ALBERT

Description: This study was conducted to determine physico-chemical characteristics of water and their spatial and temporal fluctuations in the Mazandaran coastal of Caspian Sea in 6 months, four seasons at 4 transects (Tonekabon, Nowshahr, Babolsar, Amirabad) during 2012-2013. 72 samples were collected at surface layer of water in 5, 15 and 30m depths. Then the sampls analyzed based on standard methods. Results showed that the mean of water and air temperature were 19.46±0.85 and 20.25±0.78 ◦C, respectively. Minimum and maximum of water temperature were recorded in winter (7.00) and summer time (28.10). Mean of salinity was 12.35±0.13 ppt. The maximum salinity was recorded in summer and minimum in winter in all transects. Mean of transparency (SD) in the present study was 2.63±0.18m. The mean of pH was observed 8.51±0.02 which was higher than the pervious sampling periods. The mean of DO was observed 6.00±0.07 ml/l during sampling period. Annual concentration of dissolved inorganic nitrogen (DIN= NH4 +, NO2-, NO3-) has a fairly wide variation in diferents months and transects. Percentage of nitrogen components out of DIN were varied 6-53, 0.14-26.0 and 37.0-94.0 respectively. In this study, percentage of DIN was lower than 15% and dissolved organic nitrogen (DON) was higher than 80%. Mean of annual dissolved inorganic phosphorous (DIP) and organic phosphorous were 0.58± 0.04 and 0.48± 0.02 µM, respectively. DIP and DOP percentages recorded 54 and 46 respectively. Mean annual of dissolved silicon (DSi) obtained 9.5± 0.2 µM. Based on the results, the system was in phosphorus limitation during spring and summer but it shifted to nitrogen limitation in autuman and winter. Phytoplankton development was not limited by DSi at any seasons.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: The present project in related to survey of factors and hydrology and hydrochemical features (water temperature, dissolve oxygen saturation, pH, clearance, salinity, nitrogen, phosphorus and silicon) hydrobiology (zooplankton, phytoplankton, macrobenthos) and survey of bio environment pollution (oil, heavy metal, detergent) executed in lower 10m in different water larger in southern Caspian Sea in 2002-2003. For sampling 8 lines number were vertical on coast that selected from Astra in west to Gomishan in east in southern Caspian Sea basin. The result indicated the average physical factors such as pH were 8.11 and salinity12.12 ppt ,and disolve oxygen6.7 mg/l. Average chemical factors such as NO2 , NO3 and NH4 were 1.2 µg/l, 25.7 µg/l, 13 µg/l respectively.Total nitogen and organic nitrogen and inorganic nitrogen were 690.2 µg/l , 667.6 µg/l , 41.6 µg/l. Average silicat were recrded 266.35 µg/l . Total Phosphorus was observed 37.35 µg/l and average of organic Phosphorus concentration was and 20.25 µg/l .Average of Total organic matter (T.O.M) was 4.98% maximum amount were observed in Lisar and minimum in Nooshahr . Concentration of heavy metal during sampling were respectively ,Fe〉Mn〉Zn〉Cr〉Ph〉Co〉Cd〉Cu. Maximum concentration of Fe were determined in winter in Nooshahr and Babolsar respectively 13/3 µg/l 17/1 µg/l. In many stations and different Season, the amount of heavy meta were lower standard of in marine water. The concentration of oil hydrocarborate ( PAHs) in autumn was 0/13 ppb and in winter 0/12 ppb. The amount of ( PAHs) in Southern Caspian Sea were Lower than other parts of Caspian Sea. The average of detergent concentration ( LAS) was 0/036 µg/l that was two fold higher than determined in 2001. Total 107 species of phytoplankton belong to 5 phylum were identified. The numbers of species of phytoplankton groups were respectively, chrysophyta (42 species), cyanophyta (17 species), pyruphyta (17 species), chlorophyta (21 species) and euglenophyta (9 species). The maximum diversity of phytoplankton observed in summer and minimum in autumn. High diversity of chrysophta and cyanophyta observed in summer and phyrophyta and chrlophyta in spring. The composition of phytoplanhkton groups were respectively, chrysophyta (70%), phyrophyta (9%) and chlorophyta (7%) and euglonophyta (1%). Maximum density of phytoplankton was observed in autumn and minimum in winter. Total 19 species of Zooplankton were identified. Maximum diversity