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Showing 24 results for Biomass
S. Bebekam , A.m. Abedian , H. Younesi ,
Volume 19, Issue 4 (1-2011)
Abstract
We investigated production of single cell protein (SCP) from stickwater of kilka fish meal factory as medium using Lactobacillus acidophilus and Aspergillus niger. Stickwater was used instead of the standard media of bacterium and fungus in a batch culture method. Amount of biomass, COD, RNA and protein in the bacterium and fungus in control and stickwater treatments were investigated. In maximum growth time, amino acids profile of the bacterium and fungus were measured and compared between treatments. Bacterial biomass production in the control and stickwater treatments were 3.16 and 5.12g/l, COD reduction was 33270 and 53330mg/l, the measured RNA were 15.27% and 15.04%, the amount of protein were 71.13% and 68.37%, respectively. The difference between bacterium and fungus biomass production was slight. We found that the amount of the fungus biomass in control and stickwater were 6.31 and 7.28g/l, COD reduction were 47800 and 55200mg/l, RNA was 9.36% and 9.09%, the amount of protein were 51.36% and 48.66%, respectively. In both bacterium and fungus, the maximum and minimum amount of amino acid of the control and stickwater was glutamic acid and methionin. The amount of methionin in bacterium was not different with fish meal and FAO reference and in fungus was a little lower than FAO reference. According to the results, application of pure stickwater was suitable for production of Lactobacillus acidophilus and Aspergillus niger.
N. Jahani , S.m.b. Nabavi , S. Dehghan Madiseh , S.r. Seyed Mortezaie ,
Volume 19, Issue 4 (1-2011)
Abstract
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 0.0225m2 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.
M. Tavoli , M. Islami , S.m. Mahdavi ,
Volume 19, Issue 4 (1-2011)
Abstract
The changes in density and biomass of macrobenthos were seasonally investigated from winter 2005 till fall 2006 in southern Caspian Sea. Samples were taken with a 225cm2 Van Veen grab from depths of 7 and 20 meters along two transects: Line 8 area (western part) and Radio Darya area (eastern part). Totally, 5 classes of macrobenthos were identified of which the most abundant populations were Polychaeta 68.7%, Oligochaeta 14.6%, Bivalvia 8.5%, Crustacea 8.2% and Gastropoda 0.08%. The maximum density (4251.8 1419 (ME SE) ind/m2) of macrobenthos was observed during summer in the depth of 20m of Radio Darya area, while the minimum density (725.9 64.5 (ME SE) ind/m2) was observed during spring in the depth of 7m in the same area. Between the two studied depths, the mean annual density in 7m depth (2266.7 350.3 (ME SE)ind/m2), was higher from 20m depth (1977.8 290.1 (ME SE)ind/m2). The maximum biomass (475 243.8 (ME SE)g/m2), of macrobenthos was observed during autumn in the depth of 20 meter of Radio Darya area, while the minimum biomass (0.3 0.1 (ME SE)g/m2), was observed during winter in the depth of 7m in the same area. Between the two studied depths, the mean annual biomass in 20m depth (184.8 24.6 (ME SE)g/m2), was higher from 7m depth (73.7 24.6 (ME SE)g/m2). Generally speaking, the eastern part of Chalus coast had more density and biomass compared with the western part. *Corresponding author
N. Niamaimandi ,
Volume 20, Issue 1 (4-2011)
Abstract
Stock assessment of edible bivalve, Solen brevis was carried out in Bushehr shoreline areas (50 21 E - 29 41 N to 52 41 E 27 17 N) throughout the period of September 2008 till September 2009. The objectives of this study were identifying the distribution, and estimating the abundance, growth parameters and natural mortality of the bivalve. Solen specimens were collected monthly in Bupatil area and from three other areas at low tide. On each transect one or two quadrats (0.25m2) were placed at random. To estimate the stock abundance, the mean number of shells in each quadrat was regarded as an estimate of stock mean. Length frequency was used to estimate growth and natural mortality parameters. Data analysis was conducted with the most recent version of LFDA statistical software. The main distribution areas for live edible bivalve, Solen brevis, were located at Bupatil, Gasir, Kaloo, Piazi and Bordekhoon. The mean (±SD) abundance in Bupatil was estimated at 3.25 1.1 shells per quadrat with a maximum peak in October and minimum in August. The estimated growth parameters of this species was, K = 0.7 Year-1, L = 120 mm and t0 = -0.35. Natural mortality rate (M) was estimated at 0.26 and the calculated maximum age (Tmax) was 54 months.
