TEMPORAL DISTRIBUTION OF SHELLFISH ASSEMBLAGE IN THE KARNAFULLY RIVER ESTUARY, BANGLADESH

Abstract

Bangladesh has a coastline of 480 km along the North and North-East part of the Bay of Bengal. It has an internal estuarine water area of 7,325 sq. nautical miles up to 10 fathom depth baseline, territorial waters of 2,640 sq. Karnafully River estuary is in the southeast of Chittagong district. This study has been covered temporal distribution of species composition, abundance and water quality parameters in the Karnafully river estuary, Chittagong, Bangladesh with Estuarine Set Bag Net. Shellfish species together with water sample were collected at each season (winter, premonsoon,

monsoon, post-monsoon and) in 2013 to analyze. All the multivariate analyses were performed using the software PRIMER V6, Canonical correspondence analysis (CCA) using the SPSS version17 and PAST software. The most dominant family was found to be The most dominant family was found to be Penaeidae (4 species) and Portunidae (4 species) followed by Palaemonidae (2 species), Potamidae (2 species), Acetes (2 species), Calappidae (1 species), Mytilidae (1 species), Squillidae (1 species). The most dominant taxa were found to be Exopalaemon styliferus (35.71%). The assemblages were dominated by marine and brackish water species. The diversity indices showed significant differences in temporal shellfish assemblage structure. Analysis of similarity (ANOSIM) result showed significant differences between seasons. At the similarity of 53%, three groups were attained while post-monsoon showed separate clustering from other groups. The CCA ordination indicates that temperature, pH and dissolve oxygen (DO) are the three most important environmental parameters shaping the species assemblage structure at Karnafully River estuary.