Identification and density determination of jelly zooplanktons in Khuzestan coastal waters

Recently, we have been encountered to increasing jellyfish biomass in the world tropical coastal waters and due to their role in ecosystem food web, can be made direct and indirect effects on marine stocks and causing problems for fisherman’s communities. Now, the number of studies on this animal groups and factors which caused to jellyfish bloom has been increased. Present study was carried out for identification and density estimation of jellyfishes in the East and West coasts of Khure-Musa canal in Khuzestan coastal waters in North-West of Persian Gulf. Monthly samples were collected by two sampling methods from randomly sites in studied area in day light during February 2007 to January 2008. Small jellyfishes were collected by using 500 micron mesh net and density was calculated as number per 10 square meters. Large jellies were collected by using shrimp trawl net and quantity measurements were done by swept area methods. Totally, 18 species including 9 hydromedusae, 2 Scyphomedusae, 3 Siphonophorae and two Ctenophores were identified. Generally from 5357 separated small jellyfish, 56.6 % was from East and 43.4 % was from west coasts. Ctenophore, Pleurobranchia (31%) and then the Hydromedusa Eiren hexanemalis (22%) were the most abundant taxa. The maximum number of jellyfish (1080 per 10m^2) was observed in western coasts in July and then decrease in summer and autumn. In contrast to Eastern coasts, the highest frequency (655 per 10 m^2) was observed in western coasts in September. Two peaks of frequency in May-June and in summer to fall were observed in this area. The highest frequency of macro jellyfishes were in July and mostly in East coasts (2811 per km^2). During February 2007 to February 2008 Catostylos tagi and Chrysoara hysocello were dominated. Monthly jellyfish abundance variation showed inverse relation between Eastern and Western coasts. The maximum diversity was in August in Eastern coast and July in Western coasts. The minimum values were calculated in winter months in two areas. Obviously, with increasing jellyfish abundance, in summer months, fish larvae population decreased. Jellyfish explosion can be caused by several factors, fishing pressure and removing top predators from food web, climate change, global warming and eutrophication phenomena are defined as the major factors in jellyfish bloom in worldwide tropical coastal waters. Therefore human activities enhance the occurrence of this phenomenon. Recent drought, decreasing freshwater input, increasing waste discharge and overfishing are probable causes for jelly blooms in Khuzestan coastal waters

Identification and density determination of juvenile fishes in Khouzestan coastal waters

Aquatic animals possess specific biological characteristics and lifecycle. Without knowing about their biology and complete lifecycle, planning about their conservation cannot be effective. Following the previous studies on fish larvae in Khuzestan coastal waters this study was done to determination catch composition and density of juvenile fishes in Khuzestan coastal waters during 2007 to 2008. Studied area included two main fisheries ground, Lifeh-Busafe in west and Bahrekan in east coasts. Monthly random sampling was carried out by using shrimp trawl net with Akhtar vessel. Juvenile fish's means the fishes that completed their larval cycle and are look like their parents but have not been matured yet. The catch mean, biomass, CPUA and the stock size of different species were estimated by using Swept Area Method. Totally 101485 caught fishes included 38 families and 63 species. The most abundant trawled fishes were Thryssa vitriostris Leiognathus bindus Ilisha melastoma Penahia macrophthalmus and Johnius belangerii .These five species contain about 80 %, the species Arius dussumieri and Cynoglossus arel 4.5% and 3.2 % respectively and the others 12% of total caught fishes. In the east coasts the species L. bindus I. melastoma T. vitriostris P. macrophthalmus and in the west coasts the species P. macrophthalmus T. vitriostris J. belangerii and I.melastoma were the most abundant. Among 63 identified fish species , juvenile fishes of 23 species were observed which contain 26.4 % of total caught fishes .the fishes Arius dussumieri and Acantopagrus latus 100%, Liza subviridis, Leiognathus lineolatus and Triacantuhus biaculeatus more than 80 % and Pomadasys stridens Lagocephalus inermis Saurida tumbil and Thryssa vitrirostris more than 50 % were observed as juvenile stage. The most abundant juvenile fishes were T. vitrirostris L. bindus and Arius dussumieri respectively. The maximum (1852 kg/km^2) and the minimum (165 kg/km^2) values of CPUA were estimated in west coasts in July and December respectively. The maximum (2677 kg/km^2) and the minimum (153 kg/km^2) values of CPUA were estimated in east coasts in June and August respectively. The biomass showed a distinct peak in June and July in east and west coasts respectively. The highest diversity index in east (2/22) and west (2.36) coasts were obtained in July. In present study the number of identified fishes is more than previous studies. Juvenile fishes spend their sensitive period of lifecycle in Khuzestan coastal waters. After growing in late spring, fish larvae enter to the juvenile stage and select this productive area as nursery ground. Increasing of juvenile fishes in July is accordance with their reproduction season in studied area. The east coasts are deeper than the west and there are some differences in hydrological characteristics due to discharging of the rivers Bahmanshir and Arvandrood in west coasts. The peaks of abundance in east and west coasts were observed with a clear time interval. The higher CPUA in east coasts can be caused due to gradual migration of juvenile fishes from west to east during cold season

