Anthropogenic Influences on Physico-Chemical Quality, Fish and Macrophyte Diversities of River Adofi, Southern Nigeria.

Abstract

&lt;b&gt;Background and Objective:&lt;/b&gt; Freshwater systems support agriculture, industry and even human existence. Pollution due to human activities affect the quality of water bodies thereby threatening biodiversity. This study, therefore, investigated the anthropogenic influences on physico-chemical quality, fish and macrophyte diversities of River Adofi. &lt;b&gt;Materials and Methods:&lt;/b&gt; Three sampling stations along River Adofi at Ejeme-Aniogor (Station 1), Utagba-Uno (Station 2) and Umuleke-Ossissa (Station 3) were selected based on ecological features and the presence of human activities. Water samples were collected fortnightly for 6 months and water quality was determined. Fish and macrophyte species were collected and diversity indices were calculated. &lt;b&gt;Results:&lt;/b&gt; Physico-chemical parameters were significantly different (p<0.05) in all three stations except for magnesium, calcium and nitrate. Temperature, total dissolved solids, conductivity, COD, total alkalinity and magnesium were higher (p<0.05) in Station 2 at Utagba-Uno where a rubber factory effluent discharges into the river. Out of 15 families, 18 genera and 26 species of fish collected &lt;i&gt;Oreochromis &lt;/i&gt;species were more abundant, followed by &lt;i&gt;Gymnarchus niloticus&lt;/i&gt;. Mokochidae and Clariidae had higher diversities than other families. Macrophytes recorded were 53 taxa from 21 families and 33 genera with emergent and submerged life forms dominating. Poaceae dominated with nine species. Shannon index increased with increasing species richness and evenness with both fish and macrophytes evenly distributed. &lt;b&gt;Conclusion:&lt;/b&gt; Lower diversity of fish species observed in Station 2 may be due to influences of effluent discharges into the river while domestic and agricultural activities enhanced abundance and diversity of fish and macrophytes at Station 3.