M. Safaie ,
Volume 21, Issue 3 (10-2012)
Abstract
The Chaoo Sharghi is located nearby mangrove forest in northwest of Qeshm Island, in the northern Persian Gulf. Given standing in migration of juvenile shrimps, this area is one of important regions in Hormozgan Province. This study aimed to determine population dynamics of major shrimp stocks by swept area method in this area. Sampling was carried out monthly since March 2009 to June 2010. The average of carapace length frequency of Banana, Jinga, Kiddy and Peregrine shrimps showed that upswing from January to April. However, shrimps were predominantly juvenile. The annual growth coefficient (k) of female and male was 1.5 and 1.1 for F. merguiensis, 1.3 and 1.2 for M. affinis, 1.1 and 1 for M. stebbingi and 1.2 and 1.1 for P. stylifera, respectively. The asymptotic carapace length (CL∞) of female and male was 44mm and 31mm for P. merguiensis, 36mm and 31mm for M. affinis, 28mm and 18.5mm for M. stebbingi and 27.5mm and 18.5mm for P. stylifera, respectively. The mortality parameters of male and female shrimps were different in range including 2.36 – 4.54 for total mortality, about, 2.12–1.83 for natural mortality and 0.24–2.50 for fishing mortality. Total mortality rate for M. affinis and M. stebbingi showed that this rate for males was higher than females. Conversely, total mortality rate for F. merguiensis and P. stylifera was higher for females than males. Exploitation rate for all species was higher in females than that for males. In this study, the highest estimated biomass was found in Kiddy and Jinga shrimps and the lowest biomass was found in Indian white shrimp. The peak of biomass and CPUE was obtained during July-August.
S.a. Hashemi , R. Ghorbani , F. Kaymaram, S.a. Hossini , G. Eskandari, A. Hedayati,
Volume 23, Issue 3 (10-2014)
Abstract
Some biological aspects of Mesopotamichthys sharpeyi were studied in Shadegan Wetland, Iran. Monthly samples were collected from five stations: Doragh, Rogabe, Khorosy, Salmane and Atish. A total of 437 specimens were measured from April 2013 to March 2014. Mean (±SD) (Range) length values for the male and female were calculated as 252±28 (95-357), 249±38 (115-374)mm respectively and mean (±SD) (Range) weight values were 218±31 (18-366 ),239±39(15-651)g respectively. The length-weight relationships were calculated as W=0.000006L3.11 (R2=0.85) for male, W=0.000005L3.14 (R2= 0.86) for female. The spawning occurred from April to July, and length at maturity (LM), weight at maturity (WM) and production per biomass (P/B) were calculated for male and female as LM=208, 220 mm WM=97, 133 g and P/B= 0.53, 0.50 per year, respectively. *Corresponding author
B.m. Gharanjik , Bahareh Nazari, B. Saeedpour, T. Valinassab,
Volume 25, Issue 3 (10-2016)
Abstract
This study was carried out to determine the Seaweed biomass in the coast of Sistan & Baluchestan Province. Beris, Chabahar, Pozm and Tang were introduces as high density zones and Jood & Lipar were selected as low density zones.
