ALBERT

Description: This study was conducted to determine phosphorous and nitrogen species at the surface sediment in the southern Caspian Sea (Mazandaran Coast, Kelarabad). Surface sediments samples were collected at three stations from autumn of 2011 to winter of 2012. All samples were perpared by digesting and extracting processes and then phosphorous and nitrogen species concentrations determined using spectroscopy instrument. Results of this study showed that annual mean of Loosely-P, Fe-P, Al-P, Bioava.-P, Ca-P, TIP, Rese.-P and TP was obtained as 5.06±0.33, 55.11±2.52, 42.38±3.74, 102.52±5.68, 172.91±7.12, 275±9.12, 333.30±28.52 and 608±52 µg/g.dw, respectively. The results also showed that inorganic phophotous was less than organic phophorous during different seasons, however, mean percentage of residue-P containing organic compounds and non-degredable compounds was more than 50 percent. Percentage of Ca-P was higher than 60, whereas Bioava.-P was less than 40 percent. In addition, Fe-P and Loosely-P attained the maximum and minimum values, respectively, among the bioavailable phophorous. The order of different forms of phosphorous were recorded as Org-P〉Ca-P〉FeP〉Al-P〉Loosely-P. Annual mean of NH4/N, NO2/N, NO3/N, TIN, TON and TN were observed as 4.23±0.50, 0.06±0.01, 0.74±0.12, 5.02±0.53, 2.48±0.63 and 7.53±0.51 µg/g.dw, respectively. Annual percentage of TIN was two folds than TON and concentration of NH4/N was also four times than NO3/N. As a conclusion, the results revealed that main causes of Bioava.-P adsorbtion and desorbtion were temperature, Eh and pH. Also, the form of NH4+ /N was of a high percntage because of anaerobic condition in the sediments. According to the high ratios of nitrogen/phosphorous of sediments to nitrogen and phosphorous of bottow water, it finds that released of those from the sediments to water will be happned with high rates. Therefore, it is expected that the establishment of fish farming cages should be carried out with more precautionary approaches which not leads to increased algae bloom.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: At the present study, the environmental pollutants such as organochlorine pesticides (OCPs), heavy metals (during three seasons) and surfactants (during four seasons) were done 2009 to 2010 that located in Mangol Dam with longitude and latitude 52° 22' 49" N and 43° 15' 43" E, respectively. The aims of this study were to determine the seasonal pollutants matters in water samples of under-groundwater and surface water in 12 stations and the results are as follow: The maximum residues fluctuations of OCPs were determined in between all water samples such as aldrin and endrin about 1.51 and 2.85 µg/l, respectively. The mean concentration of aldrin and endrin about 0.66 ± 0.59 and 0.71 ± 1.07 µg/l, respectively were determined. The maximum seasonal concentration of OCPs were detected in fall, winter and spring for such as endosulfan sulfate, γ-BHC, heptachlor, endrin aldehyde compounds about 2.85, 0.34, 0.14 and 0.14µg/l, respectively. The maximum seasonal percentage range of OCPs were detected in fall, winter and spring in water samples such as endosulfan sulfate, DDD and β-BHC were 42, 25 and 25 %, respectively. The maximum seasonal concentrations of Zn and Fe elements were detected in spring about 1.12 and 8.22 µg/l, respectively. Also for Hg in spring was determined about 17.2 mg/l. The mean concentration of Zn, Fe and Hg in water sampled were 0.23 ± 1.01 and 1.21 ± 2.00 µg/l, respectively and 4.65± 6.38 mg/l. The maximum seasonal percentage range of heavy metals were detected in fall, winter and spring in water samples such as Ni, Zn and Fe were 66, 83 and72%, respectively. The maximum seasonal concentrations of heavy metal were detected in Sorkhroud and Polechelave stations during fall, winter and spring for only Fe about 1.48, 3.3 and 8.22 µg/l, respectively. The maximum concentration of linear alkyl benzene sulfonate (LAS) in last month of summer was 971µg/l. The mean concentration of surfactant during fall, winter , spring and summer was 418.62 ± 52.16 µg/l. The maximum seasonal percentage range of surfactant uring fall, winter, spring and summer in all stations of sampling were 76, 76, 100 and 100 %, respectively.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: This study was conducted to determine 16 Polyaromatic Hydrocarbons (16PAHs) concentrations in water (during four seasons) and surface sediments (during summer and winter) at eight transects (Astara, Anzali, Sefidroud, Tonekabon, Nowshahr, Babolsar, Amirabad and Turkman) in the southern of Caspian Sea in 20102011. 