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This study was carried out from March 1992 to Sept. 1993. During monthly sampling from 6 stations in two selected creeks (Ahmadi and Ghazaleh) in Mahshahr area, macrofauna and meiofauna were identified and counted. Also total organic matter of sediments was measured and grain size analysis was carried out. The results show that among macrofauna the dominant benthic animals were Polychaeta, Tanaidacea and Oligochaeta and their abundance was higher in spring and autumn. Among meiofauna, Nematoda, Foraminifera, Copepoda and Ostracoda were dominant and their abundance was higher in winter. T.O.M value was the lowest in winter and the highest in spring......

The limnological study of the Golabar dam showed that in the Glabar dam inspite of bing its early establishment due to high nutrient and organic matter is located in eutrophic stage. the pH as well as bicarbonate levels shows that buffering capacity of the lake is high and the value of inorganic and organic matter measured are not considered as limiting factor for warme and cold water aquaculture. In the plankton survey 44 species of phytoplankton and 25 species of zooplankton were identified. Cyclotella , Nitzschia, Synedra and Trachelomona from phytoplankton and Polyarthera , Keratella , Filinia , Pompholyx from zooplankton were the dominant spicies.the Bacillariophyta from phytoplankton with 76.5 percent and Rotatoria zooplankton to with 76.2 percent considered the highest abundant . The average frequency of phytoplankton and zooplankton were 5*106 and 723 individual per litter. The Shironomide and Tobificide were the only two bentic group were identified in reservoir wehre their mean frequced were 293.75 and 224.30 respectively. The average biomass of bentic organism were 1.44±0.97 gr/m2.In the survey 12 species of fishes were identified. The potential natural production have been estimated to be 2.8 to 15.5 kg for bentivorous fish and varied from 53 to 175 kg /hec for plankton consumer fishes .The low temperature in several months as well as ice covered of the lake surface in particular in the months of duty and Bahman are the limiting factor of either warm or cold water fish production.

Present study analyzed the stomach contents of individuals belonging to five fish’s species in order toInvestigate seasonal changes in feeding strategy and diet composition in the South coast of the Caspian Sea (Gilan and Mazandaran provinces) from late March until late May 2010 using the research ship Gillan and fishing with batoom trawl nets and fishing blades insoles bony fishes in the depths of less than 60 meters. The average length and the total weight of Rutilus frisii kutum, Rutilus rutilus caspicus, Cyprinus carpio, Liza auratus and Liza saliens respectively were 36/9 ± 8/5 cm , 562/9 ± 353/2 g, 23/2 ± 3/2 cm , 202 ± 101/6 g, 24/6 ± 8/1 cm , 249/8 ± 242 g, 32/2 ± 8/9 cm , 320/9 ± 242/8 g, 22/7 ± 2/6 cm and 82/9 ± 52/2 g repectively. Using the method of Shorygin and Costello highly nourishing food strategy and different species of fishes were studied. The results of this study showed that Rutilus frisii kutum fed generally of Balanus and Cerastorderma In order of importance after Bivalvia, Gastropoda, Crabs, Fish eggs, Filamentous alge in GI Rutilus frisii kutum presence, but feeding it of Bivalvia (in particular Cerastorderma) was much more than the other food. The results of present study showed that under the influence of compatibility and behavioral mechanisms, ecological, physiological and nutritional importance of Rutilus frisii kutum Bivalvia. The results of studies were showed that Bivalvia was feeding the dominant Rutilus frisii kutum , while the results of this study showed that despite Bivalvia present importance in feeding the of this species, it seems that its presence in such digestion decreased. As well as the dominant food of Rutilus rutilus caspicus was fish, but generally from Detrite fed. This study showed that feeding the dominant species of Cyprinus carpio, Liza auratus and Liza saliens of Detrite was. The most important food items after ditrit for the Cyprinus carpio in order of importance include the Bivalvia, Gastropoda, Oligochaeta, Abra ovata, Nereis, Fish eggs, Filamentous alge, was. The Liza auratus dietary habits also showed that after ditrit the most importance in nutrition related to Foraminifera, Porifera and Balanus, and for Liza saliens to Gastropoda, Bivalvia and Porifera. The results showed that the mullet the greater the intensity of feeding fishes than other species were, Rutilus frisii kutum in between of Cyprinidae the greater the intensity of feeding fishes than other species were (0/05 > P). The values of this indicator in the lower longitudinal in all fish species investigated were more than high longitudinal groups. The feeding intensity at different times of sampling for all species investigated showed that in all species at times extremely reduced the reproductive index (0/05 > P). As well as the diversity foods in the lower longitudinal in all fish species investigated were more than high longitudinal groups. In conclution, our results demonstrated Food strategy have changed based on physiological changes, metabolismi activity, behaviour, and the amount of food available. Iranian Fisheries Science Research Institute Published