From 354.2 km of investigated coastal area, among this, 18.2 km were high density zone and 281.5 km were low density zone. Three transects were fixed in studies area and sampling randomly were done monthly. The samples were measured in area after being cleaned, and separating. During this research, 9 genus were collected. Among these seaweeds, 2 genus were green algea (composed of 2 families and 2 orders), 6 genera of brown algae (composed of 3 families and 3 orders) and 1 genus of red algae.
Wet biomass of Sargassum genus in the total area of Sistan & Baluchestan coasts was 445.9 tons in 2012. Among this biomas, 269.1 tons (%60.35) was found in high density area and 176.8 tons (%39.65) in low density zone. The maximum biomass was obtained 270.4 tons (high density zone: 155.5 and low density zone: 114.9 tons) in Dec. and the lowest biomass was obtained 3.5 tons in March.
F. Parafkandeh, M.a. Afraei Bandpei , A. Solaimani Rudy ,
Volume 25, Issue 3 (10-2016)
Abstract
The study is part of a research project on the southern shores of the Caspian Sea (Mazandaran waters- Kelarabad) was conducted in 2012. The aim of this study was to evaluate the effects of fish farming in cages on the distribution, abundance and biomass of macrobenthos organisms in the water at a depth of 20 meters Kelarabad. Sampling was monthly at three stations including 1(seating cage), 2 (control with a distance of 500 m) and 3 (50 meters after the cage) using a grab with 30 cm diameter. A total of 6 groups of benthic organisms, including 2 branches, 2classes, 4 families and 6 species were identified. Overall, 23442 specimens of large benthic organisms were counted, the lowest and highest frequency at stations 1 (23.4%) and 2 (46.8%), respectively. The results showed that the highest abundance at station 2 with an average of 646.00±1230.43 N/m2 and biomass with 0.526±1.00 g/m2 in station 3, in which can be due to the lack of cage fish farming activity and the presence of big species to depend Cerastoderma lamarki, respectively. The highest abundance and biomass was in autumn with mean 888.3±1371.58 N/m2 and 0.524±0.887 g/m2 and lowest was in winter with mean 143.33±138.22 N/m2 and 0.070±0.078 g/m2. This could be related to activity fish cage culture and wintering season. The Streblospio gynobranchiata of polychaeta dominant benthic organisms with large population accounted 93.3%. This could be due to exotic species, high power compatibility and suitability related to environmental conditions. The conclusion is that the abundance and biomass of macrobenthos organisms in station 1 was less than other stations in which can be duo to concerned fish cage activity and its effects on organisms’ infauna. Therefore, it is suggested that any activity in the Caspian Sea offshore aquaculture should maintain environmental considerations and implementation of detailed environmental impact assessment (EIA) projects.
M.a. Afraei Bandpei, A. Hashemian, F. Parafkandeh,
Volume 25, Issue 5 (3-2017)
Abstract
This research in line with fish cage culture plan in the southern coast of the Caspian Sea was carried out. Sampling was seasonally in 8 transects at the depth of 5-100 m from Astara to Torkaman areas in 2008-2009. The aim of this study was to investigate the distribution, abundance and biomass of macrobenthic invertebrate. The highest abundance and biomass were found in transects of Amirabad with average 10931.7±7301.4N/m2 and Astara with mean 86.2±160.3g/m2, respectively. This could be due to the presence of alien species into the Caspian Sea, Streblospio gynobranchiata in 2003 and is the dominant population of macrobenthic invertebrate concern up to 58.4% and increased of S. gynobranchiata (high power compatibility) and mussels of Cerastoderma glaucum (large size) is relevant, respectively. The abundance and biomass have fluctuations in different seasons and the highest abundance with average 6280.1±5693.1N/m2 and biomass with mean 66.1±126.9g/m2 was in winter and spring, respectively. A significant difference between abundance and transects (p<0.05), no significant difference between abundance and depth and seasons (p>0.05), significant difference between biomass and depth (p<0.05) and no significant difference between biomass at transect and seasons (p>0.05) were found. Also, according to multivariate analysis of benthic invertebrate on the abundance at various depths revealed that depths of 5, 10 and 20 meters from the importance of certain fisheries in terms of frequency, abundance and biomass of the macrobenthic invertebrate, slope substrate, substrate, close to the beach, the accumulation of nutrients, Nursery ground, feeding ground and Spawning ground is important for different important species in the Caspian Sea. Therefore, the establishment of fish cage culture was recommended more than 20-meter depths according to the plans of fish cage culture in the southern coast of the Caspian Sea of the Iranian Fisheries Organization.
