Macroinvertebrate Fauna Of A Tropical Freshwater Stream In Nigeria

Macroinvertebrate fauna of Ogbei stream in Anambra state, Nigeria was studied from monthly samples taken from six stations or sites with a benthic scoop net and a serrated cylindrical sampler(SCS) for 12 months (May, 2002 – Apri 2003). A toal of 11420 macroinvertebrates were colected belonging to 4 classes, 13 orders, 28 families and50 species. The fauna was dominated numerically by Insecta (98.29 %), Arachnida (0.81%) and Oligochaeta (0.66%). Diptera was the most abundant taxon (42.62%), foowed by Odonata (36.89%), Coleopera (9.76 %) and Hemiptera (8.22 %). Station 3 had the highest percentage of abundance of the macrofauna (28.56 %) followed by station 2 (19.54 %). The highest faunal diversiy was recorded in station 6 The macroinvertebrate composition, distribution abundance and diversity were influenced by substrate composition, good water quality and availability of food. Keywords : Tropical freshwater stream, Macroinvertebrate composition, Abundance, Distribution, Diversity Animal Research International Vol. 3 (3) 2006 pp. 553-561