Ecological health is the most important component of the biological health. Macrobenthos invertebrate are the most important organisms in aquatic ecosystems that are used for determination of biological health. Benthic indices base bye data simplifying and shows a set of biological variable as a quantified variable that made the interpretation of data easier, one of this indices is BOPA index that give from ratio of opportunistic Polychaeta to Amphipoda. The higher value of this index shows environmental pollution. The value of BOPA index showed significant difference between stations (p

In this study ichthyoplankton, phytoplankton, zooplankton, benthic and hydrochemistry parameters were studied. 9 out of 11 sampling stations were in the Gorgan Bay area and 2 of them were in the mouth of the Bay. Ichthyoplankton survey were carried out in 6 stations and the other surveys such as phytoplankton, etc were done in 11 stations in 2009. Gorgan Bay map and position of sampling sites are given at the end of material and methods section. Biomass and frequency of phytoplankton at different stations, months and seasons were calculated that are presented in Tables 1 to 3. Hydro-chemical parameters such as water temperature, air temperature, visibility, DO, BOD5, pH, Alkalinity (bicarbonate, carbonate and total), Hardness (calcium, magnesium), CL,EC, Salinity, N (nitrate, nitrite, NH_3), Phosphate were measured and results are shown Table 11. Biomass (mgr/m^3) and numbers (ind./m^3) of 47 genus of different phylum of phytoplanktons such as Cyanophyta, Chlorophyta, Pyrophyta, Chrysophyta and Euglenaphyta as well as different phylum of zooplanktons consist of Protozoa, Arthropoda, Rotifera and Cyliophora were estimated. Frequency of phytoplanktons (ind/m^3) was 131.2, 1.6, 65.3, 18.9 and 23.8 million respectively. Furthermore, their biomass was 308.4, 1.9, 1358.9, 295.1 and 124.7 mg/m^3, respectively. The maximum and minimum numbers were observed in Leptolingbaya belonged to Cyanophyta and Diatoms of Chrysophyta 84.3 and 0.025 million (ind/ m^3) respectively. The maximum and minimum biomass was observed in Gyrosigma (Chrysophyta) and Tetradron (Chloropyta), 12317.3 and 0.014 mg/m3 respectively. The average biomass of zooplankton was measured 531.74, 30.77, 225.07, and 96.26 mg/m^3 respectively and the total was attained 883.83 mg/m3 Table 5. The maximum and minimum biomass of all zooplanktons was estimated in November and July, 3446.23 and 6 mg/m^3 respectively. Furthermore, the maximum and minimum numbers of zooplanktons were found in September and July which were 48.4 and 0.002 millions respectively and the average number was 8.4 ind/m^3 Table 4. Also numbers and biomass (gr/m^2) of 11 families of benthos which inhabit Gorgan Bay such as Annelida, Mollusca and Arthropoda were investigated in separated stations and distinctive months. The maximum and minimum biomass of benthos was observed in January (42.91 gr/m^2) and March (0.6428 gr/m^2). The biomass was considerable in April, February, August and December (Tables: 4, 5 and 6).

Due to study the food regime of Arius dussumieri, a total of 132 specimens were collected from Oman sea waters, Sistine & Baluchistan province. The stomach content, were taken into consideration and it was found that the amount of full, semi-full and empty stomachs were 31, 33 and 36 percent, respectively; of which the highest frequency was in winter (74%) and the lowest was in summer (24%). On the other hand, the fullness index was studied with the highest and lowest value for spring (44%) and winter (5%), respectively. The GaSI shows that A. dussumieri, has better feeding in spring and summer but feeding (up in male) was decreased in autumn and winter. The Food Preference (FP) Index was estimated as: Fishes (39%), Crustacean (40%) and Molluscs (20%) namely all of them are considered as minor food in all four seasons. The most important food items were identification as fishes: Carangidae, Engraulidae & Leiognathidae; crabs: Portunidae & Porcellanidae; shrimp: Alpheidae; cephalopods: Loliginidae & Opisthoteuthidae; gastropods: Muricidae & Naticidae.

