To estimate the biomass and secondary production of macrobenthos in Khore-e-Mousa creeks, 216 sediment samples were taken. The sampling period started in 1996 and terminated in 1997. A bimonthly sampling strategy was adopted. The samples were taken by Van-Veen grab (0.1 m2) from the beginning, middle and end of each creek (Khor). To estimate the biomass of the macrobenthos, the Crisp method (1984) was employed. The standing crop was expressed as dry weight and ash free dry weight. For the measurement of secondary production, a dominant crustacean species Apseudes sp. was used. The results indicated a low biomass per unit area in Khore-e-Mousa creeks. Maximum and minimum amounts of the standing crop were found to be in June (33.5 g DW/m2) and December (2.19 g DW/m2), respectively. Amongst all creeks, Douragh creek displayed the highest (24.93 g DW/m2) and Beehad the lowest (2.24 g DW/m2) standing crops. During the study period, 1483 individuals of Apseudes sp. were collected and grouped into 5 age classes according to Bhattacharya (Sparre, 1989) method. The secondary production was estimated to be 0.08 g/m2 ash free dry weight (AFDW). The production/biomass ratio (P/B), therefore, is calculated as 0.08÷0.18=0.44. Considering the ecological efficiency, (transfer efficiency) of different trophic levels which is about 10%, the fish production is estimated to be 2430 tons in Khore-e-Mousa area.

This study aimed to identify the effect of environmental conditions on the diversity and abundance of polychaetes in the southern shores of the Caspian Sea in Guilan, Iran. Sampling of seasonal sediments was done (June 2017 - May 2018) in 4 stations and three depths of 1, 5 and 10 m with the help of a Van Veen grab sampler with cross section of 225 cm2 and three replications. Temperature, salinity, pH, dissolved oxygen, suspended solids and organic matter were recorded at each station. A total of 2711 polychaetes belonging to 5 species, 5 genera from 3 families were identified. The highest abundance was related to H. kowalewskii (39%) and the lowest abundance was related to H. invalida species (3%). The mean density in the four seasons of spring, summer, fall and winter was 67.66, 81.25, 48.66, and 28.33 worms per m2, respectively. The highest species diversity was 2.16 species per square meter and the biomass of 62.75 mg/m2 in spring and the lowest was in winter. The highest density, diversity and biomass were 80.41 worms per square meter, 2.33 species per square meter and 70.83 mg/m2 on the shore of Chamkhaleh, respectively; and the lowest were 16.83 worms per square meter, 1.5 species per square meter, and 31.41 mg/m2 on the shore of Chaboksar, respectively. The highest density, diversity and biomass were 127.87 per square meter, 3.68 species per square meter and 107 mg/m2 at a depth of 10 meters, respectively. The correlation results showed that among environmental factors, only organic matter had a direct significant relationship with species diversity. Density had a significant direct relationship with temperature and organic matter. Other factors did not show a significant relationship. The results of stability level of different species in the southern shores of the Caspian Sea (Guilan province) showed that N. diversicolor and H. kowalewskii species exist temporarily and other species randomly.

This study was carried out during two years study from oct. 2005. to sep. 2007 in Bahrekan coastal waters in Northwest of the Persian Gulf. Sampling was done Seasonally from 5 stations (4 stations in artificial reef site and one station in muddy soft bottom area as a control site). Generaly 14 and 74 groups of attached fauna were observed in the first and second year of study respectively, and the most dominant groups were barnacles, anthozoa, spongs, bryozoans, echinodermata, isopoda, polychaets and gastropods. 42 species of decapods crustacean and coelenterate only in reef site and 12 species of mollusk only in control site were observed. 18 species were common between two sites. Biomass variations were observed in different seasons and the highest biomass were found in winter due to barnacle abundance.