94 samples of water and 45 samples of surface sediments were collected at 10, 50 and 100 meters depths. In addition, 28 samples of fish (Cyprinus Carpio) were collected during winter and spring. All samples were prepared by Soxhlet and extracting processes and then determined using High Performance Liquid Chromatography (HPLC) instrument. Results of current study showed that mean concentration and standard error (±SE) of 16PAHs water were observed 232 (±77), 1268 (±808), 538 (±190) and 151 (±53) µg/l in spring, summer, fall and winter, respectively. In addition, annual mean contents and standard error (±SE) of 16PAHs water were registered 24.10 (±8.12) µg/l. The Hazard Quotation (HQs) were calculated more than unit and belong to Benzo(a)pyrene and Dibenzo(a,h)anthracene compounds. Mean concentration and standard error (±SE) of 16PAHs sediment were observed 0.77 (±0.23) and 1.21 (±0.64) µg/g.dw in summer and winter, respectively. Also, the annual mean contents and standard error (±SE) of surface sediments were observed 0.93 (±0.33) µg/g.dw. The Hazard Quotation (HQs) were calculated more than unit and belong to Fluoranthene, Benzo(a)anthracene, Chryseneand Benzo(a)pyrene. The annual mean contents and standard error (±SE) of edible tissue of Cyprinus Carpio mussels were observed 2.21 (±0.42) µg/g.dw. Annually, pattern of 16PAH compounds were obtained 10, 70, 12 and 8% for 3,4,5, and 6 rings, respectively. Four ring compounds had high content and percentage and 2 ring was not observed in all samples of water. Also, pattern of 16PAH in surface sediments were obtained 31, 56 and 14% for 3, 4, and 5 rings, respectively. Four ring compounds had high content and percentage and 2 and 6 rings were not observed in all samples of surface sediments during two seasons. Result of Diagnostic Ratios analysis (DRs) of sediments showed that the source of oil compounds were petrogenic and pyrogenic in summer and winter, respectively. Based on DRs in water and sediments were observed oil compounds were either petrogenic or pyrogenic with different percentage in the southern Caspian Sea. In conclusion, the results revealed that in the some transects the 16PAHs concentrations of water were above the threshold levels and more petrogenic (85%) sources which represented polluted condition in this area. 16PAHs concentrations of sediments were below the threshold levels and conditions for this region were showed unpolluted. Also, the Caspian Sea sediments were classified in Class 2 (Fair). According to results of the evaluation’s risks to human health associated with consumption of the mussels containing 16PAHs suggest that there is risk for humans.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: This study focused on identification phytoplankton, zooplankton, benthos, fishes and relationship between biotic and abiotic parameters at three stations in the Kan river during 2014. This study identified 19 phytoplankton taxa. The findings showed, the diatoms abundance were dominated in the river. The chlorophytes abundance were recorded the lowest abundance in this study. The nutrients and water temperature were the significant abiotic parameters to increase cyanophytes and chlorophytes abundance in the Kan river. This study identified 26 zooplankton taxa. The Rotatoria and Protozoa abundance were dominated in the Kan river. Based on CCA, there was no correlation between abundance zooplankton and abiotic parameters. The biodiversity index of plankton was between 1.8 and 2 and the lake situation is located in the mesotrophic category. The study of the Kan river fishes showed, only one endemic fish species Capoeta bohsei. The length (between 38 and 270 mm, average 144±86 mm) and weight (between 1.1 and 356 g, average 108.8±146.7 g) of the C. bohsei were varied during the study period. The 19 benthos taxa were identified. The Ephemeroptera was most abundant in the benthos groups. The classification of river based on biology indicator and environmental parameters confimed that water quality is located in the moderate category.