was observed in summer and minimum in winter. Zooplankton changes during sampling, showed amount of density of zooplankton in 5m were more than 10 m depths. Total (17 species macrobenthos were identified. The composition of macrobenthos groups were respectively , Annalida (92/7% ) , Bivalvia (2/7%) gumarida (108%) cumacea ( 1/5%) , Balanidae 103% . max . density were observed in Astara and min . in Sefied roud Average of density were 1218 0/851 ind /m2 and biomass 14 15 g/m2 High density were recorded in autumn and low density in winter . Correlation of phytoplankton and zooplankton with physicochemical parameter and also relation between total organic matter and sediment grain size were calculated.Ecological indicies (simpson diversity evenns diversity and shanoon-wiever diversity) were calculated for macrobenthos. Data were shown impact of cetenephora (Mnenemiopsis leidyi) on zooplankton and phytoplankton and macrobenthos density.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: The Caspian Sea is the largest lake, both by its area and volume. Zooplankton are very important in the food web since many animals eat them.The Sampling was done in 4 transacts in Anzali, Tonekaboun, Noushahr and Amirabad at 3 different depths including 5, 10 and 20 m. Sampling was carried out in four seasons of spring, summer, autumn and winter in 2013. The annual changes of zooplankton was between 392±113 ind./ m3 in autumn (Amirabad) to 8065±11735 ind./ m3 in winter (Amirabad). The lowest density of zooplankton in the spring was 2207 ind./ m3 in Anzali. The density of zooplankton in Tonekabon and Amirabad was 2.0 and 2.8 fold more than other transects respectively. The results showed that the abundance of zooplankton in summer was between 1964±470 ind./ m3 (Amirabad) to 5706±6088 ind./ m3 (Tonekabon). The biomass was 30.02, 52.22, 22.98 and 18.31 in Anzali, Tonekabon, noshahr and Amirabad respectively. The abundance of zooplankton in the autumn reached the lowest value. The lowest value was 392 ±113 ind./ m3 and 3.71± 0.19 mg/ m3 (Amirabad) and highest value was 2280 ±1435 ind./ m3 and 20.23 ± 14.50 5mg/ m3 (Anzali). The highest density was observed in Amirabad (8065 ind./ m3 ) and Anzali (8061 ind./ m3 ) in winter. The aim of this study was diversity, distribution, density and biomass of zooplankton in the southern of Caspian Sea.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: Limnologicalstudyof SabalanrunoffDamfor aquaculturecold water fish was conducted in sixtimesat fourstationsfrom JulytoDecember2009.Averageminimumandmaximumparametersmeasuredindifferentstationswere included water temperature, dissolved Oxygen, total hardness, electrical conductivity, pH, BOD5, COD,TDS, NH4, NO2, NO3, PO4, TN, TP, SiO2, respectively (10/3 ± 9/5-14 ± 8/7° C), (9 ± 1/2-11/4 ±2/1 mg/liter), (367 ± 19/8-381 ± 17/8mg/liter), (0/95 ± 0/07-1/05 ± 0/07 mz/cm), (8/3 ± 0/1-8/4 ± 0/1), (3 / 3 ± 1/14-3/88 ± 0/71mg/ liter), (15/5 ± 3/1-16/3 ± 3 mg/liter), (0/48 ± 0/04-0/54 ± 0/06mg/ liter), (0/08 ± 0/02-0/13 ± 0/07 mg/liter), (0/004 ± 0/003- 0/05 ± 0/1 mg/ liter), (0/6 ± 0/2-0/64 ± 0/29 mg/ liter), (0/19 ± 0/07-0/22 ± 0/07 mg/ liter), (10/48 ± 0/6-10/98 ± 0/54mg/liter), (0/39 ± 0/11-0/44 ± 0/18 mg/liter), and(9/9 ±0/6-11/1 ± 1/4 mg/liter). Averageminimumandmaximumof water heavy metalswas included of Cd, Pb, Zn, Fe, Cuand Ni respectively was measured as ND(No Deliver), ND, ND- 0/242, ND- 1/075, ND- 0/018andND- 0/014inmg/ liter. Alsoamong the16organochlorinecompoundsmeasuredthehighestamount of was belonged totoxinHexachlorine Benzene (1/5 mg/ liter). The results of theanalysis ofwater quality parametersshowed that parametersexcept ofCOD, TDS, PO4, TP, Zn, Fe andwater temperature, otherparametersdo not haveany restrictions foraquaculturecold waterfishin therunoffDam. Based on data results it was noticed that there was temperature restriction up to November at downstream and station 2 showed less temperature fluctuation and more suitable condition compared to other stations. BOD5 value was within the allowable range for growing trout, in which station 2 somewhat with lower volatility of value had the most suitable BOD5 condition.In the present study, the amount of TDS in the study area was somewhat higher than the limitation and since TDS values increased