Int. J. Aquat. Biol. (2022) 10(5): 429-437 ISSN: 2322-5270; P-ISSN: 2383-0956 Journal homepage: www.ij-aquaticbiology.com © 2022 Iranian Society of Ichthyology Original Article Fish diversity of the Euphrates River between Medina and Qurna cities, southern Iraq Sajad A. Abdullah1, Abdul Hussein J. Abdullah2, Yasser W. Ouda3 1Department of Biology, College of Education-Qurna, University of Basrah, Iraq. 2Department of Marine Vertebrate, Marine Science Center, University of Basrah, Iraq. 3Department of Biology, College of Education-Qurna, University of Basrah, Iraq. s Article history: Received 5 June 2022 Accepted 15 August 2022 Available online 2 5 October 2022 Keywords: Ecology Biodiversity Euphrates Inland waters Abstract: The present study was conducted to evaluate the fish community and diversity status in the Euphrates River between Medina and Qurna cities, northwest of Basrah Province, Iraq. In addition, the relationship between some environmental parameters, including water temperature, dissolved oxygen, salinity, pH, and turbidity, and fish abundance were investigated by sampling from November 2020 to October 2021. Based on the results, there were no significant differences (P>0.05) in the environmental factors between the two studied sites except for salinity and turbidity. During the study, a total of 7387 fishes were collected belonging to 12 families, 21 genera, and 22 species. The Cyprinidae was dominated by seven species, followed by the Luciscidac with three species, the Cichlidae and Mugilidae families with two each, and the rest with one species each. There were ten natives, eight exotics, and four marine fish species. Planiliza abuc was dominat species with 26.11 % of the total catch. Significant differences (P<0.05) were found in species richness and number of the collected individuals between two sites. Based on the results, fish species can be classified into three groups based on their distribution; common species with nine species, accounting for 98,66%; seasonal species with four species accounting for 0.798% and rare species, with nine species accounting 0.541% of total richness. Three species of P. abu, Coptodon zillii and Carassius auratus were dominant species with 63.110% of the total catch. Introduction A study of fish communities gives a clear picture of their stocks (Dwivedi et al., 2016) that are used in managing aquatic systems (Simonovic et al., 2017; Pyron et al., 2019). The fish community is affected by environmental factors that can be observed using diversity indices (Abdullah et al., 2019b; Al-Helli et al., 2019; Zarei and Krakhmalnyi, 2019) such as richness, diversity, and evenness (Abbas et al., 2017). Several studies have been performed in the inland waters of Iraq to investigate the environmental and biological effects the fish composition e.g. in the Euphrates River, Al-Noor et al. (2009) analyzed fish population structure and recorded 21 species, Hussein et al. (2015) worked the fish structure in the Euphrates River between Chibyaish and Mudyna and recorded 24 species belonging to seven families, and 12 species, Khaddara (2014) studied the physiochemical of fish Correspondence: Sajad A. Abdullah DOI: https://doi.org/10.22034/ijab.v10i5.1762 E-mail: sajad.aballah@uobasrah.edu.iq DOR: 20.1001.1.23830956.2022.10.5.10.1 structure in the Euphrates River, Abdullah (2017) documented the fishes of the Tigris River at Al- Qurna city and Abood (2018) reported the structure of fish assemblages in the Shatt Al-Arab River. In this regard, the current study aimed to assess the fish structure of the