R. Abbaspour Naderi, S.y. Paighambari, T. Valinassab, R. Gorbani,
Volume 26, Issue 4 (11-2017)
Abstract
Biomass, Catch per Unit of Area (CPUA), distribution and catch composition of Bottom Trawl demersal resources from Oman Sea (Sistan and Balochestan province coastal waters) were investigated in this study. Data were collected in one research cruise by using R/V Ferdows-1 during 2016. The study area was stratified into 5 strata (M to Q) and 4 Substratum covering the depths of 10- 20, 20-30, 30-50 and 50-100 m in the Oman Sea. A total of 92 stations were selected in a random stratified design distributed in different depths and area. The swept are method was used to access and estimate the amount of biomass and CPUA. Result indicated that the percentage of density of demersal resources in the M Stratum (Biahi to Galak estuary) and Stratum Q (Bersi to Gwatr) had the highest value of biomass and CPUA. Also depths of 10-20 m had lowest value CPUA and biomass of commercial, non-commercial and total species. The amount of biomass in depth of 50-100 m was 4.1 times higher than that of depth 10-20m. Maximum CPUA of commercial, non-commercial and total species was estimated in strata M, M and Q and M respectively. Aroun100 species were identified in this study; the results of the study suggest that high density of commercial species distribution concentrated in West-coast, while non-commercial resources observed in East coast of Sistan and Balochestan province. The Result of this study is beneficial for objective management of Demersal Resources exploitation in Oman Sea.
F. Mehrabi, A. Jafarpour, Gh. Nematzadeh,
Volume 27, Issue 1 (5-2018)
Abstract
Carbon and nitrogen sources are considering as the essential substances for microalgae growth. In this study the effects of sodium Nitrate (NaNO3) and sodium bicarbonate (NaHCO3) on the growth rate of N. oleoabundans microalgae in BBM culture medium were investigated. In this regards, different concentrations of NaNO3 as 0, 0.5. 1.0, 2.5, 5 and 10 and NaHCO3 as 0, 0.25, 0.5, 0.75, 1.0 and 1.25 in BBM during 21 days were tested. According to the results, by application of 10 mM NaNO3 the highest number of microalgae as (84.66±0.577)× 106 cells/mL was recorded and in case of nitrogen absence no increase in cell numbers was observed (p <0.05). However, by increasing of the concentration of NaNO3, the lipid production was decreased which the highest amount of lipid was recorded as 1.32±0.27 gL-1 without nitrogen addition (p <0.05). In case of NaHCO3, by addition of 1.25 gL-1 sodium bicarbonate the highest cell number as (96±1.00)× 106 cell/mL was recorded whereas in its absence the lowest number of (2.00±0.00)× 106 cell/mL was obtained (p <0.05). Similarly, by addition of higher amounts of NaHCo3, the lipid production was decreased as its highest amount as 0.3±0.144 gL-1 was produced at level of 0.25 gL-1 of NaHCO3 (p <0.05). Considering the positive effects of NaHCO3 on growth of N. oleoabundans on BBM, it is recommended to use it for mass production of this microalgae.
