Sediment macro- and meiobenthic fauna distribution along the Kenyan continental shelf

Abstract

Endobenthic fauna diversity, density and relative abundance were studied along the Kenyan continental shelf at four stations (Shimoni, Kwale, Mombasa and Kilifi) sampled during the R/V Mtafiti’s maiden cruise between 12th and 21st December, 2015. A total of 16 macrobenthic taxa were recorded, with Amphipoda and Polychaeta dominating at all stations except Kilifi where no amphipods were recorded. Total densities of macrofauna ranged between 7 457 and 97 878 ind/m2. The highest macrobenthic dominance (0.37), and the lowest H diversity and evenness (1.49 and 0.29, respectively) were recorded in Shimoni, while the highest H diversity values (2.18 and 2.11, respectively) were recorded at Kwale and Mombasa, respectively, and the highest evenness (0.74) at Kilifi. A total of 24 meiobenthic taxa were recorded, dominated by nematodes and copepods at all stations. Densities of meiofauna ranged between 96 and 1705 ind/10cm2. The highest meiobenthic H diversities (1.67 and 1.63) were recorded at Shimoni and Mombasa, and the highest evenness (0.31) at Shimoni. The highest domi- nance (0.39), and lowest diversity (1.38) and evenness (0.21) were recorded at Kilifi. Sediment granulometry and total organic matter (TOM) displayed a north-south trend with the southern stations recording higher propor- tions of coarser sediments and low TOM, while the northern stations recorded higher proportions of finer sedi- ments and higher TOM.