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: Cheshmehkileh River and adjacent mountainous streams, play a strategic role as a historical axis for anthropogenic civilization, human welfare also habitat and migration pathway of commercial – biologic valuable fishes e.g. Caspian trout, Caspian kuttum, members of Cyprinidae family in south Caspian Sea drainage. Treats such as overfishing of Caspian trout and Red spotted trout stocks in mountainous headwaters, barriers construction and manipulations those are out of river carrying capacity developed by human activities, affected normal function of river as well. Sand mining big factories establishment next to the river, legal and illegal trade of river sediments, direct entry of Tonekabon landfill leakage into the river, development of Rainbow trout farms since 3 decades and huge effluents into the river containing dead fish and types of solids, escapement of cultured Rainbow trouts into the river, … are major minimum factors which needs basic information for integrating inclusively drainage management system. Cheshmehkileh River contains Headwaters of Dohezar (Daryasar & Nusha), Sehezar and Valamroud rivers during 13 monthly sampling phases between September 2009 and October 2010 based on macrozoobenthoses investigations by EPT, EPT/C EPA protocols, measurements of nominated physic-chemical and microbiologic parameters. Probability of Rainbow trouts escapement and invasion, existence, nutrition in Cheshmehkileh environment indeed investigated. Data analysis explained significant differences (P〈0.05) between groups of measured parameters in different sampling stations. Dendogram of clustered analysis based on consolidation of major biologic/ physic-chemical and microbiologic parameters, separated stations No. 1, 3, 2, 4 in one group and remained classified in different groups. Station 8 and 9 similarly separated which expressed general similarities according to Sehezar river environment which were differs in comparison with other stations. Station 11 separated according to its natural quality of water and environment. Similarities between station 10 to Sehezar river stations 8 and 9 expressed general influence of Sehezar River more than Dohezar River in Cheshmehkileh condition especially in station No. 10. High scores of EPT and EPT/C indices in upstream stations 1, 3 and 8 also low score of indices in stations 7, 13 and 6 expressed levels of environment quality between these groups of stations. Maximum average biomass of macroinvertebrates belongs to Trichoptera order in Cheshmehkileh River. Significant decrease of biomass in stations 11, 12 and 13 in comparison with other stations stated environment degradation in mentioned stations relevant to excessive sand mining as well. Pollution resistant groups of invertebrates significantly increased in downstreams against upstream stations. Also disappearing of Plecoptera order in station No. 7, 9, 10 and 13 stated low quality of environment in comparison with upstream stations. Confirmation of effects quality and quantity for point and non-point sources of imported pollutants require specific management considerations in order to present exploitations, pollutants control and emergencies for river monitoring in forthcoming years.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: Whiteleg shrimp (Litopenaeus Vannamei) is one of the most important species for aquaculture development, because of tolerance and adaptation to different ecological conditions.The aim of this study was determine the bionormative parameters of vannamei shrimp culture using Caspian Sea brakish water in Mazandaran province and also possibility of introduction a new aquatic spciese for rereaing in Mazandaran province. The Shrimp vannamei reared with the brackish water (10±0.43ppt) of the Caspian Sea in Mazandaran province and the Caspian Sea Ecological Research Iinstitute in summer 1391, 1393 and 1394. In this study, were evaluated the effect of different densities (45/m2, 50/m2, 55/m2 and 60/m2) primary stock whiteleg shrimp postlarvae (PL12) on the growth, survival rate and also population structure of phytoplankton in shrimp vannamei. Initially, post larvae in brackish water were gradually adopted. The density of 35 per square pieces in an earthen pond (1000m2) was stocking.The rearing time was 85 days. Average daily growths: 0.31±0.037g; final mean weight: 21.11±0.71; Feed conversion ratio: 0.79 and final yield: 531kg were determined. In addition the experiment of 1391, the results of Mazandaran province vannamei shrimp culture, were observed in 1393 and 1394, the average weight average daily growing and FCR % were 20-18 g and 0.68 - 0.77 respectively during 90 days culture period with harvesting of 40 PL /m2 at cement culture pond. The