BioRisk >. 173-186 (2009) Via ie. fe aa ere doi: 10.3897/biorisk.3. | RESEARCH ARTICLE BioRisk www.pensoftonline.net/biorisk Biodiversity & Ecosystem Risk Assessment Structure and ecological indices of fish assemblages in the recently restored Al-Hammar Marsh, southern Iraq Najah A. Hussain', Abdul-Razak M. Mohamed’, Sajed S. Al Noo’, Falah M. Mutlak?, Ibrahim M. Abed?, Brian W. Coad?* | Department of Biology, College of Science, University of Basrah, Iraq 2. Department of Fisheries and Marine Resources, College of Agriculture, University of Basrah, Iraq 3 Marine Science Centre, University of Basrah, Iraq 4 Canadian Museum of Nature, Ottawa, Canada Corresponding author: Najah A. Hussain (dr_najah_h@yahoo.com) Academic editor: F Krupp | Received 10 March 2009 | Accepted 16 December 2009 | Published 28 December 2009 Citation: Hussain NA, Mohamed A-R M, Al Noor SS, Mutlak FM, Abed IM, Coad BW (2009) Structure and ecological indices of fish assemblages in the recently restored Al Hammar Marsh, southern Iraq. In: Krupp FE, Musselman LJ, Kotb MMA, Weidig I (Eds) Environment, Biodiversity and Conservation in the Middle East. Proceedings of the First Middle Eastern Biodiversity Congress, Aqaba, Jordan, 20-23 October 2008. BioRisk 3: 173-186. doi: 10.3897/biorisk.3.11 Abstract The aim of the present study is to determine the species composition, the structure of the fish assemblages, and to develop ecological indices in the restored east Al- Hammar Marsh. Fish were collected from October 2005 to September 2006 at two stations (Mansoury and Burkah). Fish samples contained freshwater species, both native and alien, and marine species. Thirty-one species were collected, eleven of them marine, the rest freshwater. Native species numbered 14 (45%), alien species 6 (19%) and marine species 11 (36%). Resident species formed 32.2%, seasonal species 16.0% and occasional species 51.6% of the fauna. The abundance of species varied, Liza abu being the most dominant species, with Carassius auratus ranking second and Acan- thobrama marmid ranking third, comprising 35.8%, 23.6% and 10.6% respectively. Ecological indices were as follows: diversity ranged from 1.07 in November to 2.01 in July, richness ranged from 0.74 in December to 2.83 in July, and evenness ranged from 0.48 in November to 0.84 in December. The highest monthly sim- ilarity was in May at 77% and lowest in December at 29%. Water temperature showed medium correlations (0.62 and 0.58) with both the number of species and the total catch, respectively, while salinity exhibited weak positive correlations (0.05 and 0.26) with both the number and the total catch of species, respectively. Temperature is related to species number, presumably as a surrogate for many other seasonal changes. Keywords Species composition, fish assemblage, ecological indices, tidal marsh diversity, Mesopotamian marshes, alien species, Iraq Copyright Najah A. Hussain et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 174 Najah A. Hussain et al. / BioRisk 3: 173-186 (2009) Introduction The marshes of southern Iraq were the largest wetlands in south-western Asia, covering more than 15,000 km? and representing about 44% of the inland freshwater bodies of Iraq. These marshes were a natural refuge for many aquatic organisms, especially fish and waterfowl. The environmental, hydrological and physiographical setting formed a unique ecosystem, allowing high biodiversity and richness of the aquatic biota. The marshes were also characterized by their productivity (Al-Hilli 1977, Al-Hilli et al. 2009, Al-Zubaidy 1985, Al-Mayah 1992) and consequently were the richest and rarest biotope in the region. The Mesopotamian marshes were considered by FAO (1999) as the major source of inland fisheries (60%) in Iraq, estimated at 23,600 tonnes (Partow 2001). They were the permanent habitat for millions of waterfowl and a flyway for millions more migrating between Siberia and Africa (Evans 2002). Al-Hammar Marsh is situated