R. Tatar, R. Ghorbani, S. Gorgin, Gh. Bandani, M. Yahyaei,
Volume 27, Issue 4 (10-2018)
Abstract
Caspian roach (Rutilus caspius), is one of the most important commercial species in the Caspian Sea with a high level of catch fluctuations over the past decades mainly due to overfishing. In this study, data from 246 specimens caught from beach seine cooperative companies in the southeast coast of the Caspian Sea during the October 2014- April 2015 were analyzed. Results showed that the fish age were ranged between 3 to 10 years with fork lengths and weights ranging 14.5-32.1 cm and 70.7-437 g, respectively. The growth parameters of the von Bertalanffy equation were found as Lt=41.8 [1-e–0.12(t+0.766)]. The length-weight relationships were estimated to be WT= 0.0208 FL2.9184 (R2 =0.901) for females and WT= 0.0138 FL3.0244 (R2 =0.921) for males. Weight increased isometrical with the fork length for females and males. Total mortality, natural and fishing coefficients (Z, M, F) and exploitation rate (E) were estimated to be 1.239, 0.324, 0.916 year-1 and 0.74, respectively. Fish biomass and maximum sustainable yield (MSY) were equal to 417 Kg and 215 Kg, while the ration of cooperative companies catch was 28 Kg. Therefore, it is suggested that the Caspian roach stocks are severely exposed to overfishing, and there is an urgent need to efficient management for stock conversation.
M. Gorgij, M. Yahyavi, K. Rouhani, A.r. Salarzadeh,
Volume 27, Issue 6 (3-2019)
Abstract
Nitrogen is known to have a strong influence on the metabolism of lipids and protein in various microalgae. In the present study, the production of S. platensis was optimized in terms of biomass and protein by using different Nitrogen sources as NH4Cl, NH4NO3 and Urea. S. platensis was grown in Zarrouk’s medium in a 3000 ml Erlenmeyer flask, in which the NaNO3 was replaced by NH4Cl, NH4NO3 and Urea with concentrations of 0.010, 0.025 and 0.050 M. Cultures were incubated at temperature of 30oC, salinity of 25 ppt and initial pH of 9.5 under 12/12 hour light-dark photo period with normal white light. The results clearly showed that S. platensis successfully cultivated by using different Nitrogen regimes, and though the maximum biomass was produced in medium containing NH4NO3, but there is not significant differences between treatments (p>0.05). The maximum protein content was obtained in culture containing NH4NO3 followed by NH4Cl and KNO3, and there is not significant differences between treatments (p>0.05). Moreover, in all S. platensis cultures, increasing in nitrogen concentrations, led to an increase in maximum biomass and protein content. The chl. content increased with increasing Nitrogen concentrations in all treatments and relatively high values (9.18 µg/ml) were found with KNO3 as a Nitrogen source at 14th day of culturing period. Overall, though the results of present study clearly showed no significant differences between treatments, but using of NH4NO3 could have relatively more effectiveness than the other Nitrogen sources.
M.a. Afraei Bandpei, H. Nasrolahzadeh, G. Salarvand , M. Naderi, A. Roohi ,
Volume 28, Issue 3 (9-2019)
Abstract
This study was carried out in line with the Caspian Sea water transportation program to the central plateau on the Southeast shores of the Caspian Sea (Goharbaran region) since 2013-2014. Sampling was performed monthly and there were 8 stations at depths of 5, 10 and 15 meters in 2 transects. The purpose of this study was to investigate the relationships between some physico-chemical parameters of water and total organic matter, distribution, abundance and biomass of Streblospio gynobranchiata (Spionoidae) in the different depths. The results showed that the highest abundance and biomass were in the Eastern transect with mean 1437.1±269.17 ind.m-2 and 0.711±0.131 g.m-2, respectively. A positive correlation was found between the abundance and biomass of S. gynobranchiata with TOM and at 0.01 level, salinity and water temperature at 0.05 level based on Pearson correlation test. The abundance and biomass of S. gynobranchiatain different seasons was fluctuating, with the highest abundance 1550.08±185.22 ind.m-2 and 0.775±0.09 g.m-2 recorded in winter and in January, respectively .So there was a significant difference between the abundance and biomass in different months (p<0.05). This could be due to the approach to the period of water disruption following the seasonal changes and the creation of a bioturbation in the seabed and a deposit feeder species.
