A Study of Invertebrates Community in Lesser Zab River/ Kurdistan Region-Iraq

Abstract

A study of invertebrates community has been carried out at three sites selected on Lesser Zab River. Monthly samples of water, zooplanktonic and benthic invertebrates were collected for the period of May to October 2014. Some physical and chemical properties of water were studied and the results showed that the water temperature ranged from 15-31 °C, hydrogen ion concentration of studied sites were found to lie in the alkaline side, it was ranged between 8.1-8.9, turbidity ranged from 14-105 NTU, salinity from 0.19 to 0.29 ppt, dissolved oxygen from 4 to 5.4mg.l -¹ and electrical conductivity from 316 to 454µs.cm ­¹ . Concerning to the zooplankton, 29 species were identified which belonged to Copepod 76%, Cladocera 16% and Rotifera 8%. A total of 18 species of benthic invertebrate were identified dominated by Annelida 67%, followed by Nematodes 20%, Insects 8%, Mollusca 4.7%, Targigrada 0.2% and Decapoda 0.1%. According to Shanon-Weiner index, species diversity for zooplankton invertebrates was ranged from 0.067 to 0.90 bits/ind. While for benthic invertebrates was ranged from 0.025 to 1.31 bits/ind. Sorensen similarity index showed that the highest similarity was recorded between site (2) and site (3) with 87.17% and 69.56% for both of planktonic and benthic invertebrate communities respectively. Environmental Protection Agency standards revealed that Lesser Zab River was unpolluted in site1 and site2 and slightly polluted in site (3).