Euphrates River's Medina and Qurna cities, Southern Iraq using diversity indices by providing their relationships by some environmental parameters. Material and methods The Euphrates River has a length of 2775 km as the 27th longest river in the world (Vander, 1975). It feeds large agricultural land in the northern Basrah Province of Iraq. For this study, two sampling sites were selected between the cities of Medina and Qurna, including (1) the northwest site in the Al- Medina bridge (718852N, 3425256E) and (2) Al- Qurna city at Pipe bridge (729605N, 3431444E). https://ij-aquaticbiology.com/index.php/ijab/article/view/1762 430 Sajad et al./ Fish diversity of the Euphrates River between Medina and Qurna cities Water samples were collected from the study area monthly from the middle of the river at a depth of 20 cm. Water physiochemical parameters were measured during fish sampling between November 2020 and October 2021. Water temperature (°C) was measured using a thermometer, Dissolved oxygen (DO) using a YSI55 device, salinity as PSU using Extech 31156 device, pH using Lovibond-Senso Direct 150 device, turbidity as Nephelometric turbidity unit (NTU) by HANNA HI93703 device. Several fishing methods, such as bottom net (160 m in length with 6.4 mm mesh size), gill nets (1x60 m2 with 15 mm mesh size), cast net (with a diameter of 4 m with 1.5 mesh size) and a hand net for small fishes were used to collect fishes. In addition, some data are based on the catches of local fishermen. The fish were identified based on Carpenter (1997), Coad (2015), and Eagderi et al. (2019, 2022). The relative abundance of fish species was calculated according to Odum (1979). Biodiversity indices, including diversity (Shanon, 1949), evenness (J) (Pielou, 1977) and richness index (D) (Margalef, 1968) were also calculated. Fish were also divided based on their occurrence in the monthly samples (Tyler, 1971), and dominance (D3) (Kwak and Peterson, 2007). SPSS (ver. 19) was used for statistical analysis by applying ANOVA to assess differences in ecological indices, the number of species and individuals (P≤0.05) between the two sites and Principal Component Analysis (PCA) to analyze the relationship between physicochemical characteristics and the study period's months. Results Water temperatures, salinity and DO during the study period are presented in Figure 1. Water temperatures were between 11°C in January and 36.5°C in July, with a mean of 21.3±8.5°C. DO was recorded between 7.4 mg/l in July and 8.9 mg/l in January, with a mean of 8.07±0.43 mg/l. Salinity levels ranged from 1 g/l in February to 2.6 g/l in July, with a mean of 1.7±0.5 g/l. Ph was within the alkaline range ranging from 6.9 in July to 8.5 in March, with a mean of 7.85±0.4 (Fig. 2). The turbidity ranged from 7.8 NTU in August to 23.6 NTU in December, with a mean of 7.85±0.49. There were no significant differences between the environmental parameters of the two sites (P>0.05) except salinity and turbidity. In the PCA, the first two PCs accounted 82.79 and 11.11% of the variances, respectively (in total 93.90%). The PC1 mostly includes factors of temperature and salinity. There was a correlation between July and September. Some parameters, such as DO and pH were correlated with January, February, March, April, and November. Based on the results, there is a positive correlation between turbidity and December and May (Fig. 3.) Figure 4 shows the correlations between the abundance and fish richness and water temperature, dissolved oxygen, salinity, pH, and turbidity. The water temperature positively correlated with the Figure 1. Monthly variations in water temperature, dissolved oxygen and salinity in the study area of the Euphrates River during 2020-2021. 