Diversity of Macrobenthic invertebrates at three stations from the middle part of Shatt Al-Arab River

The present study aimed at the community of macrobenthic invertebrates in three stations of the Shatt Al-Arab River, including Al-Muftia, Sendibad, and Al-Mohammadiat, and samples were collected for a period of six months, from July 2018 to December 2018, during which some environmental factors were measured. The macrobenthic invertebrate samples collected in three monthly replicates for each station were isolated and identified, and the densities, relative abundance, and ecological indices such as diversity, richness, and evenness were calculated. The results showed that the ranges of environmental factors measured for the water of the study stations, in general, were as follows: air temperature (26-39 ℃), water temperature (20-32 ℃), pH (7.1-8.1), electrical conductivity (5.1-10.7 mS/cm), dissolved oxygen (6.6-9.8 mg/L), and calcium between (80.2-160.3 mg/L). During the study, 12 species of invertebrates were recorded, two of which belonged to the phylum Annelida, five to the phylum Arthropods, and five to the phylum Mollusca. The highest density of registered species was recorded (944 ind/m2) during December at the Mohammadiat station for the species Melanoides tuberculata of Mollusca, and the highest relative abundance of registered groups was for the Mollusca group and amounted to 95%.As for the diversity indices, the highest value of diversity was 1.42 in Mohammadiat station during September, the highest value of richness was 1.61 in Sendibad station during November, and the highest value of evenness was 0.82 in Mohammadiat station during October.