with distance from the dam, therefore station 2 had somewhat better conditions for fish farming.In addition the amount of EC in the study area, indicating the inappropriateness of it for various activities in the fisheries.Although none of the stations in terms of the amount of phosphorus didn't show favorable conditions for rainbow trout fish propagation, it appears between the researches stations, station 2 had the most favorable terms.The results of this study (regardless of the unseen), it seems that in August and September; Zn had overestimated value for cold fish propagation. Recent study showed that among heavy metals, Fe in water, sediments and fish was over limitation value. Also, Fe value was measured of 1.08 at station 4, which showed over normal value for cold fish propagation. Therefore, station 2 at downstream seemed to have suitable cold fish propagation due to lower Fe value. On the based on the recent study, planktonic biological index did not endorse water quality for fish propagation. In this study, aquatic plant such as Potamogetonpectinatus and Pheragmitiesaustraliswas found at water of higher and somehow polluted organic matter. Probably, based on the results it was noticed that downstream water of dam was polluted to organic matter. At the recent study, resisted maroinvertebrates to organic matter (Chironomidae) was consisted noticeable frequency compared to other sensitive invertebrates to organic matter (EPT).Statistically, it can be expressed that probably organic pollution resulted to increase of resistance invertebrates and decreased of sensitive groups. In recent study, EPT/CHIR index was measured 0.6 in station 2 and 1.74 in station 4. This ration was less to many other mountain rivers. As ETP sensitive invertebrates has higher sensitive to other groups with the regards of environmental condition and pollution, unpredicted increase of Chironomidae compare to sensitive groups resulted of EPT/CHIR value which showed environmental stress. In this study, HFBI index was measured as 7.49 at station 2 and 7 in station4. Based on HFBI index, station 2 was classified as a high organic pollution and station 4 with noticeable organic pollution. At the recent study, station 2 was catch more fish to station4. For instance, Squaliuscephalus and Alburnoides bpinctatuswere catch in station 2 and were not found in station 4. As a whole, Biologicalindicators whichwas includedPlanktonBioindicator, EPT / CHIR. ,HilsenhoffBiologicalIndicator, diversityanddistribution ofaquaticplantsandfish, showed water situation inrunoffDamrich inorganic matter. Finally, thestudy areawasapprovedfor fish farmabout 50tons and needs managementarrangementswiththeincreasedproduction rate.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: The survey sampled during the fourth stage of the season was in 1387. Sampling in eight directions perpendicular (transect) to the beach and 480 samples was performed. In each transect from Astara to the Turkmen 5 stations at depths of 5, 10, 20, 50 and 100 m were selected for sampling. The total number of 191 species was identified; Bacillariophyta category species number was 97, equivalent to %50.8, category of Chlorophyta 28 species, equivalent to %14.7, category of Pyrrophyta 26 species, equivalent to 13.6 %, category of Cyanophyta 25 species, equivalent to 13.1% and category of Euglenaphyta 15 species, equivalent to 7.9% of all species formed. Average abundance of phytoplankton was 27947500(SD=2465184) n/m3 . The average biomass was 125.51(SD=8.84) mg/m3 . Abundance and biomass in spring and summer, autumn and winter have been significant differences (p 〈0.05). The highest frequency was in winter, autumn, summer respectively and spring was (p 〈0.05) and The highest biomass in winter, fall, spring and summer was respectively (p 〈0.05). Bacillariophyta category has the highest abundance equal to 14390833 ± 16262.35 n/m3 (mean ± standard error) were equivalent to %51.49 of the total abundance, Euglenophyta category has the least density equal to 109791 ± 16262.14 n/m3 (mean ± standard error), which is equivalent to % 0.39 of total abundance were included. Also Pyrrophyta category has the highest biomass equal to 69.66 ± 5.53 mg/m3 (standard error ± mean) were equivalent to %53.14 of the total