south of the Euphrates River and extends from Nasiriyah City in the west of Iraq to the outskirts of Basrah City on the Shatt al-Arab River in the east. To the south is the saline-brackish Main Outfall Drainage (MOD) channel, sabkhas and the sand dune belt of the southern desert. The marsh area com- prises 2800 km? of permanent marsh, expanding to over 4500 km’ during the period of spring flooding and temporary inundation (Iraq Foundation 2003). The formation of Al- Hammar Marsh was due to the deposition of the suspended load of the Tigris-Euphrates rivers and resulted in a shift from brackish lagoon and coastal marsh to inland marsh, occupied by fresh to brackish water (Aqrawi 1993, Aqrawi and Evans 1994). Al-Hammar Marsh is the largest southern marsh extending through two provinces (Basrah and Nasiriyah). It is approximately 120 km long and 25 km wide. Maximum water depth in the marsh ranges from 1.8 m to 3.0 m. The marsh narrows about its middle, and consequently can be divided roughly into two parts, west and east, con- nected by a shallow channel (Fig. 1). Planned drainage processes started in the early 1990s to divert the riverine water of the Tigris, Euphrates and Shatt al-Arab rivers away from the southern marshlands, resulting in a catastrophic loss of the native aquatic flora and fauna. In 2002, 93% of the permanent marshes defined in 1973 had been destroyed. Only 14.5% of the Al- Hammar Marsh remained (Richardson and Hussain 2006). Since 2003, great efforts have been made to restore the marshes and revive the wetlands environment. As of August 2007, the marshes had recovered almost 58% of their former area in 1972 ac- cording to UNEP/IMOS (2007). After reflooding in April 2003, the west part of Al-Hammar Marsh was fed pri- marily from tributaries of the Euphrates, but the eastern part received a considerable amount of water from the Shatt al-Arab River, and groundwater recharge was another source of replenishment. The eastern part of Al-Hammar is a tidal marsh affected by the semi-diurnal tide from the Arabian Gulf, with well oxygenated oligohaline water, grey mud-silt sediments with low total organic carbon (TOC), and an alkaline pH (Hussain and Taher 2007, Tahir et al. 2008). Structure and ecological indices of fish assemblages in the recently restored Al-Hammar Marsh... 175 : Hiuwaza = : Marsit ; : z Chybaesh Marsh [31°00 ” Hammar Marsh IRAQ a : = ae eee as “ = ’ ‘ ‘ ii 30°00 KUWAIT ARABIAN GULF 47°30 48°15 Figure |. Map of southern of Iraq, showing the location of Al-Hammar Marsh (I Mansoury Site, 2 Burkah Site). The structure of the fish assemblage in the southern marshes has not been studied. A few taxonomic works refer to the marshes in passing (Khalaf 1961, Mahdi 1962, Coad 1991) and recently reports on the environmental restoration of the southern marshes have appeared (e.g., IMRP 2006, ARDI 2006) along with articles concerned with the occurrence and biology of marine and diadromous fish (Mohamed et al. 2009). Most previous studies have focused on biological aspects of some of the fresh- water fishes in Al-Hammar Marsh (Barak and Mohamed 1983, Dawood 1986, Jasim 1988, Al-Sayab 1989, Al-Kanaani 1989). The aim of the present study is to determine the structure of the fish assemblage and the species composition in the restored Al-Hammar Marsh. Previously, no studies were conducted on the diversity of the fishes, taking into consideration their relative abundance, the monthly changes in ecological indices, and the similarity between sam- pled months coupled with the effects of environmental factors like water temperature and salinity. 