Composition, Abundance and Seasonality of Zooplankton in Mida Creek, Kenya

Samples were collected monthly at four fixed stations in Mida creek from May 1996 to April 1997, in order to determine the species composition, abundance and diversity of phytoplankton and zooplankton collected with 20and 332-μm mesh size plankton nets respectively. Sampling also included measurement of salinity and temperature. Peaks in phytoplankton abundance occurred in May and January, following the long rains in April–May and the short rains in November–December. Zooplankton densities followed the phytoplankton peaks with the main peak occurring in February after the major phytoplankton bloom. Similarly, smaller peaks occurred in May and March. Copepods dominated the zooplankton forming up to 60% of total species composition. High zooplankton diversity occurred in June–July when zooplankton abundance was lowest as compared to February–March. Spatially, the highest diversity was recorded at station 1 located towards the open sea as compared to the other stations located farther inshore.