431 Int. J. Aquat. Biol. (2022) 10(5): 429-437 richness and species abundance (r = 0.430, r = 0.07, respectively). The richness and fish’s abundances had weak positive correlation (r = 0.45, r = 0.08, respectively) with salinity and negative correlation (r = -0.31, r = -0.01, respectively) with DO and turbidity (r = -0.69, r = -0.12, respectively). PH showed a negative correlation (r = -0.38) with richness and a positive correlation (r = 0.25) with the fish’s abundances. A total of 7387 fish individuals were collected during the study period belonging to 12 families, 21 genera, and 22 species, of which 10 were native, eight exotic fish species, and four marines. The Cyprinidae was dominated group by seven species, followed by the Luciscidac with three, the Cichlidae and Mugilidae with two species each, and the rest with one species each (Table 1). The monthly variation in the abundance and richness in the two study sites are shown in Table 2. At the northwestern sites, the total number of individuals was 3515, ranging from 154 in June to 423 in March, including 17 species ranging from 8 in February to 13 in May. The total number of individuals in southeast sites was 3872, ranging from 223 in January to 426 in May. There were 19 collected species in this site, ranging from ni9ne in May to 15 in August. The results showed significant differences (P<0.05) in species and individuals between the two studied sites. The relative abundance of fish species ranges from 376 in June to 724 in May, with 22 species and 21 genera. The species ranged from ten in December 2020 to 15 in July, with the lowest numerical abundance as 5.1% in June and 9.8% in May. Panaliza abu was dominated species, with 1929 specimens and 26.11% of the catch, ranging from 9.9% in June to 29.8% in February. Coptodon zilli had the second position with 1807 individuals and 24.46 %, ranging from 8.5% in June to 24.9% in July. The collected C. auratus was 926, accounting for 12.54% of the total catch, fluctuating from 5.9% in November to 18.4% in December. Alburnus sellal constitutes 12.33% of the total composition ranging from 3.5% in July to 14.7% in November, with 911 specimens. Oreochromis auratus had 11.09% of the total catch, then Carasobarbus luteus with 9.46%, Cyprinus carpio with 1.11%, and Siluris triostegus with 0.80%. The rest species ranged from 0.76%, representing A. marmiad species, to C. idella and G. rufa, which accounted for 0.01% of the total catch (Table 3). The monthly variation in the number of species is depicted in Figure 5. The number of native species fluctuated from four in November to eight in January 2021. The alien species number differs between Figure 2. Monthly variations in hydrogen ion and turbidity in two sites of the Euphrates River during 2020-2021. Nove. 2020 Dece. Janu. 2021 Febr. March April May June July Augu. Septe. Octo. Temp. Salin. DO Turb. pH -2 -1 0 1 2 3 4 5 6 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 F 2 ( 1 1 .1 1 % ) F1 (82.79 %) Biplot (axes F1 and F2: 93.90 %) Figure 3. Principal Component Analysis between physicochemical factors and months in the Euphrates River during 2020-2021. 