176 Najah A. Hussain et al. / BioRisk 3: 173-186 (2009) Material and methods From October 2005 to September 2006, fishes were collected monthly from two selected sites, both in east Al- Hammar: (1) Mansoury (30°40°32”N 47°37'21”E), environmentally considered as a tidal channel marsh and desiccated freshwater sta- tion, and (2) Burkah (30°40’22”N 47°33°03”E), a tidal open water marsh and desic- cated station (Fig. 1). Sampling was carried out using a seine net (20 m long with a 2.5 cm mesh), fixed gill nets (50 m to 100 m long with 2.5 cm to 10 cm mesh size), and electro-fishing gear. Specimens were immediately transported to the laboratory on crushed ice. Water temperature and salinity were measured to determine the rela- tionships of these two factors with the number of species and total catch of species. Fishes were identified to species by using Khalaf (1961), Mahdi (1962), Beckman (1962) and Coad (1991). The ecological indices of the fish assemblage in east Al-Hammar Marsh, namely relative abundance, diversity, evenness, richness and similarity were calculated month- ly according to Odum (1970), Shanon and Weaver (1949), Pielou (1977), Margalef (1968) and Boesch (1977), respectively. Fish species were divided into three categories according to their temporal occurrence in the monthly samples following Tyler (1971). Results Effects of abiotic factors The monthly fluctuations in air and water temperatures and salinity in east Al-Ham- mar Marsh are illustrated in Fig. 2. Air temperature ranged from 15°C in February to 33°C in June and water temperature changed from 12.5°C in February to 29°C in July. The minimum value of salinity was 1.2 mg/l in August and the maximum value was 2.0 mg/l in May and July. The relationships of water temperature and salinity with the total catch of indi- viduals and the number of species in Al- Hammar Marsh are shown in Fig. 3. Water temperature showed a significant positive correlations with the number of species (r = 0.620, p < 0.05) and the total catch of fish individuals (r = 0.578, p < 0.05), while the salinity showed very weak positive correlations with both of them, r = 0.056 and r = 0.262, p < 0.05, respectively. Species composition and temporal occurrence The overall number of fish species caught from the marsh was 31, belonging to 14 families (Table 1). Cyprinidae, the dominant family in terms of number of species was represented by 12 species: Aspius vorax, Carassius auratus, Barbus luteus, B. sharp- eyi, B. xanthopterus, B. grypus, Cyprinus carpio, Ctenopharyngodon idella, Acanthobrama Structure and ecological indices of fish assemblages in the recently restored Al-Hammar Marsh... 177 - -e- - Salinity Hammar —_o— Air —©— Water Temperature (C) Salinity (mg/l) Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sep. Figure 2. Monthly fluctuations in air, water temperature and salinity in east Al-Hammar Marsh (2005-2006). marmid, Cyprinion macrostomum, Alburnus mossulensis, and Alburnus sp. Other spe- cies belonged to the families Mugilidae (Liza abu, L. subviridis and L. klunzingeri), Sparidae (Acanthopagrus latus and A. berda), Cyprinodontidae (Aphanius dispar and A. mento), Poeciliidae (Gambusia holbrooki and Poecilia latipinna), Gobiidae (Bathygobius fuscus and Boleophthalmus dussumieri), Clupeidae (Tenualosa ilisha), Siluridae (Silurus triostegus), Mastacembelidae (Mastacembelus mastacembelus), Heteropneustidae (Heter- opneustus fossilis), Engraulidae (Thryssa whiteheadi), Scatophagidae (Scatophagus argus), Hemiramphidae (Rhynchorhamphus georgii), and Soleidae (Brachirus orientalis). The fish fauna of eastern Al-Hammar Marsh may be broadly classified into three groups: native freshwater, alien and marine fish species. Fourteen native freshwater spe- cies (Aspius vorax, Barbus luteus, B. sharpeyi, B. xanthopterus, B. grypus, Acanthobrama marmid, Alburnus mossulensis, Alburnus sp., Cyprinion macrostomum, Liza abu, Aphanius dispar, A. mento, Silurus triostegus and Mastacembelus mastacembelus) constituted 45.1% of the total number of species. Six alien freshwater species (Cyprinus carpio, Heteropneus- tus fossilis, Gambusia holbrooki, Carassius auratus, Ctenopharyngodon idella and Poecilia latipinna) formed 19.4% of the total number of species. Eleven marine species (Tenu- alosa ilisha, Liza subviridis, L. klunzingeri, Acanthopagrus latus, A. berda, Boleophthalmus