Gh.r. Daryanabard, H. Fazli, S.a. Taghavi Motlagh, Gh.a. Bandani, A. Poorgholami Moghadam,
Volume 28, Issue 4 (11-2019)
Abstract
This study was conducted to determination length and age composition, growth and mortality parameters and estimate biomass of Kutum in the Iranian coastal waters of the Caspian Sea from 2017 to 2018. The biometrics data were collected from the fishing cooperatives in the Guilan, Mazandaran and Golestan provinces. The mean (± SD) of fork length and total weight were obtained 37.4±6.9 cm and 729.8±418.4 gr respectively. The range of age was from 2 to 11 year and fish with 3 to 4 years comprised up to 73.4 percent. The mean (± SD) of fork length for 3 and 4 age groups were 33.8±5.8 and 39.0±6.2 cm respectively. In length – weight relationship a, b and r2 were calculated 0.012, 2.99 and 0.96. K value, L∞ and t0 were calculated 0.21 (/year), 61.4 cm and -0.54 respectively. Mortality parameters such as Z, M and F were calculated 0.76, 0.36 and 0.36 respectively. The biomass of kutum estimated 27437.7 tons.
Masoumeh Shams Kahrizsangi, Foaad Albodviraj, Sadroddin Ghaemmaghami, Abolghasem Roohi,
Volume 29, Issue 1 (3-2020)
Abstract
This research was conducted to evaluate the effect of ecological factors on diversity and density of phytoplankton in Caspian Sea. Sampling was carried out from 5 stations included of Ramsar, Nowshar, Noor, Fereydunkenar and Miankaleh (Amirabad) regions (surface, 3 and 5 m depths) from 2016 to 2017. The totals of 56 species belong to 5 phyla of algae division were identified which maximum density and biomass were observed in Skletonema costatum, Thalassionema nitzschioides, Nitzschia acicularis, Pseudonitzschia seriata and Melosira moniliformis. Density and biomass of phytoplankton showed that the mean of biomass was 12.3±2.7×106 cell/m3 and 35.6±7.7 mg/m3, respectively, with the highest average density in winter (19.1±4.4 ind.m-3). The highest and lowest Shannon index was 1.97 and 1.84 in different seasons respectively. Silica, temperature and inorganic nitrogen play an important role in density of algae especially diatoma, cyanophyta and pyrrophyta. The recent study showed that a high N:P ratio in winter and characteristics along with a suitable strategy for Chlorophyta species are important and desirable reasons for increasing their populations.
Mohammad Ali Afraei Bandpei, Gholamreza Salarvand, Hassan Nasrolahzade Saravi, Matin Shakori, Mehdi Naderi, Abolghasem Roohi, Reza Daryanabard, Fariba Vahedi, Iraj Rajabi,
Volume 30, Issue 1 (4-2021)
Abstract
This study was carried out in line with the Caspian Sea Central Plateau Water Transmission Program in the southern shores of the Caspian Sea and Goharbaran region in 2013-2014. Sampling was carried out monthly at 8 stations at depths of 5, 10 and 15 meters in 2 transects. The purpose of this study was to investigate the relationships between some physico-chemical parameters of water and TOM (total organic matter), distribution, abundance and biomass of different species of Amphipoda in half-lines, depths, stations and seasons. Overall, one species of Niphargoides caspius from the Gammaridae and four species of Stenogammarus similis, Stenogammaus macrorus, Stenogammarus carausuii and Stenogammarus compenus of Pontogammaridae were identified. A total of 15118 individuals of the benthic organisms were counted, in which, S. compresus and N. caspius with 68 and 2 percentages, respectively. Overall, the mean (± standard error) density and biomass of benthic organisms during the period were 128±14.08 ind.m-2 and 0.15±0.01 g.m-2, respectively. According to Spearman test, density of S. carausuii, S. macrorus and S. similis was significantly correlated with sedimentation (sand) (p<0.01). Multivariate cluster analysis based on Spearman's correlation coefficient on the relationship between density and biomass of different species of Amphipoda with some environmental parameters, grain size and total organic matter (TOM) of bed sediments showed that the members of this group belonged to a sand bed and dissolved oxygen are more strongly correlated in which could be due to ecological origin of Amphipoda groups.