biomass and Chlorophyta category with an average of 0.68 ± 0.11 mg/m3 (mean ± standard error) have the lowest biomass, were equivalent to %0.54 of the total. Phytoplankton Categories in every season, with biomass and abundance have been different (p 〈0.05). Abundance and phytoplankton biomass in the upper layer and lower layer varies with depth of 50 meters (p 〈0.05). With distance from shore and depth increases, reducing the mean abundance and biomass were observed (p 〈0.05). The highest and lowest abundance of phytoplankton was observed at depths of 10 and 100 meters respectively. The maximum amount of phytoplankton biomass in surface areas of deep stations 20 m and the lowest biomass sampled at the deepest point of the station was 100 meters. Abundance and biomass of phytoplankton in the deep layers of the sample with significant difference (p〈0.05) . So that the highest abundance layers of 10 m, the surface layer of 5 m, 20 m, 50 m and 100 m, respectively(p 〈0.05), and the most biomass in the surface layers of 5 m, 20 m, 10 m, 50 and 100 meters, respectively (p 〈0.05). Abundance and biomass of phytoplankton in transects was significant difference (p 〈0.05). Most phytoplankton respectively transect Astara, Babolsar, Anzali Amirabad, Turkmen, Sefidrud, Noshahr, Branch was observed (p 〈0.05) and in terms of biomass, respectively transects Astara, Anzali, Sefidrud, Babolsar, Noushahr, Branch, Amirabad and Turkmen values were higher (p 〈0.05). Species diversity indexe (Shannon – Wiener) phytoplankton was equivalent to 2.92. Environmental conditions and nutrients in different seasons on these parameters influenced the way that species diversity was lowest in summer and in autumn, winter, and spring, respectively, species diversity increased.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: This survey was carried out by R/V Gilan with a conical plankton net of 100 micron mesh by vertical hauls at 8 transect in the southern Caspian sea. Transects were located at Astara, Anzali, Sefid roud, Tonekabon, Noshahr, Babolsar, Amirabad and Torkman in depths of 5, 10,20,50and 100m. Samples were taken in 4 seasons ( in each season 64 samples) in 2009. In this study 23 species formed the zooplankton community including 4 species of Copepoda, 8 species of Rotatoria, 2 species of Protozoa and 8 species of Cladocera. The meroplankton blonged to 2 species of Balanus sp and Lamellibranchiata larvae. The annual results revealed that the maximum abundance of Copepoda were 3612±4839 ind/m3 and 35/75 ±42/81 mg/ m3 in summer and decreased gradually since autumn and reached to minimum value in winter. The maximum abundance of Cladocera was 300± 383 ind/m3 in spring and reached to less than 4 ind/m3 in summer and autumn. The Rotatoria had high population (3775± 8632 ind/m3) in winter which consisted the zooplankton population with Copepoda. The Protozoa had no efficient role in zooplankton population of Caspian sea during the year. The zooplankton population was affected by Meroplankton and Lamellibranchiata larvae in spring and winter. The Copepoda contributed in zooplankton population only in summer and autumn. The maximum zooplankton abundance and biomass were in 5m depth which included 10209±8352 ind/m3 and 43/56±26/08mg/ m3 in spring, 8545±7127 ind/m3 and 73/59±56/65mg/ m3 in summer(10 m depth), 8427±6711 ind/m3 and 43/15± 29/59 mg/ m3 in autumn and 24426 ±26975 ind/m3 and 334/25±392/21 mg/ m3 in winter which decresed from surface to depth. The maximum abundance and biomass of zooplankton were 5119±6018 ind/m3 in east and 28/59±24/79 mg/ m3 in central area in spring, 6628±7117 ind/m3 in west area and 50/73±59/52 mg/ m3 in central area in summer, 5248 ±5489 ind/m3 and 31/16 ±31/22 mg/ m3 in west area in autumn and 11588±16191 ind/m3 and 131/02±193/61 mg/ m3 in west area in winter. The annual statistical analysis reveals that there is significant difference between Copepoda and Cirripedia population among seasons, sampling stations, depth and sampling layer (Kruskalwallis test, p〈0.05) and the total zooplankton populatin had no significant difference only between seasons (Kruskal-wallis test, p〉0.05). The Cladocera, Lamellibranchiata larvae and the Rotatoria had significant difference between seasons only (Kruskal-wallis test, p〈0.01).

