A total of 352 freshwater fishes, belonging to three species of the family Cyprinidae were collected from the Greater Zab river in north of Iraq during the period from November 2000 to the end of November 2001. The inspection of their gills revealed the infection of these fishes with three species of monogenetic trematodes belonging to the genus Dogielius. These species included D. mokhayeri from Aspius vorax with a percentage incidence of 37.5%; D. molnari from Cyprinion macrostomum (33.3%) and D. persicus from Barbus luteus (41.2%). The record of this genus and its three above-named species of the present study are considered as the first record on fishes of Iraq.

F0od  and  feeding habits  of  Hetropnezt.s!fes ]ossili/}:. (Bloch)  have been  investigated.  Monthly samples (twice a  m()nth}  were   taken during  the period  from  March  2000  to February  20.Ql , using small -

meshed cast net. A total of l9J  ftsh were used to examine the stomach

contents.

The analysis   of  stomach contents of H  fo.s-silis in  the- area  of study  revealed   that  fish  were  fed  on  the  bottom, mid ·surface  and surface  &

    Three monogenean species of the genus Gyrodactylus viz. G. cotti Roman, 1956 on gills of Planiliza abu, G. mikailovi Ergens & Ibragimov, 1976 on gills of Chondrostoma regium and G. prostae Ergens, 1963 on gills of Alburnus caeruleus were recorded from Tigris river at Al-Shawwaka region, Baghdad. The description and measurements of these parasites as well as their illustrations where given. All these parasites are recorded here for the first time in Iraq.  
 

Seasonal variations of the species composition and abundance of Cladocera were studied in two stations at the end of the Tigris River and one station at the confluence of the Tigris with Euphrates area, at the beginning of the Shatt Al-Arab River in Al-Qurnah North of Basrah Province, from October 2015 to August 2016. Samples of zooplankton were collected by plankton net 100-µm. mesh size. The population density of Cladocera ranged between 1 Ind /m³ during summer and 211 Ind./m³ during winter at station 1 (Al-Jewaber Bridge). A total of 16 species of Cladocera belonging to 12 genera were recorded in the study. The average density of Cladocera ranged from 23.2 ind./m³ at Station 2 (Hamayon Bridge) to 53.7 Ind./m³

      This study was conducted to evaluate the effects of Tharthar Arm on the composition and diversity of Rotifera in Tigris River. Six sampling sites were selected, two on Tharthar Arm and four along the Tigris River, one before the confluence as a control site and the others downstream of the confluence. Seventy-seven species of Rotifera were identified in Tigris, whereas, 60 in the arm. The results showed that low density of Rotifera in Tharthr Arm decreased the density in Tigris from 239812.4 upstream of the confluence to 223315.5 at immediate downstream of the confluence. It also declined the mean values of richness, evenness and Shannon diversity indices from 5.19, 0.69 and 2.14 bit/Ind., before the confluence to 3.97, 0.73 a

  Two species of monogenetic trematodes of the genus Dactylogyrus were recorded in the present paper for the first time in Iraq from two freshwater fishes from Diyala river, Diyala province. The first species,  D. bocageii Alvarez Pellitero, Vicente et Gonzalez Lanza, 1981 was recorded from gills of Aspius vorax, the second species, D. lenkorani Mikailov, 1967 was recorded from gills of Barbus sharpeyi. The descriptions and measurements of these parasites as well as their illustrations were given.

Cosmochthonius reticulatus Grandjean, 1947 (Acari: Oribatei: Cosmochthoniidae) and Rhysotritia ardua ardua C. L. Koch, 1841 ( Acari : Oribate : Euphthiracari¬dae), are two species of oribatids mites first recorded in Iraq from a woodland in the central part of Iraq. The two species are described and illustrated.

This study is considered to be the first on this sector of Tigris River after 2003, to evaluate the effect of Tharthar Arm on the composition and diversity of Copepoda in Tigris River. Six sampling sites were selected; two on the Tharthar Arm and four sites along the Tigris River, one before the confluence as a control site and the others downstream the confluence; thirty-five copepod taxa were recorded, 34 taxa in the Tigris River and 25 taxa in the Tharthar Arm.
The highest density of Copepoda was in site 2 at Tharthar Arm was 265584.2 Ind./m3 lead to an increasing in Copepoda density in Tigris River from 63878.2 Ind./m3 in site 1 before the confluence to 127198.3 Ind./m3 in site 4 immediately downstream the confluence. Also, the me

The primary objective of this study was to investigate the current status of water-quality conditions and assessment it in the Tigris River, Baghdad, Iraq, and to determine how those conditions are changing over time of pollution if any. A series of Hydrochemical tests were carried out to ascertain the influence of major Cations and Anions, Total Dissolved Solids (TDS), Electrical Conductivity (EC) and Potential of hydrogen (pH) on the quality of water. To assess the environmental pollution of the study area: 34 water samples were collected along Tigris River from north to south Baghdad City; 17 on January 2019 and 17 on April 2019. Result of the test were compared with the World Health Organization standards, and showed that all the