During one year survey (January to December 2007), Khouzestan coastal waters in the north west of Persian Gulf were examined to investigate juvenile fishes distribution, density and biomass. Monthly juvenile fish samples were caught using a 360 hp research vessel towing a 24 mm mesh size bottom trawl. Trawling was carried out at 10 randomly selected stations. Distribution map for dominant species was prepared and biomass and CPUA was estimated in the study area. Highest and lowest CPUA was observed in October and December, repectively.Biomass fluctuations showed increasing trend during warm seasons.Significant correlation was recorded between environmental parameters (water temperature and salinity) with biomass and number of species per month in the study area.

Stock assessment and production of fish species was carried out from November 2008 to October 2009 in the Shadegan wetland. Samples were collected from at seven stations، Mahshar، Rogbe، Khorosy، Canal، Ateish، sarakhieh and Abadan road in the Shadegan wetland in Khuzestan provinces. During one year study were measured more than 2000 specimen fish and depletion method was used for fish stock assessment. Maximum and minimum biomass (season) was measurement in Spring (249. 61 kg/ha/year) and winter (157. 90 kg/ha/year) respectively. Maximum and minimum fish biomass (species) and fish production (species) were Cyprinus carpio، Thrssa ilisha and Barbus luteus، Thrssa ilisha respectively. Fish production and biomass in wetland Shadegan were estimated 130. 41 (kg/ha/year) and 197. 7 (kg/ha/year) respectively.

The use of waste water may help sustainable soil fertility via improving the physical, chemical and biological soil characteristics. The main purpose of this study was to determine the effect of industrial wastewaters from three factories, Esfahan Steel Company- Zobahan-, Esfahan Mobarakeh Steel Corporation- Foolad Mobarakeh- and Esfahan Polyacryl Company; in two forms (treated and untreated) on C mineralization, microbial biomass C and metabolic quotient (qCO2). The response of soil microbiological indices such as C mineralization, microbial biomass C and qCO2 to the applications of effluent wastewaters over 112 days of incubation period was evaluated under laboratory conditions. Results showed that the effect of industrial wastewaters on C mineralization was significant and the untreated wastewater from Polyacryl Company increased C mineralization significantly. Other wastewaters decreased C mineralization or did not have a significant effect. Microbial biomass C increased during the first and second month of the incubation period, but during the third month the untreated wastewater from Zobahan, treated and untreated wastewater from Foolad Mobarakeh decreased the amount of soil microbial biomass C. The effect of industrial wastewaters on qCO2 values was substantial and variable. There was a decrease in qCO2 during the first and second month of incubation period. The application of untreated wastewater from Zobahan, treated and untreated wastewaters from Foolad Mobarakeh increased qCO2 during the third month of soil incubation. Briefly, the utilization of wastewaters initially increased C mineralization, microbial biomass C and reduced qCO2, while at the end of the incubation time most wastewaters decreased C mineralization, microbial biomass C and increased qCO2. This might indicate that the labile organic matter contents in wastewaters were reduced and the concentrations of heavy metals in soil were increased during incubation period.

The application of herbicides as organic chemical compounds to control pest and weeds may affect the population and activity of microorganisms, and this may have an influence on biochemical processes that are important for soil fertility and plant growth. The primary objective of this study was to evaluate different loading rates of eradican (EPTC) on soil microbial biomass C and N, microbial biomass C/N ratio and the activities of urease and arylsulphatase under field conditions. In this experiment, loading rates of 6 and 9 L ha-1 eradican were applied to a calcareous soil cultivated with corn (Zea mays L.) and left uncultivated using split-plots arranged in a completely randomized block design with three replications. The experiment was conducted in the Kabootarabad’s Agricultural Research Center, Isfahan. Soil microbial biomass C and N were determined at 30th and 90th days after the onset of experiment and the activities of urease and arylsulphatase were assayed at 30th, 60th and 90th days. Results showed that in soils cultivated with corn microbial biomass C increased with increasing eradican levels; and in both cultivated and uncultivated soils microbial biomass N and microbial biomass C/N ratios were increased over the control. At 30th day, urease activity at 6 L ha-1 level reduced, while at 9 L ha-1 level it increased compared with the control soils. At 60 day, there was no significant difference in the urease activity between the treatments. At 90th day, the activity of urease showed slight fluctuations. There was a reduction in arylsulphatase activity of the cultivated soils by increasing the loading rates of eradican during the experiment, and in uncultivated soils no trend was observed. Briefly, the use of eradican can cause either reduced or increased microbial biomass sizes and enzyme activities in calcareous soils These changes, however, depend largely upon the application rate of eradican, time elapsed since eradican application (i.e., sampling date) and the presence or absence of plant

