Long term observation of zooplankton biomass and community structure was carried out at a fixed station in the tropical coastal waters off Port Dickson in the Straits of Malacca, Malaysia, from June 2002 to July 2005. Hydrographic conditions showed significant statistical difference between the SW (late May-Sep) and NE (early Nov-mid Mar) monsoon seasons. Copepods dominated the zooplankton community and among them, Acartia, Acrocalanus, Paracalanus, Euterpina, Corycaeus and Oithona were dominant. They accounted for 90 % of the total copepod population throughout the study period, emphasizing the importance of small species in tropical zooplankton communities. Zooplankton biomass ranged from 752.5 to 2,788.3 inds. m-3, and generally peaked at the beginning of each monsoon and gradually decreased toward the intermonsoon period. Environmental classification using cluster analyses showed two distinct monsoon specific community groups. Size fractionation of the plankton revealed that different taxa within the zooplankton community displayed seasonal succession relative to the monsoon seasons. Temporal succession such as the appearance of Appendicularia during the NE monsoon being replaced by large populations of meroplankton during the SW monsoon in the macroplankton may be caused by monsoon related shift in size spectra of the autotrophic biomass. Species succession of the dominant copepods Acartia pacifica and A. spinicauda is suggested to be due to interspecific competition between two congeners of similar sizes. Annual pico-, nano-, micro-, meso-, and macroplankton carbon biomass were 130.9±43.5, 199.8±54.7, 70.7±31.9, 2.5±1.8 and 3.1±2.4 mg m-3, respectively. The nano- and picoplankton carbon biomass were significant at 49.5 % and 31.8 % of total biomass throughout the study period, respectively, defining tropical trophic structure characteristic to the Straits. The results convey a complex and diverse zooplankton community but despite overall variability, evidence of succession pattern is present, influenced by prevailing monsoon regimes and shifts in the size classes of the autotrophic community. Study on the feeding ecology of A. pacifica revealed the ability of the dominant copepod to effectively utilize food from opposite extremes of the size spectra, the pico- and microplankton. Increased ingestion rates and reduced filtering rates with increasing ambient food concentration effectively transfers energy to egg production, contributing to the successful survival of this species in low phytoplankton tropical waters. Species specific embryonic development times of three congeneric Acartiid copepods were D=294(T-4.47)^-2.05, D=894(T+1.94)^-2.05 and D=352(T-4.30)^-2.05 for Acartia erythreae, A. pacifica and A. spinicauda, respectively. The results reflected respective habitat distribution and adaptive significance of the population. A. pacifica, a species with population distribution extending to temperate regions, exhibited a lower biological zero compared with the primarily tropical species A. erythreae and A. spinicauda. Study of embryonic development times enables the empirical determination of population dynamics of plankton in tropical coastal waters.