Ecological Structure of Macrobenthic Invertebrates of the Benin River, Southern Nigeria, Before the Seaport Development Project

Macrobenthic invertebrates are major components of aquatic ecosystems. Because of their partial or sessile motion, they can be used to assess water quality status. The Benin River is a beehive of human activity, and with the development of the proposed seaport along its course, its physical, chemical, and biological components may be affected. The need to document macrobenthic invertebrates before the seaport development prompted this study. Four stations were selected between Ajoki and a section opposite Young Town, employing both kick sampling and Ekman grab techniques. Seasonal influence on the distribution and abundance of macrobenthic invertebrates was observed. In total, 3,267 macrobenthic invertebrates were collected during the sampling period. The highest number of taxa (35) were recorded in Station 1, and the highest number of individuals (1,103) was in Station 3. The dominant macrobenthic invertebrate group was Decapoda (76.61%); Diptera (6.15%) and Ephemeroptera (4.62%), others constituted the remaining 12.62%. There was a positive correlation between the family Diaptomidae and the physicochemical parameters, except for heavy metals.