In this study, we used "Ferdows 1" research vessel and sampling conducted on random basis, through 119 sampling stations in 7 zones with 4 deep-sea layers as: 10-20, 20-30, 30-50 and 50-100 meters, throughout the Oman Sea. Achieved data recorded in pre-schemed forms and processed through "Excel" and "Arc View GIS" soft wares. One hundred species or genus identified in bottom trawl catch composition which categorized as commercial and non-commercial species. The total biomass of aquatics in bottom trawl net estimated as 52472.7 Mt. 60% of this amount allocated to commercial demersal species with 31651.7 Mt. Comparing biomass rates in the Oman Sea layers, it is determined that the maximum biomass rate is in 50-100 and 10-20 meter layers, respectively. Study of CPUA in 7 zones of the Oman Sea revealed that identical to biomass, zone F (Sirik to Jask) positioned first with 20162 Kg per square nautical mile. For 10-20 meter layer, CPUA is 1.6 folded in 50-100 meter depth.

Sampling of banana shrimp stock was occurred for estimating the biomass and distribution purposed by wooden trawler in aquatic habitat from January 2013 to January 2014. Towing operation was done from Sirik (26O 25’ E, 57O 01’ N) to Dargehan in north of Qeshm island (27O 02’ E, 56O 12’ N). Carapace length – total weight relationship for mixed gender was estimated as W= 0.0015L2.7868. Recruitment was occurred all around the year, but maximum was in July to November (63%). Exponential probability of capture was estimated as Pi=1/[1+exp(-0.56(Li-23.78))]. Biomass of banana shrimp was estimated as 1044.1 tone by swept area method and total allowable catch was estimated 835 tone. Maximum biomass of banana shrimp was 507.6 tone (about 48.6%) in depth layer of 5-10 m and the most concentration of the shrimp was belonging to west part of Hormoz Island. Optimum time to starting the catch season, based on the 28 mm (Cl) as optimum length of harvest, was estimated 1st October, 2013. Changes in natural mortality values could be effected the length of catch and optimum time of harvest too. The catchability coefficient, q, was estimated 0.000371 and total biomass was calculated 1232 tone by depletion method. Such difference in estimated biomass from two methods maybe belong to add juvenile to main stock during the catch season or increasing the body mass of each individual in the stock.

In order to study the effect of dextrose and mixed probiotic on growth factors and survival rate of Sward tail larvae, the larvae were fed three diets, including the first group (control diet) with commercial diet (Biomar, 0.4 mm at the rate of 5% of biomass), the second group with commercial diet (at the rate of 5% of biomass) and dextrose (0.4 g/k of commercial food weight) and the third group with mixture of commercial diet (at the rate of 5% of biomass), dextrose and two probiotics, including Bacillus coagulance and B. subtilis (0.4 g/k of commercial food weight). The larvae rearing continued for five weeks. The results showed that survival rate (SR%) and growth factors such as specific growth rate (SGR), body weight index (BWI), percent of the body weight index (PBWI%) and daily growth rate (GR%) and food conversion ratio (FCR) in the third treatment groups was better than others and a significant change were observed between the treatments (P≤0.05). Therefor feeding with probiotic diets, including B. coagulance and B. subtilis, improved the survival rate and growth factors and using it in the diet, is recommended.