The current study aimed to determine the morphometric and meristic characteristics of the North African catfish Clarias gariepinus (Burchell, 1822). Six specimens of C. gariepinus were collected from the Tigris River, in central Iraq. This study is considered the confirmation first record of this species in Iraq, and the second documentation of this exotic fish. The present species is characterized by a very long dorsal fin, a rounded caudal fin and four pairs of barbels.

In this research, Artificial Neural Networks (ANNs) technique was applied in an attempt to predict the water levels and some of the water quality parameters at Tigris River in Wasit Government for five different sites. These predictions are useful in the planning, management, evaluation of the water resources in the area. Spatial data along a river system or area at different locations in a catchment area usually have missing measurements, hence an accurate prediction. model to fill these missing values is essential.
The selected sites for water quality data prediction were Sewera, Numania , Kut u/s, Kut d/s, Garaf observation sites. In these five sites models were built for prediction of the water level and water quality parameters.

Water drainage pattern in the rivers and changed the nature of the renewed feeding areas
in the basin in terms of topographic and geological conditions and climate in addition to the
human role in organizing the process flow within these basins. This study addressed the
development of the Tigris River Hydrological in the city of Baghdad and found that the
annual rate of water drainage in the Tigris River was driven down very significantly,
especially in the past twenty years, and since 1996 up to 2014 record flow rates of less than
the overall rate of discharge of water, a (950 m3 / s ), in addition to the quarterly decrease the
discharge rates, especially since the beginning of the year 2000 and took converge all fo

In this study, a total of 209 individuals of leeches were collected from Al-Hindyia River / Babil Province. 116 individuals were identified as Erpobdella octaculata (Linnaeus, 1758), 50 individuals as Erpobdella punctata (Leidy,1870) and  43 individuals as Hemiclepsis marginata (Müller, 1774).  Four samples were collected monthly during a period from February to June 2018. Some physical and chemical water properties were also examined, including air and water temperature, potential of hydrogen pH, Electrical Conductivity EC, Total Dissolved Solid TDS, Dissolved Oxygen DO, and the Biological Oxygen Demand BOD₅.  Air and water temperature were r

Some biological aspects of the zebra mussel, Dreissena polymorpha have been studied at Al-Musayab thermal power plant ,sixty km. south west of Baghdad. Data collected during the period extended from November, 2002 to October, 2003 except for the month of April The population consisted of five age groups; O, I, II, III, and IV which have 0, 1, 2, 3 and 4 annuli respectively. The study also proved the validity of annuli readings for age and growth determination. The average annual growth rates for age groups O,I, II, III, and IV were 5.7, 5.5, 5.4, 5.2 and 5.4 respectively. Average calculated length for laboratory reared mussel was 2.5 mm compared to 5.4 mm in natural environment. Correlation coefficients were very high between age an

339 individuals , were sorted from 22 samples collected from three sites in Tigris River including , Al- Sarafiya district (S1), Al- Jaderiyah district (S2) and Al-Za'afaraniya district (S3), in addition to one site in the irrigation canal of the Al- Jaderiyah campus of the University of Baghdad (S4) , and in Al- Jeish canal(S5) east Baghdad. The sorting results revealed that the highest number of individuals of 102 was recorded at S4, whereas the lowest number of 24 individuals was recorded at S2. Regarding the sites, site S4 was the richest site with 30% of the total number represented 16 species, while each of S3 and S5 had 8 species only with 17.11% and 28.60% of the total individuals number respectively. The values of Jaccared Sim

    In the present study, a total of 272 freshwater fishes belonging to three species namely: Cyprinus carpio, Barbus xanthopterus and Aspius vorax, were collected from Euphrates river at Al-Haklania distrct, Al-Anbar province  during the period from August 2008 till the end of July 2009, by using gill nets and cast nets.       Fishes were survyed for intestinal parasitic worms. The investigation revealed the infectation of these fishes with four parasitic species: the digenetic trematode  Aspidogaster limacoides from the intestine of C. carpio, B. xanthopterus and A. vorax, larval nematode Contracaecum spp. from the body cavity of C. carpio and the external surface of intestine of B

   This study describes the determination of some phenols in four different zones of Tigris river in Iraq including, AL-Krieat, AL-Kadhimiya, AL-Jadiriyah, and AL-Adhamiyah. The  phenolic compounds analyzed were (2,3-dimethylphenol, 4-chlorophenol, 3-nitrophenol and 2,4-dinitrophenol) using reverse phase high performance liquid chromatography (RPHPLC) with a UV detector on ODS-C18 column(150×4.6 mm I.D) and a mobile phase consisted of methanol-water(30:70)%(v/v) at pH 5.0, and a column temperature at 30C° with 20 µL injection. UV detection helps to identify different phenols at wave length at 280 nm  with a flow rate at 0.5 ml/min. The separation time was (< 6) min.The results indicated that the AL-Adhami