Species composition monitoring in artificial reefs area in Khuzestan coastal waters

This study was carried out in continuation of previous studies on artificial reefs monitoring in Khozestan coastal waters. The main purpose was the zoo species composition on and around the artificial reefs. Sampling was done from May 2012 to April 2013, from 4 stations in artificial reefs area. Reef structures were sampled by scuba diving. Physical and chemical parameters were measured and water quality status was determined by using WQS index. Zooplankton and macrozooplankton communities were sampled by 100 and 300 micrometer mesh size nets respectively. Benthic animal's samples from sediments around of the reefs body were collected by Ekman grab. Sediment characters, TOM and grain size were analyzed by using ignition loss and size series sieves methods respectively. Secondary production of macrobenthic animals based on dominant species length classes was estimated. Ichthyological information recorded by diver (census and video recording) and Gargoor traps were used for fishing effort calculation .Except for nitrite parameter (p<0.05) in different stations and silica parameters (p<0.05) in different months, other parameters were not shown significant differences in studied stations and months. The mean of zooplankton density was (914±52) N/m^3 and the Copepoda species were the most abundant group (235 ±10) N/m^3.Anosim analysis showed no significant differences in reefs specie composition. Different Crustacean groups were included more than 82 percent of macrozooplanktons communities. Among macrozooplankons, the mean density of decapoda, branchiopoda and copepoda were 302, 296 and 191.5 N/m3 respectively. The mean density of macrobenthic animals was 418±90.26 N/m^2 and mollusk, crustacean and polychaets were the most abundant benthic animals respectively. During the study period, total macrobenthos biomass 11.37 g-wet/m^2 and its mean value 2.84 g -wet /m^2, were estimated. Annual production for polychaets and crustacean groups 154g-wet/m^2 and 182 g-wet/m^2 were estimated respectively. Annual production of total macrobenthic animals was about 675 g-wet/m^2/y. According to sediment analysis, the range of silt-clay (8.7-95.6)% and seasonal mean TOM (4.47-13.25)% were calculated in studied stations. According to attached organisms biomass (wet weight), Cnidarian Anthozoa class with (88)% was the most abundant and then sponge (10)%, Cnidarian Hydrozoan class and arthropoda each one with 1% were included total attached organisms. Due to high biomass of Anthozoa species the most abundant mean was observed in spring season. The Malacostraca group especially Crustacean (72)% was the main mobile animals on reef bodies and then Echinodermata (Ophiurida and marine Orchids) (18)%, Mollusca (Bivalves and Gastropods) (4)% and Polychaets (3)% were the main mobile organisms. The range of Shannon diversity index was (3.22-3.46) and (2.44-3.38) in studied stations and months respectively. Totaly in studied area, the number 15 fishes species were observed and Sparidae family with 3 species were the diverse fish family. The fish Hamour (Epinephelus coiodes,Seranidae) (87)% was presented in all studied months and stations. After Hamour the Neopomacentrue sindensis and Diplodus sargus Kotschyi were the most abundant fishes. The maximum and the minimum of hamour catch per unit effort were in reef B in spring and reef C in autumn respectively .Data comparing showed that except for nitrite the other physical and chemical parameters were observed in the same range by 2005-2007 study. According to obtained results, Zoo communities in different part of ecosystem showed greater diversity than to past years and in comparing to mudflat coastal waters in Khozestan waters, new ecosystem has been created in the region. High diversity of different animal groups that were disperses in water column in early phases of its life and need to settlement to substrate to continuing the life were observed in area. Attached animals plays an important role in biological and ecological characters in the coastal area

