Qualitative and quantitative distribution of mangrove associated macrobenthic fauna (molluscs and crabs) from waterfront to the back mangrove in Tumpat, Kelantan Delta

Abstract

The present study is to perfonn a survey on the qualitative and quantitative distribution of mangrove associated macrobenthic fauna (molluscs and crabs) from waterfront to the back mangroves in Tumpat, Kelantan Delta. The faunal sample were collected by hand picking and the sediment samples by hand shovel. Altogether, 19 species were encountered belonging to different group such as gastropods, bivalves, crabs and shrimp. On the whole, the assiminea brevicula is the most abundance species at Tumpat mangrove, Kelantan Delta with the percentage abundance of 37.18%. Species diversity indices was calculated base on ShannonWeiner, H' (loge), Eveness, J' and Margalefs richness index, d . The highest diversity of benthos is found at Transect 1 with H'=2.04 which exhibited J'=0.77, and d=2.8. Bray-Curtis Similarities were calculated based on species abundance (root transfonned) data from 36 stations and the resulting dendogram shows that 4 distinct benthic community groupings (at 38% similarity) could be distinguished. Mean percentage of TOC is ranging from 1.26±1.05% until 3.02±0.96% while mean percentage of silt and clay is ranging from 3.40±2.090/o until 11.21±4.83%. It has been observed that there is a weak significance between percentage abundance of macrobenthos and percentage of TOC in this study and there are no significance between percentage abundance of macrobenthos and percentage of silt and clay. Seasonally predictable changes in freshwater inflow, wind and tidal mixing, microalgal biomass and sediment erosion and deposition patterns all contributed to observed seasonal changes in abundance of macrobenthos in mangrove area. A few parameters such as salinity, temperature, dissolved oxygen and organic carbon should be studied to determine their relationship for the benthic community.