experiments of effect of different densities were performed separately in 1391, in 12 circular concrete pound with a sandy bed (area: 78m2) in the four treatments and three replications for each treatment. The experiments performed in a 75-day period. During the test, the water temperature was 27.4±1.79°C. The results showed that growth parameters and survival rate in experimental treatments, there was a statistically different (Duncan test, P〈0.05). Thus, with high levels of density, the amount of weight gain and survival rate (SR), specific growth rate (SGR) and daily growth rate (ADG) has decreased. In addition, the treatments were different variations of FCR (P〈0.05) and not depend on the primary stock density of postlarvae. The highest growth (SGR=11±0.04 and ADG=0.25±0.01) and survival rate and calculate the amount of production per hectare (5596±433) were observed in low density (45m2). In this study identified 20 genera of phytoplankton from five division of the Phytoplankton. Phylum Cyanophyta, with 30 percent of the identified genera that much more constituted. And the phylum Chlorophyta with 25 percent, of Bacillariophyta 20 percent Pyrrophyta 20 percent and Euglenophyta 5 percent had the lowest frequency. Chlorophyta with 25 percent allocated to the division, with 20 percent of Bacillariophyta, with 20 percent of the division; Pyrrophyta Euglenophyta division with 5 percent had the lowest frequency.Euglenophyta phylum was identified as a species. Therefore, based on acquired results, was observred that, vannamie shrimp was reared well using Caspian Sea brakish water in Mazandaran province. In addition, it seems that, vannamei shrimp was gained better results in Mazandaran province compared to other provinces, because of suitable water salinity.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: At the present study, the environmental pollutants such as organochlorine pesticides (OCPs), heavy metals, hydrocarbons and surfactants were done during 22 months (Sept. 2009 through May 2011) located in southern part of Caspian Sea with longitude and latitude 48°-54° N and 36°-39° E, respectively. The aims of this study were to determine the seasonal pollutants matters in water layers and bed sediments of eight transect (24 stations) and the results are as follow: The maximum seasonal percentage range of OCPs were detected in spring water samples from 10, 50, and 50m depths such as (DDD, δ-BHC, heptachlor epoxide, endrin aldehyde),(DDD) and (aldrin, β-endosulfan) compounds about 62.5, 75 and 100%, respectively. The maximum seasonal residues fluctuation of OCPs were determined in spring water samples from 10, 50, and 50m depths such as aldrin (Babolsar station), aldrin (Tonekabon station) and heptachlor epoxide (Astara station) compounds about 5.03, 3.08 and 31.43 µg/l, respectively. The maximum percentage range of OCPs were detected in sediments samples from 10, 50, and 50m depths such as aldrin and α-BHC (winter), α-BHC (summer and winter) and aldrin (summer) compounds about 100, 75 and 87.5%, respectively. The maximum residues fluctuation of OCPs were determined in sediments samples from 10, 50, and 50m depths such as α-BHC (summer in Nushahr station), α-BHC (summer in Sefidroud station) and α-BHC (winter in Tonekabon station) and compounds about 5.96, 3.77 and 3.07 µg/l, respectively. The fluctuation and distribution of Total Petroleum Hydrocarbons (TPHs) concentration in different water layers samples were reduced from summer〉spring〉 fall 〉 winter, respectively. Also this trend occurred for bed sediments and reduced from winter 〉 summer, respectively. The mean concentrations of TPHs in water samples of all seasons, regions, depths and transects were less than maximum permissible concentration (MPC). In this research, a comparison of TPHs with EPA standards shown that the desile range organic (DRO) was close to EPA standards such as TPHs and also 95 percent of water data were less than MPC. But gasoline range organic (GRO) concentrations in all stations were less than the amount of EPA standard. A comparison of TPHs concentration in sediments shown that the concentration of all stations were less than of national research council (NRC) range except west part. The maximum annual mean concentrations of Hg and Pb elements were detected in surface station (50m) at Nushahr and Amirabad transects. The most water data of Cd, Pb and Hg elements in comparison with critical concentrations with Europe, the USA and Japan standards