Matin Shakoori, Mohamad Ali Afraie Bandpei, Hasan Nasrollahzadeh Saravi, Meisam Erfani, Iraj Rajabi,
Volume 30, Issue 4 (11-2021)
Abstract
Feridun Mohebbi, Masoud Seidgar, Mahmoud Hafezieh, Bayramali Dadashpour, Zhaleh Alizadeh Osaloo,
Volume 31, Issue 5 (12-2022)
Abstract
This study investigates the Artemia biomass and cysts changes in Urmia Lake in different time periods. However, changes in Artemia population in other hypersaline lakes such as the Great Salt Lake of America, Dead Sea and Griessmeir lake in Newzeland have also been investigated. The first documented estimation of Artemia stock in Lake Urmia was made by Gϋnther about 125 years ago. After him, in various time periods, Urmia Lake Artemia population was assessed by different authors. The most important researches of them were the studies which performed in last three decades. The highest Artemia population in Lake Urmia has been reported in 1990s which was simultaneous with the highest water standing level of the lake. Here after the lake water level was steadily declined, which negatively affected Artemia communities. In 2010s, Lake Urmia was faced with a water shortage crisis so, Artemia population declined dramatically. Regarding the Great Salt Lake similarities to Urmia Lake, this lake investigation were highlighted in our research. Generally, Artemia cysts density in Urmia lake were decreased from 2500 per liter in 1990s to 4.6 in 2010s, and the biomass from 1500 per cubic meter in 1990s to 4 per cubic meter in 2010s. Lowering the lake water level and simultaneously increasing its salinity is recognized as one of the most important factors in the Artemia population drop. Another crucial parameter in Artemia population decline in Lake Urmia is the significant reduction of algae population, particularly Dunaliella, which is the main food source of Artemia.
Hooshang Ansari, Tooraj Valinassab, G.r. Daryanabard, N. Shiry,
Volume 32, Issue 3 (9-2023)
Abstract
Three research cruises were carried out using Ferdous 1 research vessel equipped with a bottom trawl net in the waters of Khuzestan province during 2018-2021 (except for 2020) to monitor the aquatic demersal resources of the northwestern waters of the Persian Gulf. During this three years’ survey, a total of 51 stations were randomly selected for sampling at 10-50 m depths for further Biomass and Catch Per Unit of Area (CPUA) estimation by Swept Area Method. Four important and commercial species including silver pomfret (Pampus argenteus), tiger-tooth croaker (Otolithes ruber), Sobaity seabream (Sparidentex hasta) and orange-spotted grouper (Epinephelus coioides) were selected. The estimated biomass for years 2018, 2019 and 2020 were 1.1,0.0 and 7.1 tons for silver pomfret; 46.8, 23.3 and 57.6 tons for tiger-tooth croaker; 59.8, 76.7 and 137.3 tons for sobaity seabream and 30.3, 3.1 and 0.0 tons for orange-spotted grouper, respectively. During this period, silver pomfret with 0.01% (in 2018), Sobaity seabream with 3.37% (in 2021) had the minimum and maximum ratio of total biomass, respectively. From point of fisheries management, the following recommendations are proposed:
- Prevent any increase in catch per unit of effort (such as number of fishing vessels)
- Control and supervise the fishing activities, fishing grounds and prohibit the illegal fishing
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