Saltmarsh and seagrass beds on the south-eastern coast of Bangladesh: vegetation characteristics and adjacent fisheries diversity

Abstract

Saltmarsh and seagrass communities are coastal macrophytes. These communities perform a number of important ecological functions, one of which is to support substantial fishery resources either as a nursery ground or a refuge from predators. The Bangladesh coast houses saltmarsh and seagrass resources but there has been sparse information on the diversity of fisheries adjacent to these plant communities. Consequently, this study was carried out to obtain information on the shoot density and biomass of the dominant saltmarsh (Porteresia coarctata) and seagrass (Halophila beccarii) species together with the diversity of fisheries adjacent to saltmarsh and seagrass beds on the south eastern coast of Bangladesh. The below-ground biomass of P. coarctata was found to be significantly higher than the above-ground biomass, presumably so as to survive under harsh environmental conditions, for example strong wave exposure. The standing crops and shoot density of the seagrass H. beccarii showed a similar pattern to that of the same seagrass species observed elsewhere. Overall, 5356 individuals of the faunal population comprising 38 species (21 families) of fish, 8 species (3 families) of shrimps and 2 species (2 families) of crabs were recorded. The similarity percentage analysis showed that Thryssa dussumieri (24.77% contribution) and Exopalaemon stylifer (9.52% contribution) were the most dominant species. Probably, these species utilize saltmarsh seagrass beds as nursery and feeding grounds more than other species.