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: The The Shahid Rajaei Reservoir- Sari is an important and large reservoir in Iran. The major objectives of dam instruction are flood control, irrigation purposes, and electricity power. However the dam is going to supply drinking water for the people. In order to prevent threats of unsuitable water to human health risks and economic losses, it is necessary to monitor the water quality before offering it to people. In this study, some of the physicochemical parameters and Chlorophyl- a, phytoplankton,microb and fungi of Shahid Rajaei reservoir were measured at 4 stations (Shirin Roud branch, Sefid Roud branch, the crossing point of branches, near the tower) during six sampling months (June, July, August, September, November and February) in 2012-2013. In order to water quality classification, the water quality index, trophic status, Shanoon and saproby indices of reservoir calculated and the results compared to different criteria and standards. The results showed that the mean (±Standard Error) of temperature, dissolved oxygen, pH, phosohate, amonium and nitrate concentrations and Chlorophyl a were 21.35 (±1.30) ºC, 10.48 (±0.37), 8.54 (±0.04), 0.050 (±0.004), 0.036 (±0.004), 0.75 (±0.03) mg/l and 18.00 (±7.23) mg/m3, respectively. In the present study, temperature between surface and deep layer was stratified in June and July, which the stratification was registerd 0.47 and 0.69 °C decreases with increasing of each meter depth in 15 to 30 meter culumn. But, these changes for each increasing meter of water depth were 0.2 to 0.26 °C in August and September, respectively, and finally was close to zero in November. In the warm months (July, August and September) with the formation of thermal stratification in the reservoir was formed oxygen stratification, but in the cold season (November and February), with vertical mixing of water oxygen and percent saturation of the reservoir was nearly homogeneous. TSI showed the maximum and minimum values at stations 4 (oligotrophic condition) and 2 (mesotrophic condition), respectively. The maximum and minimum monthly values of TSI obtained in July, August (eutrophic level) and September, February (oligotrophic level) respectively. Based on the Water Quality Index (WQI), the reservoir was in the “good” quality in whole months, .This class shows that the reservoir is suitable as source of drinking water through routine treatment of drinking water and the quality of water is rarely is low. Meanwhile the water is suitable for swimming and water recreation and survives of .sensitive fish and other aquatic species. Based on the results, 107 phytoplankton species were identified during the period of study. The species were classified in 8 divisions. Maximum and minimum values of mean (SE) abundance observed in July and January, 661 (±286) and 10 (±2) million cells/m3 respectively at the surface layer. The One way analysis of abundance and biomass data showed temporal significant variances (P〈 0/05), however the spatial variances of data were not significant (P〉 0/05). Bacillariophyta and Pyrrophyta formed more than 95% of phytoplankton. 3 dominant species namely, Cyclotella meneghiniana, Goniaulax polyedra and Ceratium hirundinella formed about 70% of phytoplankton aboundance. Comparison of diversity indices (Shannon and Evenness) showed higher values in May and January; however the indices reached its lowest level (0.58 and 0.16) in August. Water quality assessment using Shannon index showed the lowest quality of water (moderately to high polluted) in July and August. This index demonstrated the highest water quality (slightly polluted) at station 1 and 4 respectively. The results of the water quality assessment using Saproby index (based on the resistant phytoplankton species to organic pollution) also indicated to organic pollution of water in the months of summer. The saproby assessment in stations categorized most of the stations in “moderately polluted” class of organic pollution except at station 4 which was in "slightly polluted" class. In conclusion, the removal (transfer) place and time of water to the water treatment plants.are impratnt because of temporal and spatial variation of water quality due to changes of phytoplankton structure in Shahid Rajaee Reservoir. Meanwhile, the survey showed that physico-chemical parameters alone did not reflect the actual conditions of aquatic water bodies. Monitoring of aquatic ecosystems must be complemented by biological monitoring. Microbial survey showed that the maximum and minimum geometric mean of the total number of bacteria, in September (6101559 CFU/100ml) and February (3310 CFU/100ml) respectively. However in stations, the maximum and minimum count of this parameter obtained at stations 2 (455316 CFU/100ml) and 3 (40964 CFU/100ml) respectively. There were no viable count of total coliform in the months of May and June. However it’s counting reach to the maximum value in September. Clostridium perfrigens showed viable