8 %) and ostracods (20.6 %) dominated in the night samples,
zooplankton density was the maximum between 2100 and 0300 hrs and density
showed no definite relation with tide. The lagoon appeared to hold its own
zooplankton, which is distinct in character and response to physico-chemical
parameters.