One of the main goals of benthic ecology has been to understand the mechanisms regulating relationships between physico-chemical parameter and organisms. The present study shows that the macrofaunal communities of three mangrove ecosystems exhibit distinct variations. It is a characterized by temporal and spatial changes in its population and distribution pattern seems to be fully governed by the physico-chemical and hydrobiological characteristics of the environment. Intertidal fauna at the study area have to cope with harsh environmental conditions marked by high salinity, increased evaporation, wide seasonal temperature fluctuations, and different degrees of tidal amplitudes. These unique physico-chemical factors exert a strong influence on faunal assemblages, which are withstanding the situation. Owing to the heterogeneous nature of estuarine water, the relatively stationary benthic animals on the bottom have to endure
a wide range of environmental changes when the circulation carries different kinds of water over the site or borrow. Mangroves also possess some positive advantages of benthic animals, compared to the open coast. Estuaries are relatively sheltered against wind waves and ocean swell; most estuaries are also rich in food provided by river input, input from mangroves, and high primary production.