Neogobius caspius is a small benthic fish that is native to the Caspian Sea. The importance of this fish is because of it is role as a main food resource of the Sturgeon fish. The genetic diversity of N.caspius populations in the Caspian Sea was studied using microsatellite technique. In the study 95 Samples of Neogobius caspius from two regions (Torkman port and Chalus) in south Caspian Sea were collected. DNA was extracted using 12 pairs of microstellite primers polymerase chain Reaction (PCR) was conducted. DNA Bands were analyzed using uvdoct and GenAlEx software package. Out of 12 microsatellite primers, 11 loci were produced, in which 5 of them were polymorphic, 6 monomorph and one of them showed smear. Average of observed and expected hetrozygosity was 0.798 and 0/843 respectively. Significant genetic differences between 2 regions was observed (P

The present study was carried out to find the probable effects of marine fish cage culture on benthic communities as pollutant and stress indicators. Also, the biotic health condition was assessed using ABC index, in Ghazale creek, Khore-Mussa area in northwest of the Persian Gulf. Monthly sampling from four stations was conducted from June 2007 to March 2008. Stations were selected according to distance from cages in Ghazale creek. The distances were immediately under the cages, 50, 150 and 400m from the cages. At each station, three samples for macrobenthos and one sample for sediment grain size analysis and total organic matter (TOM) were collected by Van Veen grab with 0.0225m 2 area. The range of total organic matter percentage in sediments was (6.17-23.26) and the range of silt-clay percentage was (4.76-97.47). We found 12 macrobenthic orders and Polychaets (60.62%), Mullusca (19.67%), Crustacea (16.49%) were the dominant groups. Macrobenthic abundance, biomass and diversity index value under cage station were less than those 400m away from the cages. Capitella sp. as opportunist species was dominant under cage station. This genus is introduced as the pollution indicator in the area. The result of ABC index show that under the cages and distances 50 and 150m away from the cages have average pollution, while the 400m distance from the cage (control site) is unpolluted.

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

In the early 1980s, an alien ctenophore Mnemiopsis leidyi already known as a gelatinous zooplankton was transported (likely via ballast waters) to the Caspian Sea from its introduced or native water of the Black Sea or western Atlantic which caused negative impacts. In this report, distribution of M. leidyi, planktonic and benthic organisms had been investigated in the Southern Caspian Sea (Iranian waters) in 6 transects consisted of Lisar, Anzali, Sefidroud, Nowshar, Babolsar and Amirabad at 26 stations during 2005 and 2006. As a whole, 1422 samples had been analyzed included 258, 346, 217, 117 and 484 belong to ctenophore, phytoplankton, zooplankton, benthos and physicochemical parameters, respectively. M. leidyi abundance and biomass were fluctuated between 284-2751 ind.m^-2 and 16.9- 390/9 g.m^-2 respectively in 2005 while maximum abundance and biomass were recorded in autumn and minimum in winter. In 2006, its mean abundance and biomass were 184-2150 ind.m^-2 and 9.1- 209/8 g.m^-2 respectively. M. leidyi maximum abundance and biomass were noted in summer and its minimum in spring and winter months. Overall, mean M. leidyi abundance and biomass were recorded in 20 m within 1202 ind.m^-2 and 139.5 g.m^-2 respectively. Maximum size of the ctenophore was recorded as 55 and 60 mm in 2005 to 2006 respectively, while less than 10 mm length frequency consisted 83.16 and 82.88 per cent of total population. Spatial_ temporal distribution of M. leidyi in different regions showed it was more abundant in west and east (714- 4494 ind.m^-2) ratio to central parts (13-1519 ind.m^-2) of the Southern Caspian Sea. Species composition of zooplankton had shown the negatively impacts of M. leidyi invasion in the period of sampling as the only 17 holozooplankton were determined with Rotatoria (7 species), Copepoda (4 species), Ciliophora (4 species) and cladocera (1 species). Zooplankton maximum abundance and biomass were recorded in February (3039742901 ind.m^-3 and 372.1575.4 mg.m^-3) respectively and its minimum were in July (12211601 ind.m^-3 and 6.9 7.7 mg.m^-3) respectively which was belonged to Rotatoria (76%) and Copepoda (10%). In this study, 21 species of benthic fauna were deter minted belong to Pseudocumidae (5 species), Gamaridae (4 species) Amphartidae (3 species), Oligochaeta, Balanidae, Xantidae, Nereidae, Scarbicularidae, Carididae, Mytilidae, Herpobdellidae and Chironomidae (each 1 species). Oligocheata was recorded with maximum abundance (943 2502 ind.m-2) and Bivalve consisted of higher biomass (68.7162.5 g.m^-2). From five phyla of phytoplankton, 172 species were determined of Chrysophyta (74 species), Cyanophyta (32 species), Chlorophyta (32 species), Pyrrophyta (24 species) and Euglenophyta (13 species), in which Chrysophyta and Pyrrophyta were noted as main groups with their maximum abundance (up to 65%) and biomass (93%). Maximum water temperature was recorded in August with 29.52.5 ֯C and minimum in February by 9.31.3 ֯C. Mean value of salinity was 12.010.90 ppt, secchi disk ranged between 0.2 to 7 m and oxygen demand varied from 5.95 to 10.54 mg. l^-1). Moreover, silicate concentration was recorded between 200 to 300μg.L^-1, Phosphate measured from 31-47 μg.L^-1, Ammonia varied in 10-29 μg.L^-1, Nitrite (0.6- 1.7 μg.L^-1), Nitrate (0.06-4.20 μg.L^-1, which mainly accumulated in coastal waters of the southern Caspian Sea.