were less than amounts of those standards. The distribution and abundance of Cd, Pb, Hg and Ni elements in water samples were detected 98, 96, 77 and 6%, respectively less than the ISQGs (Interim marine sediment quality guidelines) standards. In sediments samples, the mean and maximum concentration of Hg element detected in winter in comparison with ISQGs standards was more. But the concentrations of Cd and Pb in sediments samples of all stations were low and less than of ISQGs standards. The maximum concentration of linear alkyl benzene sulfonate (LAS) from spring through winter in Anzali (spring), Tonekabon (summer), Anzali (fall) and Nushahr (winter) were 0.07, 0.45, 0.145 and 0.087 mg/l, respectively. The maximum concentrations of LSA were detected in spring and fall in west part and summer and winter in middle part. But the lower concentration was occurred in west of southern part of Caspian Sea. According to standards of surfactants and comparison with LAS concentration of this study were less than the critical points.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: In this stydy, 486 species belonging to 12 divisions were classified in the Caspian Sea (Iranian waters). The number of dominant species in each division and the percentage of that, such as Baccillariophyta, Chlorophyta, Cyanophyta, Pyrrophyta and Euglenophyta were 186 (38%), 110(22%), 80 (16%), 71 (14%) and 28( 6%) respectively. There were a few numbers of Exanthophyta, Chrysophyta, Haptophyta, small felaggelate Ochrophyta and Cryphophyta divisions. The numbers of these divisions’ species are ranged from 1-5 species. In Baccillariophyta, genera such as Navicula ( 24 species,15%), Nitzchia (22 species, 13%) and Chaetoceros (18 species, 11%) were dominante. In Chlorophyta division, The highest number of taxa belonged to Oocystis genus, which included 10 species and comprasing 16% of predominant species. Scenedesmus genus is in the second place ( 9 species , 14% ). In cyanophyta, the number of species, Anabaena, Oscillatoria and Microcystis are 9, 9 and 7, and 17%, 17% and 13 %t of all predominant species. In Pyrrophyta division , Peridinium genus with 11 species and 22% is dominant. Glenodinium and Gymnodinium are ranked after Peridinium. From Euglenophyta, genera such as Euglena and Trachelomonas are dominant. The number of species are 13 and 11species respectively. Euglena genus comprising 50% of all dominant species. A total of 807 phytoplankton species were distinguished in inland waters ecosystems. 284 species(36%) Baccilariophyta, 241 species (30%) Cholorophyta, 144 species (18%) Cyanophyta, 59 species (7%) Euglenophyta, 57(7%) pyrrophyta are listed in database. Divisions of Chrysophyta, Exantophyta and Cryptophyta have a few numbers (6,4 and 3 respectively).from Baccilariophyta, Nitzchia and Navicula with 45 and 28 species make up 23% and 14% of the dominant species, respectively. In chlorophyta division,genera such as Scenedesmus ( 30 species ranking first place among dominant species) and Cosmarium (18 species second place) are distinguished. From Cyanophyta, genera Phormidium, Chrococcus, Oscillatoria and Lyngbia have the highest number of species that have 13, 12, 9 and 9 species respectively. These species accounted for 12%, 11%, 9% and 9% of dominant species respectively. In Euglenophyta, Euglena and Trachelomonas are dominated. These genera accounted for 21 species (39%) and 15 species ( 28%) of dominant species. From Pyrrophyta, Peridinium genus is dominant which includes 30% of dominant species. Gymnodinium with 8 species ( 17%) is in the second place.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: The project investigates the relationship between the biological parameters (phytoplankton, zooplankton, Macrobenthic and the comb jelly Mnemiopsis leidyi) and environmental parameters, nutrients and environmental pollutant (oil, pesticides, heavy metals, and detergents) in water and sediment, at the southern part of Caspian Sea in 2009-2010. Sampling was performed in four seasons (spring, summer, autumn and winter) and in eight transects perpendicular to the coast in Astara, Anzali, Sefidroud, Tonekabon, Noshahr, Babolsar, Amir Abad and Turkmen. Samples were collected from depths of 5, 10, 20, 50 and 100 meters and the different layers. The relationship between biological and environmental parameters surveyed through parametric and multivariate methods. Based on the result, the annual mean of environmental parameters and nutrients