dussumieri, Thryssa whiteheadi, Scatophagus argus, Bathygobius fuscus, Rhynchorhamphus georgii and Brachirus orientalis) comprised 35.5% of the total number of species. The monthly variations of native, alien and marine species in Al. Hammar Marsh are illustrated in Fig. 4. The highest numbers of total, native and marine species were in July and the lowest in December. ‘There was a slight variation in the number of alien species throughout the year. Species occurring temporally in the Al-Hammar Marsh were classified into three groups. The resident species were ten. Four of them appeared in all 12 months (Liza abu, L. subviridis, Carassius auratus and Acanthobrama marmid), one in 11 months 178 Najah A. Hussain et al. / BioRisk 3: 173-186 (2009) (Barbus luteus), four in 10 months (Cyprinus carpio, Aspius vorax, Alburnus mossulensis and Heteropneustus fossilis) and one in nine months (Si/urus triostegus). The resident species, forming 32.3% of the total number, consisted of native, alien and marine species. Of the five seasonal species, Thryssa whiteheadi was captured in eight months and Tenualosa ilisha and Barbus sharpeyi in seven months, and the remaining two in six months (Bathygobius fuscus and Aphanius dispar). The seasonal species comprised 16.1% of the total number of species and the occasional species 51.6%. Sixteen species were categorized as occasional, two of them appeared in three months (Aphanius mento and Cyprinion macrostomum), two in two months (Barbus xanthopterus and Acantho- Salinity & Number 0.056 Salinity & Catch ass 0.262 Temperature & Number [GSS 0.620 Temperature & Catch Le 0.578 0 OZ 0.4 0.6 0.8 Correlation Coefficient Figure 3. The relationships of water temperature and salinity with the total catch of individuals and the number of species in Al- Hammar Marsh @ Total a Marine o Alien a Native 25 20 15 : | | | SI ile in 1K i | | Oct. Nov. Dec. — Jan. Feb. Mar. Apr May June July Aug. Sep. Figure 4. Monthly occurrence of total, native, alien and marine species in Al/ Hammar Marsh Structure and ecological indices of fish assemblages in the recently restored Al-Hammar Marsh... 179 pagrus latus) and twelve in one month (Barbus grypus, Mastacembelus mastacembelus, Boleophthalmus dussumieri, Scatophagus argus, Gambusia holbrooki, Ctenopharyngodon idella, Acanthopagrus berda, Rhynchorhamphus georgii, Poecilia latipinna, Brachirus ori- entalis, Liza klunzingeri and Alburnus sp.). The monthly variation of similarity of fish species composition in the marsh dur- ing the study period is shown in Fig. 5. The highest similarity level was found during May (77%) and the lowest during December (29%). Generally, the similarity level was high during the spring and summer months. Relative abundance and ecological indices A total of 16,199 fishes belonging to 31 species were collected from Al- Hammar Marsh, the highest number (2920) being in September and the lowest (800) in December. Liza abu was the most abundant species comprising 35.9% of the total number fol- lowed by Carassius auratus (23.6%), Acanthobrama marmid (10.8%) and Tenualosa ilisha (10.1%). The previous four species accounted for over 80% of the total catches. Liza abu was the dominant species throughout the year except October, with a peak in April. Carassius auratus was second in dominance (Table 1). Monthly variations in ecological indices of species are illustrated in Fig. 6. The diversity index fluctuated from 1.07 in November to 2.01 in July, with an overall value of 1.53. The richness index ranged from 0.74 in December to 2.83 in July, with an overall value of 1.76. The evenness index ranged from 0.48 in November to 0.84 in December, with an overall value of 0.60. Sep. 63 Hammar Aug. 6| July 67 June 6! May 77 Apr 65 Mar. 62 Feb. 53 Jan. 56 Dec. 29 Nov. 39 0 20 40 60 80 100 Jaccard Similarity Index Figure 5. Monthly variations of similarity of species in Al Hammar Marsh Najah A. 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