Analysis of six 24-hour series of zooplankton samplings across a tropical creek, the Port Reitz, Mombasa, Kenya
Season fluctuation in zooplankton abundance are described from six 24 hour series taken from the Likoni Ferry, using Clarke Bumpus net of 180 um mesh size. Two samples every 2 hours were taken at 2 months intervals from April 1985, to February 1986 inclusive.
Salinities were consistently above 30%o and surface water temperature varied between 24.0 and 28.9°C. Fifty-one taxa of zooplanktonic organisms were recorded in the samples. The mean total zooplankton abundance was 236m-3. The density of zooplankton was highest during the 24 hour series of the North-East monsoon season.
Actual mean abundance of plankton was relatively low during the 24 hour seires taken in South-East monsoon in April, June, August and October.
Holoplanktonic forms dominated the fauna, averaging 71% of the total plankton, copepods numbered 69% of the total fauna. The most numerous taxa amongst holoplanktonic forms were (in order of abundance): copepods, chaetognaths and appendicularia.
The most numerous amongst meroplanktonic forms were: molluscan larvae, fish eggs and brachyuran zoeae. The total zooplankton density for the night-time samples was higher than the day-time ones.
KEYWORDS: zooplankton, tropical creek, Port Reitz, occurrence, season, day, night, Kenya.