concentration at euphotic layer such as water temperature, salinity, pH, transparency, DO%, ammonium, nitrate, inorganic nitrogen (DIN), organic nitrogen (DON), inorganic phosphorus (DIP), organic phosphorus (DOP) and soluble silicon (DSi) were 17.82±0.32 (ºC), 11.35±0.10 (g/l), 8.43±0.01 (m), 126±1 (%), 3.76±0.19 (µM), 1.55±0.07 (µM), 4.81±0.13 (µM), 29.88±0.66 (µM), 0.24±0.01 (µM), 0.62±0.02 (µM), 8.22±0.22 (µM), respectively. Meanwhile, annual mean of environmental pollutant such as TPH, OCPs and LAS in water were 12.33±1.76 (µg/l), 2.85.0.90 (µg/l), 0.048±0.003 (mg/l), respectively and for TPH and OCPS in sediment were recorded 33.07±9.36 (µg/g) and 2.64±0.34 (µg/g), respectively. In addition, annual mean of heavy metals such as Ni, Hg, Pb and Cd at water were 4.01±0.01 (µg/l), 0.64±0.01 (µg/l), 15.0±0.1 (µg/l) and ND respectively, and in sediment were obtained 43.77±3.55 (µg/g), 0.13±0.29 (µg/g), 14.14±1.07 (µg/g) and 0.07±0.06 (µg/g), respectively. Abundance annual mean of biological parameters such as phytoplankton, zooplankton and M. leidyi were 143±12 (million cells/m3), 6548±700 (individuals/m3) and 86±10 (individuals /m3) respectively, and for biomass were 548±41 (mg/m3), 60±9 (mg/m3), 5.06±0.65 (g/m3). Abundance and biomass annual mean of macrobenthic were 5970±460 (individuals /m2) and 44±10 (g/m2), respectively. The stratification of water column was strongly based on gradient of water temperature and the rule of salinity was low in this area. According to mono and multivariate statistical analysis, the southern of Caspian Sea experienced four seasons without any overlapping based on environmental parameters and nutrients. In 2009-10, the nitrogen concentration was higher than previous years and showed a decrease in the amount of inorganic phosphorus in the study area. Therefore, the system has been lead to phosphorus limitation. No limitations of the DSi in the Caspian ecosystem had caused the dominance of bacillriophyta phylum during spring, autumn and winter. However in summer (highest seasonal mean temperature) which held the most DIP, the cyanophyta was dominant phylum. During spring and winter, the abundance of zooplankton was maximized and conversely the minimum values observed during summer and autumn with growth increasing of M. leidyi. By now, M.leidyi has been preferred the time with highest temperature or salinity during year. However with considering PCA analysis result and high ability of the organism to adaptation, the M.leidyi will probably to growth and reproduce at lower temperature and salinity than now in this area. Result showed that during summer and autumn only abundance of two of six main zooplankton groups namely Copepoda and Cirripedia were noticeable. The other zooplankton groups were low due to high consumption by different predators or were influenced by environmental factors. The dynamics population of M.leidiy is used to consider as first explanation of the Caspian ecosystem happening, however the interaction of different factors such as temperature, salinity, nutrients and predators determine the dynamic of biological parameters. Based on statistical analysis, feeding behavior of zooplankton species was not same in different seasons and was strongly dependent on the phytoplankton structure (species diversity and population). In other words, the classical boundary of phytoplankton species to, edible and suppressed, non-edible and unaffected and finally non-edible, enhanced species was not possible. Copepoda can act as filter-feeder and raptorial-feeder. So Copepoda compare to Cladocera (generally filter- feeder and sometimes raptorial feeder) and Rotifera (mostly suspension feeding and sometimes raptorial feeder) had more chances and opportunities for the achievement food and it support them for dominanane in all seasons. Anthropogenic and eutrophication affect on the structure and function of plankton community and it reflected on ratio of phyto/zoo biomass. Seasonal increasing of different groups of zooplankton were done through their life cycles in 2009-10, but mostly phytoplankton abundance increased several folds than zooplankton populations. This trend made the ratio of phyto/zoo biomass at 10, 4, and14 during spring, summer and autumn, respectively. In summer, with stratification of water column and dominant of Cyanophyta, grazing pressure by herbivores zooplankton was low. However in winter due to the zooplankton population growth, the ratios reached to 11, and declined with 