Journal of Ecosystem & Ecography
Open Access

Abstract

Community structure and distribution of mesozooplankton were studied in the coastal waters of Indian Sundarban mangrove wetland, formed at the estuarine phase of the river Hugli (Ganges) for better understanding of its ecological characteristics in terms of secondary production. Copepods, by their sheer abundance and diversity, formed the dominant group constituting ~ 57 ? 87 % of the total zooplankton followed by chaetognath, mysid, lucifer and hydromedusae. Correlation matrix among the 8 major copepod families revealed that two families namely Acartiidae and Pseudodiaptomidae maintain negative relationship with rest of the copepod families. As revealed from multiple regression analyses, three factors namely salinity, chlorophyll-a and transparency played significant roles in the distribution and survival of the copepod species. A typical aggregation of three monogeneric cyclopoid copepods (Oithona rigida, O. similis, and O. brevicornis) revealed a greater degree of dominance as well as endemicity in a mangrove-infested site. The epipelagic chaetognath Sagitta bedoti followed a similar trend of distribution with the total zooplankton where the juvenile (Stage I) exhibited higher percentage contribution. Cluster analysis confirmed a solitary group formed by Bestiolina similis for all the stations. IndVal index was estimated to recognize the indicator species for each station. Canonical correspondence analysis (CCA) was performed taken into account of the common dominant copepods with respect to hydrological parameters. Decadal changes in copepod community structure were also noticed which might be due to biological interactions and shifting of feeding behavior of copepods. The work deserves special attention in the occurrence of algal bloom as well as tropical cyclonic storms which bring pronounced changes in the community structure of mesozooplankton along with water quality characteristics.

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