Study on Mahshahr creeks (north of Persian Gulf) as protected area

In recent years MPAs (Marine Protected Areas) have been known as a flexible tool to improve fishery management as well as to preserve biodiversity in valuable coastal waters habitats. This study was conducted to selecting the sensitive and high potential area that are impacted by several environmental stress and associated habitats are being damaged in Mahshahr creeks in Northwest of Persian Gulf. Study was done in eight creeks from October 2005 to September 2006. Different biotic parameters such as phytoplanktons, zooplankton, macro zooplankton, benthic animals and fishes (trawled species) communities and also physico-chemical parameters and sediments heavy metals were investigated. Different parameters were sampled monthly or seasonal from each creek. Water samples with bottle sampler and sediment were collected by Peterson grab. Several ecological and biological indices based on heavy metals and benthic communities were used. Concentrations of heavy metals were measured by using voltammetric plarography method (Methrom 797). The range and mean concentrations obtained in mg/kg were 35.16-15.03 (27.01) for Cu, 171.41-65.57 (102.672) for Ni, 20.06-4.63 (13.22) for Co, 0.78-0.093 (0.22) for Hg, 379-65.07 (113.7) for Zn, 1.00-0.27 (0.559) for Cd and 29.72-7.09 (14.66) for Pb. To evaluate the levels of sediment contaminations, the background values of the different heavy metals were calculated and contamination factor for each metals and degree of contamination for each creek determined as well. Measured concentrations were compared with International standards. Ultimately the heavy metals contamination factors (Cf) can be arranged as follows: Hg> Zn> Cu≥ Ni> Pb≥ Co > Cd and according to contamination degree (Cd), different creeks can be arranged as follows too: Ghannam> Ahmady≥ Zangy> Doragh≥ Darvish> ghazaleh> Patil> Bihad Regarding the results some elements such as Hg, Zn and Ni, are at risk level and all of the studied creeks are classified in moderate degree of pollution except Ghannam showing considerable degree of pollution. The benthic invertebrates are a well-established target in evaluations of environmental quality status. The AMBI (AZTI,s Marine Biotic Index) was developed to determine the impacts and the quality status in softbottom marine benthic communities. All creeks are characterized by muddy bottom. Macrobenthic animals, according to their sensitivity to an increasing stress gradient, classified in five ecological groups. In present study due to appearance of dominant species such as Capitella sp and nematodes (as opportunist species), diversity values was reduced. Two way ANOVAs showed only seasonal significant differences in mean abundance (P<0.05, f=5.712, df: 3,21) and Richness index values (p<0.05, f= 4.975, df=3,21), while all of creeks showed similar biological characters based on benthic communities. According to annual, mean of AMBI (BC) all of creeks classified in ecological group III with slightly pollution, except Darvish that was placed in unpolluted category. In general, according to AMBI and BI values, The most creeks are classified in unpolluted (34%) and slightly pollution (34%) categories except Zangy, Doragh and Patil in summer and also Zangy and Bihad in winter that showed moderate to heavily pollution (32%). The results of chemical quality of sediments, Cf values, Cd values, AMBI Index and water quality and risk Indices have confirmed each other. In general, the Mahshahr creeks are classified in moderate to heavy pollution status. In addition, biological parameters of benthic communities and other biotic parameters have showndescending trend in ecological quality in all of the studied creeks. Communities. According to annual, mean of AMBI (BC) all of creeks classified in ecological group III with slightly pollution, except Darvish that was placed in unpolluted category. In general, according to AMBI and BI values, the most creeks are classified in unpolluted (34%) and slightly pollution (34%) categories except Zangy, Doragh and Patil in summer and also Zangy and Bihad in winter that showed moderate to heavily pollution (32%). The results of chemical quality of sediments, Cf values, Cd values, AMBI Index and water quality and risk Indices have confirmed each other. In general, the Mahshahr creeks are classified in moderate to heavy pollution status. In addition, biological parameters of benthic communities and other biotic parameters have showndescending trend in ecological quality in all of the studied creeks. We used of some criteria for evaluation of biotic potential or sensitivity and also to explain the ecological health level of studied creeks. Positive and negative criteria are classified in three level 1, 3 and 5 for low, moderate and high degree of conservation value respectively. According to gained points the creeks Darvish, Doragh and Ghazaleh in high level and creeks Ghannam , Zangy and ahmady in low level of conservation value were classified

Survey on ecological characteristicsof Horolazim wetland in Khouzestan (2012-2013)