1.3 folds compare to autumn. Because of severe decreasing of zooplankton biomass in 2009-10 compare to years before introduction of M.leidiy in to the Caspian Sea, the ratio of phyto/zoo biomass increased from "less than" 5 "to more than 10" Top-down control of zooplankton grazing on phytoplankton populations was clear in the years before the introduction of M.leidyi in to the Caspian Sea. But in 2009-10 zooplankton Shannon index reduced and phytoplankton Shannon index increased. In other word higher functional diversity at the lower trophic level (phytoplankton) increased the probability of successful defense against top-down control from zooplankton and phytoplankton abundance controled mainly by nutrients materials (down-top control). Seasonal macrobenthos abundance showed the maximum values in summer and minimum in the cold season (winter). The polychaeta had the highest proportion of abundance compare to others main orders (oligochaeta and crustacea). The dominance of deposit feeder species of polychaeta indicates to high level of organic matter in sediment and trophic status of ecosystem. Result of CCA analysis showed that three dominant orders had different behavior respect to environmental and sediments characteristics. The oligochaeta order was directly related to sediments characteristics (TOM) and inverse relationship with environmental parameters at most seasons. In contrast, polychaeta order was linked with environmental parameters in most seasons.Crustacea order was related to the both of them. Two orders of oligochaeta and crustacea were also related directly to OCPs and inverse relationship with TPH and heavy metals. In the other words, the two orders were more affected by TPH and heavy metals in this area. As a last point, increasing of trophic level from oligotrophic to the meso–eutrophic status, an increase of DO% from 105 percent to 120 percent, phytoplankton Shannon index increasing, zooplankton Shannon index decreasing, entrance of the potentially invasive species to the list of dominant phytoplankton species, increasing of phyto/zooplankton biomass ratio from less than 5 to more than 10 and also increasing of deposit feeder species abundance of macrobenthos are some evidences that indicate to disturbance and stress condition of the Caspian Sea.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: At the present study, the environmental pollutants such as organochlorine pesticides (OCPs), heavy metals (during three seasons) and surfactants (during four seasons) were done 2009 to 2010 that located in Mangol Dam with longitude and latitude 52° 22' 49" N and 43° 15' 43" E, respectively. The aims of this study were to determine the seasonal pollutants matters in water samples of under-groundwater and surface water in 12 stations and the results are as follow: The maximum residues fluctuations of OCPs were determined in between all water samples such as aldrin and endrin about 1.51 and 2.85 µg/l, respectively. The mean concentration of aldrin and endrin about 0.66 ± 0.59 and 0.71 ± 1.07 µg/l, respectively were determined. The maximum seasonal concentration of OCPs were detected in fall, winter and spring for such as endosulfan sulfate, γ-BHC, heptachlor, endrin aldehyde compounds about 2.85, 0.34, 0.14 and 0.14µg/l, respectively. The maximum seasonal percentage range of OCPs were detected in fall, winter and spring in water samples such as endosulfan sulfate, DDD and β-BHC were 42, 25 and 25 %, respectively. The maximum seasonal concentrations of Zn and Fe elements were detected in spring about 1.12 and 8.22 µg/l, respectively. Also for Hg in spring was determined about 17.2 mg/l. The mean concentration of Zn, Fe and Hg in water sampled were 0.23±1.01 and 1.21±2.00 µg/l, respectively and 4.65±6.38 mg/l. The maximum seasonal percentage range of heavy metals were detected in fall, winter and spring in water samples such as Ni, Zn and Fe were 66, 83 and72%, respectively. The maximum seasonal concentrations of heavy metal were detected in Sorkhroud and Polechelave stations during fall, winter and spring for only Fe about 1.48, 3.3 and 8.22 µg/l, respectively. The maximum concentration of linear alkyl benzene sulfonate (LAS) in last month of summer was 971µg/l. The mean concentration of surfactant during fall, winter, spring and summer was 418.62±52.16 µg/l. The maximum seasonal percentage range of surfactant uring fall, winter, spring and summer in all stations of sampling were 76, 76, 100 and 100 %, respectively.