432 Sajad et al./ Fish diversity of the Euphrates River between Medina and Qurna cities three in December and seven in July. The abundance of marine species at the second station was notable, with one species recorded in December, January, March, May, July, and October and four in November. The results of biodiversity indices, including diversity (H), evenness (J) and richness (D), are presented in Figure 6. The lowest rate was recorded as 1.432 in December and the highest as 3.204 in July. The range of the evenness index was 0.365 in November to 0.754 in September. The values of the richness index were between 1.48 in August and 3.57 in October. The fish assemblage in the study area was divided into three groups (Fig. 7). The common species comprised nine, accounting for 98.695% of the total catch, including P. abu, C. zillii, C. auratus, A. sellal, O. aureus, C. luteus, C. carpio, S. triostegusa and A. marmid. Relative abundance% Family Habitat Species No 23.40 Cyprinidae F F F F F F F Carassius auratus + 1 Carasobarbus luteus* Garra rufa * 2 3 Ctenopharyngodon idella+ Cyprinus carpio + Hemiculter leucisculus + 4 5 6 Mesopotamichthys sharpeyi* 7 35.55 Cichlidae F Coptodon zillii + 8 Oreochromis aureus+ 9 26.22 Mugilidae F M Planiliza abu* 10 Planiliza subviridis 11 13.60 Leuciscidae F F F Acanthobrama marmid* Alburnus sellal * 12 13 Leuciscus vorax* 14 0.798 Siluridae F Silurus triostegus* 15 0.09 Clupeidae M Tenualosa ilisha* 16 0.08 Poeciliidae F Gambusia holbrooki + 17 0.07 Mastacembelidae F Mastacembelus mastacembelus* 18 0.05 Heteropneustidae F Heteropneustes foosilis + 19 0.05 Sparidae M Acanthopagrus arabicus 20 0.04 Engraulidae M Thryssa whiteheadi 21 0.03 Cyprinodontidae F Aphanius dispar* 22 * = Native species, + = Alien species, F=Fresh water species, and M= Marine water species. Table 2. Monthly variations in the number and richness of fish species in the Euphrates River from November 2020 to October 2021. Richness Number of individuals Months Site 1 Site 2 Site 1 Site 2 November 2020 10 14 321 393 December 9 12 221 279 January 2021 12 10 275 223 February 8 13 298 358 March 11 14 423 272 April 10 12 350 332 May 13 9 298 426 June 10 13 154 231 July 12 14 265 323 August 11 15 297 371 September 11 12 271 401 October 9 13 342 263 Total 3515 3872 Table 1. Fish species were collected from November 2020 to October 2021. 4 3 3 In t. J . A q u at . B io l. ( 2 0 2 2 ) 1 0 (5 ): 4 2 9 -4 3 7 T ab le 3 . M o n th ly v ar ia ti o n s in t h e re la ti v e ab u n d an ce o f sp ec ie s in t h e E u p h ra te s R iv er f ro m N o v em b er 2 0 2 0 t o O ct o b er 2 0 2 1 ( E u p h ra te s R iv er ). O c t. S e p . A u g . Ju ly Ju n e M a y A p r. M a r. F e b . Ja n . 2 0 2 1 D e c . 2 0 2 0 N o v . 2 0 2 0 T . N u m % N u m . % N u m . % N u m . % N u m . % N u m . % N u m . % N u m . % N u m . % N u m . % N u m . % N u m . % N u m . 1 9 2 9 2 5 .1 1 7 5 1 9 .5 1 7 8 1 8 .9 1 5 6 2 6 .7 1 7 8 9 .9 5 5 1 8 .2 1 7 5 1 1 .4 1 2 6 2 8 .1 2 5 9 2 9 .8 2 2 0 1 7 .8 1 0 2 1 9 .7 1 2 0 2 2 .4 1 9 0 P e n a li za a b u 1 8 0 7 2 0 .6 1 4 4 1 8 .5 1 6 7 1 9 .5 1 6 1 2 4 .9 1 6 6 8 .5 4 7 1 7 .2 1 6 5 2 0 .0 2 2 1 2 1 .9 1 9 9 2 2 .4 1 6 5 2 0 .9 1 2 0 1 2 .3 7 5 2 0 .8 1 7 7 C o p to d o n z il i 9 2 6 1 4 .0 9 8 8 .6 7 8 1 2 .7 1 0 5 1 2 .0 8 0 1 3 .7 7 6 8 .2 7 9 5 .0 5 5 6 .. 6 6 0 8 .9 6 6 1 1 .7 6 7 1 8 .4 1 1 2 5 .9 5 0 C a ra ss iu s a u ra tu s 9 1 1 9 .6 6 7 9 .4 8 5 8 .8 7 3 3 .5 2 3 9 .7 5 4 7 .9 7 6 1 0 .4 1 1 5 8 .6 7 8 1 0 .2 7 6 1 3 .1 7 5 1 0 .7 6 5 4 .7 1 2 5 A lb u rn u s se ll a l 8 1 9 8 .0 5 6 5 .5 5 0 1 2 .2 1 0 1 8 .9 5 9 1 2 .1 6 7 8 .8 8 5 7 .1 7 9 6 .2 5 6 8 .9 6 5 3 .8 2 5 5 .7 3 5 1 6 .8 1 4 3 O re o c h ro m is a u re u s 6 9 9 6 .2 4 3 6 .8 6 1 5 .0 4 1 8 .1 5 4 1 0 .8 6 0 8 .9 8 6 5 .2 5 7 3 .8 3 5 6 .9 5 1 1 8 .3 1 2 0 1 4 .3 8 7 2 .2 1 9 C a ra so b a rb u s lu te u s 8 2 0 .3 2 3 .9 3 5 1 .2 1 0 1 .2 8 1 .3 7 0 .6 6 0 .6 7 0 .1 1 0 .5 3 0 .4 3 C y p ri n u s c a rp io 5 9 0 .3 2 0 .2 2 1 .0 8 0 .9 6 2 .8 2 7 0 .5 6 0 .5 5 0 .2 1 0 .2 2 S il u ru s tr io st e g u s 5 6 0 .3 2 1 .1 1 0 1 .1 9 0 .9 5 0 .7 7 0 .5 6 1 .1 8 1 .0 6 0 .5 3 A c a n th o b ra m a m a rm id 3 8 1 .7 1 2 0 .4 4 0 .6 4 1 .2 1 2 0 .3 3 0 .3 2 0 .2 1 L e u c is c u s v o ra x 1 6 0 .8 5 0 .4 4 0 .4 4 0 .2 2 0 .2 1 H e m ic u lt e r le u c is c u lu s 8 0 .1 1 0 .1 1 0 .1 1 0 .2 1 0 .1 1 0 .1 1 0 .2 1 0 .1 1 P e n a li za s u b v ir id is 7 0 .1 1 0 .1 1 0 .2 1 0 .2 1 0 .1 1 0 .1 1 0 .1 1 T e n u a lo sa i li sh a 6 0 .1 1 0 .1 1 0 .2 1 0 .2 1 0 .1 1 0 .1 1 G a m b u si a h o lb ro o k i 5 0 .2 1 0 .2 1 0 .1 1 0 .1 1 0 .2 1 M a st a c e m b e lu s m a st a c e m b e lu s 4 0 .1 1 0 .1 1 0 .1 1 0 .1 1 A c a n th o p a g ru s a ra b ic u s 4 0 .1 1 0 .2 1 0 .1 1 0 .1 1 H e te ro p n e u st e s fo ss il is 4 0 .1 1 0 .1 1 0 .2 1 0 .2 1 M e so p o ta m ic h th y s sh a rp e y i 3 0 .1 1 0 .2 1 0 .1 1 T h ry ss a w h it e h e a d i 2 0 .2 1 0 .1 1 A p h a n iu s d is p a r 1 0 .1 1 C te n o p h a ry n g o d o n id e ll a 1 0 .2 1 G a rr a r u fa 6 0 5 6 7 2 6 6 8 5 8 8 3 7 6 7 2 4 6 8 2 6 9 5 6 5 6 5 0 7 5 0 0 7 1 4 N u m b e r o f In d iv id u a ls 8 .2 9 .1 9 .0 8 .0 5 .1 9 .8 9 .2 9 .4 8 .9 6 .9 6 .8 9 .7 R e la ti v e a b u n d a n c e 1 4 1 4 1 3 1 5 1 3 1 3 1 4 1 3 1 2 1 4 1 0 1 3 N u m b e r o f S p e c ie s 434 Sajad et al./ Fish diversity of the Euphrates River between Medina and Qurna cities Seasonal species included four species accounting 0.798% of the total catch: L. vorax, P. Subviridis, T. ilisha, and G. holbrooki. The occasional species consist of night species and by 0.541% formed H.leucisculus, M. mastacembelus, A. arabicus, H. foosilis, M. sharpeyi, T. whiteheadi, A. dispa, C. idella and G. rufa. Three species of P. abu, C. zillii and C. auratus were 63.1% of the total catch and P. abu with 26.11 % had the highest dominance index (D3) (Fig. 8) -1 -0.5 0 0.5 1 Water temp. DO Salinity pH turbidity No. of species No.of individuals Figure 4. Some ecological factors that influenced the richness and individuals of fishes in the Euphrates River during 2020-2021. Figure 5. Monthly variation in the number of exotic, marine, and native species in study sites during November 2020 to October 2021 in the Euphrates River. Figure 6. Monthly variations in the values of biodiversity indices in the study area in the Euphrates River during 2020-2021. 435 Int. J. Aquat. Biol. (2022) 10(5): 429-437 Discussion Ecological factors directly impact fish distribution in aquatic ecosystems (Roa-Fuentes and Casatti 2017). Based on the results, DO was negatively correlated with water temperature and salinity, but DO and PH had little fluctuation despite the temperature. Salinity is changed based on various factors, including evapotranspiration, agriculture fertilization, soil erosion, runoff water and other anthropogenic activities, and its value was within the permissible limits for the collected fishes (Al-Helli et al., 2019). Turbidity can be caused by a variety of factors, including dissolved organic compounds, bacteria, microscopic algae, suspended clay particles and colloidal solids, and it was in two sites were to be above 5 NTU, indicating a higher rate (WHO, 2010). The fish fauna of the studied area was 22 species belonging to 21 genera and 12 families, including 10 natives, 8 exotics, and 4 marines; the family of Cyprinidae was dominated taxa. Lazem and Atte (2016) in their work to assess the fish structure in the Euphrates River at Al-Samawa