count in water sample during September. The results also showed no proportion of fecal streptococci in microbe account in the Shahid Rajaei Reservoir. It might be good sign of suitable water quality in term of no-contamination by old and resistant fecal microbes. Base on the total coliform count, water quality was suitable for swimming and source of drinking water in most stations and months. The coliform count increased in August and September in stations 3 and 4. In these 2 months the probability of new fecal contamination increased by warm blood animals in the reservoir. It seems that the environment in September is suitable for accession of old and resistant microbes such as Clostridium perfrigens. The results of sample analysis revealed that the fungal colony counts in the station 4 and 5 were significantly higher than those the other stations. Moreover, the minimum and maximum of the fungal colony counts wereobserved in August and February, respectively. The most commonly isolated genera were Aspergillus, yeasts (especially candida) Penicillium, Cladosporium, Mucor, Fusarium, Althernariya, sterile hyafe and Paecilomyces respectively. Finally, in order to prevent of occurrence of eutrophication, algal bloom, and control of microbial activities and organic phosphorus loading it is necessary to control the activities of the human societies around the dam or the rivers tributary.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: The water quality provides the valuable information about the available resources for human usage.The reservoirs are the important resources of surface water which could be considered as an appropriate water resource for irrigation, drinking water and also fish culturing. The Shahid Rajaei Reservoir- Sari is an important reservoir in Iran, which conducted to study on its water quality in this survey. In this study, some of the physicochemical parameters and Chlorophyl- a of Shahid Rajaei reservoir were measured at 4 stations (Shirin Roud branch, Sefid Roud branch, the crossing point of branches, near the tower) during six sampling months (June, July, August, September, November and February) in 2012-2013. The water quality and trophic status of reservoir calculated based on some reference values and the modified Carlson formula. The results showed that the mean (±Standard Error) of temperature, dissolved oxygen, pH, phosohate, amonium and nitrate concentrations and Chlorophyl a were 21.35 (±1.30) ºC, 10.48 (±0.37), 8.54 (±0.04), 0.050 (±0.004), 0.036 (±0.004), 0.75 (±0.03) mg/l and 18.00 (±7.23) mg/m3 , respectively. In the present study, temperature between surface and deep layer was stratified in June and July, which the stratification was registerd 0.47 and 0.69 °C decreases with increasing of each meter depth in 15 to 30 meter culumn. But, these changes for each increasing meter of water depth were 0.2 to 0.26 °C in August and September, respectively, and finally was close to zero in November. In the warm months (July, August and September) with the formation of thermal stratification in the reservoir was formed oxygen stratification, but in the cold season (November and February), with vertical mixing of water oxygen and percent saturation of the reservoir was nearly homogeneous. The results showed that the European authorities (OECD) trophic status varied between mezotrophic to hypertrophic during the sampling period at all stations. The comparison with the values listed in the references of Iranian dams based on transparency and chlorophyll variables showed similar results. However, phosphorus variable (due to limited for phytoplankton) was not showing the true conditions of trophic status. As a conlusion, trophic status of Shahid Rajaei dam based on Carlson trophic index (TSI) was obtained oligotrophic (May and October), mezotrophic (February) and eutrophic (August and September) condintion during diferent months. Therefore, water management of the reservoir was more attention during warm months.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: This study was conducted to physico-chemical characteristics of water in the Iranian coastal of southern Caspian Sea during four seasons at 8 transects (Astra, Anzali, Sefidrud, Tonekabon, Nowshahr, Babolsar, Amirabad and Bandar Turkman) during 2009-2010. 