Effects of seasonal variation and tidal regimes on macrobenthic invertebrates of the Warri River, Nigeria

Abstract

An assessment of the effects of seasonal variation and tidal regimes on the distribution and density of macrobenthic invertebrates of the coastal Warri River, southern Nigeria was carried out from July 2014 to February 2015. Samples were collected from five longitudinal stations from headwater to mouth during high and low tidal regimes in the wet and dry seasons. A total of 50 taxa comprising 1664 individuals /m² were collected. Macrobenthic invertebrates were significantly more abundant (P < 0.001) during the low tide than during the high tide and during the dry than in the wet season (P<0.001). In general, seasonal variation and tidal regimes siginificantly influenced macrobenthic community structure of the Warri River. Results are therefore more authentic and holistic when sampling in coastal tidal rivers takes into account, tidal and seasonal variations. It is therefore recommended that sampling for environmental baseline data acquisition in tidal rivers should be carried out to cover high and low tidal regimes and also the dry and wet seasons.

Keywords: Macrobenthic invertebrates, tidal regimes, seasonal variation, taxa, density