BIODIVERSITY STUDY OF ZOOPLANKTON IN SELECTED BAHR Al-NAJAF DEPRESSION, NAJAF GOVERNORATE, IRAQ

The current study aims to assess zooplankton diversity in Bahr Al-Najaf depression using diversityindex, specimens were collectedfrom five sites at Bahr Al-Najaf depression, Iraq during April 2017 toMarch 2018.Forty-eighttaxa of zooplankton were identifiedincluding 26 taxa to Copepoda,17 taxa belonged to Rotifers and 5 taxa to Cladocera: Copepoda was the most dominant group (54.2%); Rotifera comprised (35.4%); Cladocera comprised (10.4%). Relative abundance index of zooplankton showed Copepodite and nauplii of Harpacticoid,Hexarthra mira, Daphnia sp.,Harpacticoidsp., and Copepodite and nauplii of Cyclopswere more abundant. According to the constancy index, the Copepoditeandnauplii of Harpacticoid, nauplii Cyclops, nauplii stage andHexarthramiracan be considered as the most frequent; Shanon-Weiner diversity index values of zooplankton recorded less value 0.48 in August 2017 at site (5);while the higher value was recorded in April 2017at site (2) was 2.42; the higher value of species richness index was recorded in April 2017 at site (2) which was (7.2), the higher value of species uniformity index was recorded in February at site (2) and March at site (1) (0.61).The present study concluded that Copepoda was the most abundant of zooplankton with variations in zooplankton species (density and from month to another).