The Caspian goby, Neogobius caspius, is an endemic species of Gobiidae family in the Caspian Sea and it has ecological importance (as food for Caspian commercial fish such as sturgeons). The main aims of this study are, studying distribution, length, weight and age structure, sex ratio, diet, reproduction biology and morphological characters of this species in Guilan coast at waters of the Caspian sea and the sampling has been done monthly from Oct. 2005 to Sep. 2006 in 4 station from Astara to Chaboksar, with bottom trawl which had 12.5 meter length, 4.7 meter gape width and 2 mm mesh size in code end. The results showed N. caspius abundance is 9.82±11.93% of Gobiids and 7.92±10.10% of total fish numbers sampled in the study area (13824 specimens belong to 16 fish species) and there were significant differences among stations and seasons. CPUA of N.Caspius was estimated 52.5±105.9 ind/hec and 412.7±770.7 g/hec and there were significant differences among stations and seasons. Maximum body weight, total length and age were measured 65.10 g, 176 mm and 6 years old with an average 8.74±9.9 g, 84.83±28.4 mm and 1.83 years old, respectively and maximum age of males and females was 6 and 5 years old respectively and there were significant differences among stations and seasons and between sexes. It was estimated algometric growth model from length-weight regression, coefficient of K Von Bertalanffy growth model was estimated 0.42 and 0.68 in male and female, respectively. Sex ratio was 1.27 female to 1 male. Coefficient vacuity, relative gut length and intensity of 169 fullness were 8.72%, 0.76±0.17 and 267.7±263.3 for, respectively and Caspian goby fed on 30 different prey consist Zooplanktons (8 types), Benthic animals (15 types) and fishes (7 types) and young and yearlings have fed mainly mixed food (zooplankton and benthic animals) and adults on zoobenthose. Gammarids, Bivalvia, Cumaceae and Vormes constituted 44.7, 38.9, 24.8 and 19.7 % of prescence in full-gutted samples respectively, they were mainly preys (number and weight), hence this species is considered as euryphagus, carnivorous, benthphagus species. It was determined, Caspian goby spawns from March until last June, males and females take part in spawning in 2.8g and 65 mm and 1.3 g and 52 mm, respectively. Length at 50% maturity (LM50) was 80.2 and 77.5 mm in males and females, respectively. Maturity took place at 2 years old for both sexes, too. The absolute fecundity was estimated 109-1350 (451.6±216.3) eggs and relative fecundity 18-80 (36.8±9.2) eggs per one grams of body weight and diameter of ripe eggs was measured 1.31-2.60 (2.18±0.19) mm. Morphologically, there were 15 morphologically significant statistical differences between males and females and 15 differences among stations, sexual dimorphism was observed, too.

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

The Possible effects of dry years 1998-2000 on benthic organisms of Amirkalayeh Wetland was studied in the year 2001. Six sampling stations were defined where we seasonally collected benthics organisms using a grab sampler. We identified nine benthic organisms belonging to class Hirudina and orders Odonata and Ephemeroptera and also six families Chironomidae, Chaoborina, Ammaridae, Tubificidae, Xanthidae and Culicedae. Families Xanthidae and Culinidae had not been reported before for the wetland while orders Coleoptera and Trichoptera and families Planorabidae, Limnaeidae, Coleoptera which were present before the drought, were not detected in the samples. We observed a significant decrease in frequency of benthic organisms changing from 1372 organisms per square meter in 1997 to 165 in 2001. Also, tests showed considerable change in benthic diversity, species richness and distribution in different sampling seasons and stations over the year 2001. These changes may be attributed to the decrease in water depth, dissolved oxygen, available food and increase in water temperature and predation.