city, recorded 24 fish species that some of them not found in our work, including A. grypus, C. sublimus, C. kais, and L. xanthopterus. Mohamed and Abood (2017) on the assemblage of Shatt Al-Arab structure in the supremacy of Cyprinidae and the difference of species number caught and ecological factors during his study. The rest of the families, such as the Luciscidac family, have three species each, the Cichlidae and Mugilidae families have two species, while the remainder of the families has only one species; this study coincided with many researchers in recording several families in Iraqi inland waters such as Hossain et al. (2012), Coad (2015). At both sites, P. abu, C. zillii, C. auratus and A. sellal were the most abundant species forming 69.3% of the total catch. The rest of the species had little abundance (30.7%) of the total number of individuals in the study area. The native fish species constituted 50.142% of the total catch, but eight exotic species consist 49.56% of the total catch. Al- Amari et al. (2012) reported some of these fishes in the Euphrates River near Al-Hinia town, showing a high occurrence of exotic fishes that can threaten the native fishes as they grow faster by declining the water quality of the Euphrates River. The second site had four marine species, accounting for 0.297% of the total catch. Abdullah et al. (2021) reported increasing marine species in the lower Euphrates River. The biodiversity indices are used as a single number to describe the diversity of a system (Magurran, 1988). The biodiversity index values (H) in this study range from poor to medium, according to Shannon-Weaver index values, revealing differences between sites due to the appearance of marine species (Younis et al., 2010) in the second site. The result of the evenness index (J) indicates Figure 7. Fish species occurrence in fishing samples from the two study sites from November 2020 to October 2021 in the Euphrates River. Figure 8. Dominated three fish species in the study area from November 2020 to October 2021 in the Euphrates River. 436 Sajad et al./ Fish diversity of the Euphrates River between Medina and Qurna cities that two sites are within the half balanced to the unbalanced range, with a minor increase in the second site, due to the presence of some marine species in the lower of the Euphrates River (Mohamed et al., 2015). The richness (D) of the fish structure in the Euphrates River, according to Jorgensen et al. (2005), varied between disturbed and semi-complete, as found in the current work. According to Tyler (1971), the fish assemblage in the studied area was divided into three groups; common, seasonal, and occasional fish species. Panaliza abu, C. zillii, C. auratus, A. sellal, O. aureus, and C. luteus were common species, i.e they are collected during the 12 months sampling period. Mohamed and Al-Jubouri (2017) have also reported the presence of these species in a study of the fish community in the Al-Diwaniya River. Other species found in the monthly fishing samples were C. carpio, S. triostegusa, and A. marmid in this river (Al-Zaidy et al., 2019). Four seasonal fish species (L. vorax, P. Subviridis, T. ilisha, and G. holbrooki) were recorded i.e. their presence varied monthly. The rest of the fishes were rare species. The three most abundant fish species of P. abu, C. zillii and C. auratus were dominant (D3) in the Euphrates River as reported by other researchers in Iraqi inland waters (Salman, 2012; Jawad et al., 2021). Acknowledgment The authors thank O. 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