480 samples were collected at different layers of water and then analyzed based on standard methods. Results showed that the mean of water temperature were 18.67±0.32 and 17.82±0.43 ◦C at the surface and euphotic layer, respectively. Minimum and maximum of water temperature were recorded in winter (6.40) and summertime (27.60). In addition, temperature gradient was ranged between 12 to 15 ◦C at 20 to 50 layers in 50 and 100m depths. Mean of salinity was 11.04±0.17 g/l at euphotic layer. Pearson correlation between temperature and salinity was positively significant. Therefore, maximum salinity was recorded in summer and minimum in winter. Mean of transparency (SD) in the present study was 4.35±0.21 m which compared to the pervious sampling period (2008) showed small decrease, but the mean of pH was observed 8.43±0.01 which was higher than the previous sampling period (2008). The mean of DO and DO% were observed 5.72±0.06 ml/l and 130±1 percent at euphotic layer during sampling period. The mean of DO% was recorded 104±5 at euphotic layer in 1996 (before introduction of Mnemeiopsis leidyi), but the study in the years 2004, 2008 and present (one decade after introduction of Mnemeiopsis leidyi) this value was registered higher than 120% at euphotic layer. This shows that trophic status of Caspian ecosystem shifted from oligotrophy (before introduction of Mnemeiopsis leidyi) to meso-eutrophy (after introduction of Mnemeiopsis leidyi). Annual concentration of inorganic nitrogen (DIN= NH4 +, NO2-, NO3-) has a fairly wide variation. Percentage of nitrogen components out of DIN were varied 9-98, 0.2-28.2 and 0.0-90.0 respectively. In this study, percentage of DIN was lower than 15% and organic nitrogen (DON) was higher than 80%. Overall, results showed that water temperature, salinity, transparency and DON were recorded lower than the previous study (2008), but DO, DO%, pH, NH4+, NO3- and DSi were higher than the previous sampling period. Inorganic phosphorous (DIP) and NO2- have not changed substantially. N/P ratio of Caspian Sea has a narrow range which order of magnificent lower than other seas. The results of the present study showed that Caspian ecosystem was nitrogen limitation before introduction of Mnemeiopsis leidyi, while it seems that after introduction of Mnemeiopsis leidyi the system has been shifted to the phosphorous limitation.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: In this study, the characteristics of physico-chemical parameters of water done in coastal part of the southern Caspian Sea during 2010-2011 (four seasons) in 8 transects (Astara, Anzali, Sefidrour, Tonkabon, Noshahr, Babolsar, Amirabad and Torkman) . For measurement of water quality parameters, 480 samples were collected in different water layers by using of APHA standards methods. According to modeling and statistical methods was used multivariate for evaluation of factor analysis (MFA) in general groups and discriminant analysis (MDA) for spatial and temporal with water quality parameters. The statistical procedure of MFA was used for data reduction and finally six factors selected with about 80.48 percent of total variances related to them. The statistical procedures of MDA were used for the role of spatial and temporal of water quality parameters in different water layer. The function one gave eight parameters (pH, salinity, EC, DO, NO3-, water temperature, NH4+ and N-total) affording more than 80, 67, 80, 77 and 71 % correct assignations (return to the same transects) in spatial analysis. In all transects during four seasons, function one gave five parameters (water temperature, salinity, EC, NO2- and NH4+) to afford 100, 100, 100, 97 and 97 % correct assignations in temporal analysis. The results showed that, the average amounts in light penetration layers during four seasons were for EC(15.04±0.18ms/cm), pH(8.38±0.01unit), salinity (10.31±0.16g/l), DO(5.67±0.09ml/l) and water temperature (18.28 ±0.72°C). The average amount of nutrients for parameters such as organic and inorganic phosphorus, total phosphorus, NO2-, NO3-, NH4+, N-Total and SiO2 were 0.50±0.02, 0.32±0.01, 0.82±0.02, 1.76±0.10, 0.10±0.01, 1.51±0.10, 46.82±1.80 and 8.60±0.29µM, respectively. The average amounts in dark layers during four seasons were for EC (15.46±0.38ms/cm), pH (8.34±0.03unit), salinity (10.70±0.35g/l), DO (4.55±0.13ml/l) and water temperature (9.62 ±0.16°C). The average amount of nutrients for parameters such as organic and inorganic phosphorus, total phosphorus, NO2-, NO3-, NH4+, N-Total and SiO2 were 0.54 ±0.05, 0.33 ±0.02, 0.87±0.06, 1.92±0.21 , 0.08± 0.01, 1.55±0.25, 45.10±3.25 and 10.05±0.62 µM, respectively. The average amounts of light penetration in all transects during four seasons was 4.49±0.38 meters. The maximum light penetrations during spring, summer, fall and winter seasons were 9, 8, 8.20 and 7 meters, respectively. The maximum water temperatures in light and dark layers were 32.36 and 11.50°C. Also, the maximum differences about thermocline temperature during summer and fall seasons were 19.6°C and 10°C, respectively in southern part of Caspian Sea. Data in spatial analysis were not significant (p〉0.05), it means if add or removed any transect did not change occurred. But in temporal analysis were significant (p〈0.01), and it means no way remove any seasons for a research work on Caspian Sea in southern part. In those transects with 100m depth. Water temperature is only highly effective parameter between other parameters. In function 1 between 3 functions in transects with 100m depth water temperature with 60% variance was the main role and effective between different seasons in depth part were very high.

Description: Iranian Fisheries Science Research Institute

Description: Published