Rregarding the potential and capabilities of different socio-economic, ecological and recreational, Hurolazim wetland is allocated as a special place in the collection of ecosystems and environment and the study of existing ecological conditions is necessary to protect and restoring management. In this study, monthly Samples of four stations (stations north of the road, Imam Reza (1) and south of the road, Imam Reza (2), in the Rofayeh area and stations Tabor (3) and the Shatt Ali (4), in the Shatt Ali area) were taken during the year from April to March 2012. Samples included physical and chemical parameters, phyto and zoo planktons, benthos, fish, and fishing status. Phytoplankton samples using sampling bottles from 0.5 meters below the surface were taken and counted based on alive unit. Zooplankton samples were collected by 100 micron mesh size plankton net from a depth of 1.5-2 meters. Benthic animals and sediment were sampled by Van Vin grab(0.125 square meters). One sample for benthos and one sample for grain size analysis and percentage of organic matter were sampled from each stations. In order to estimate the monthly depleted catches, data collected from the census in place and sampling was done at the time. Three fishing area has inspected randomly once every 15 days and active fishermen and caches were recorded in the prepared forms during the day. In this way, the number of observed boats, the average boat per day, the catches of the boats and CPUE were registered and total fishing effort was calculated monthly. In this study, 194 species of phytoplankton were identified. Diatoms with 85 species, Cyanophyta with 59 species, Chlorophyta with 31 species, Euglenophyta and Dinophyta with 18 and one species were observed respectively. The highest abundance frequency of phytoplanktons with 38.96 percent were observed in Tabar station (3), Diatoms with 46% has shown the highest frequency and then Cyanophyta (34.17%), Chlorophyta (16.39%), Euglenophyta (1.6 %) and Dinophta (1.58%) were included of the total abundance respectively. In the summer colonies of Cyanophyta were in high density. A total of 35 species of zooplankton have been identified. from Rizopoda, the species of Arcellidae and Centripyxidae families, from Rotifera, the species of Brachionidae, Lecanidae, Asplanchnidae and Philodinidae families, from Cladocera ,the species of Daphnidae, Sisidae and Chydoridae families and from copepods, Cyclopoda families have been observed that included about 98 percent of identified zooplankton. Respectively, Copepoda (39.9 %), Rotifera (34.71 %), Cladocera (22.38 %) and Rizopoda (0.843 %) were dominant groups. The species Brachionus urceolaris with average density of 7.29 individual per liter, is the most abundant species that included 17 % of total abundance frequency in the wetland. The higher frequency of crustacean zooplankton such as Copepoda and Cladocera could be indicated an environment more favorable conditions and expected to be good status of food in the Horolazim wetland. Among the known benthic groups, families, Tephritidae (85%) and Chironomidae (7 %) of the order Diptera and Ostracoda (2 %) from crustacean, were the dominant macrobentic groups Among the studied stations, Station South Road Imam Reza (2), and the station Shatt Ali (4), were the highest and the lowest abundance respectively. The mean abundance of macrobenthos in different seasons showed the lowest and the highest abundance frequency in summer and winter respectively. According to diversity indices, The stations Tabar (3) was the highest and the Station South Road Imam Reza (2), was the lowest value of diversity index. The results showed the higher than 71.84 % of Silt-Clay percentage in all stations, The highest value of sediments TOM in the Station South of the Road Imam Reza(2) in the winter and the lowest in station Shat Ali(4) in summer were recorded. Based on HFBI index the stations north of the road Imam Reza (1) and the station Shatt Ali (4) in moderate status and the stations south of the road Imam Reza (2) and Tabar (3) in good status were classified. In this study, 15 species of fishes belonging to 8 genera and 3 families were identified. It was noticed that 87.4 percent of all identified species in the wetland belonged to the Cyprinidae family. The results of previous studies in 2006 and 2008 in the Iraqi part of Hawizeh wetland showed that the most common fish species belonged to Biah, Karas, Hemry and Shelej that included 89.3 percent of total fishing in the current study .Finally, It is evaluated that changes in water regime of freshwater wetlands, controlled the environmental characteristics and conditions. That means water plays a decisive role in the vital characteristics of wetlands. Changes of quantity and quality of water may be associated with changing the quantity and quality of biotic fauna in wetland system. In the management and protection of a wetland system, it is necessary to adopt measures based on scientific principles and reasonable methods in order to protect water quality