Author(s)

Benard Mwakisunga¹, John F. Machiwa², Harishchandra Bhagwanji Pratap¹

¹Department of Zoology and Wildlife Conservation Sciences, University of Dar es Salaam, Dar es Salaam, Tanzania.
²Department of Aquatic Sciences and Fisheries Technology, University of Dar es Salaam, Dar es Salaam, Tanzania.

Sediment and macrobenthic fauna distribution at Dar es Salaam harbour channel were investigated to attest the influence of sediment grain size distribution and total organic carbon contents on benthic macrofauna dominance and diversity. Sampling campaign was conducted from January to April, 2019 in 25 sampling stations along the channel. Sediment grain sizes ranged between 0.7405 and 0.00273 mm with an average of 0.0804 mm classified as medium silt. Sediment distribution showed an onshore-offshore pattern consisting of fine dark clay-silt sediments in the southern part of the harbour close to Mwalimu Nyerere Bridge, medium (sandy) at the harbour and coarse sandy offshore. Five classes of macrofauna were identified with sedentary Polychaetes (Diopatra cuprea) found in tubes and free forms being dominant in most of the sediment types, however more abundant in clay-silt. High species diversity index values were encountered in sediments with medium total organic carbon (TOC) and sediment grain sizes (sand-silt). Apparently, low species similarity indices were observed in all sediment type indicating significant dissimilarities in species composition among sediment grain sizes. Thus, the distribution of benthic macrofauna species along Dar es Salaam harbour channel is strongly influenced by the sediment grain sizes and organic carbon contents in sediments.

Sediment Grain Size Distribution, Benthic Macrofauna Diversity and Abundance, Total Organic Carbon Distribution, Dar es Salaam Harbor Channel

Mwakisunga, B. , Machiwa, J. and Pratap, H. (2020) Assessment of Sediment and Benthic Macrofauna Distribution at Dar es Salaam Harbour Channel. Journal of Geoscience and Environment Protection, 8, 133-147. doi: 10.4236/gep.2020.83010.