mohammad gholizadeh

The study was conducted to determine the allometry variability of mosquitofish based on 10987 specimens collected from 11 localities in thesouthern Caspian Sea basin in summer 2021. The estimated b-values range from 2.414 for males from thecoastal lagoon of Gorgan Bay to 3.911 for the population from theSorkhroud River. In the basin, theoverall mean of the b coefficient was 3.190±0.413. Thegrowth patterns of most considered groups were positive allometric. The form factor a3.0indicated that body shapes were different between the areas

Liposarcoma, a malignant tumor originating from fat cells, is a rare occurrence in the retroperitoneal region. Surgical resection is the standard method for treating this cancer. This type of tumor is classified into common subtypes, which include well-differentiated liposarcoma and dedifferentiated liposarcoma.
A 53-year-old male patient presented with lower left quadrant (LLQ) pain and melena for two weeks. Further diagnostic evaluation, including colonoscopy, revealed a 50 mm polyp in the hepatic flexure or distal of the ascending colon. The pathological assessment of the mass demonstrated a lipomatous lesion with a nuclear atypical lipomatous tumor, which was diagnosed as well-differentiated liposarcoma. The patient underwent surgical treatment and was discharged following his recovery. Liposarcoma, a malignant tumor originating from fat cells, is a rare occurrence in the retroperitoneal region. Surgical resection is the standard method for treating this cancer. This type of tumor is classified into common subtypes, which include well-differentiated liposarcoma and dedifferentiated liposarcoma. A 53-year-old male patient presented with lower left quadrant (LLQ) pain and melena for two weeks. Further diagnostic evaluation, including colonoscopy, revealed a 50 mm polyp in the hepatic flexure or distal of the ascending colon. The pathological assessment of the mass demonstrated a lipomatous lesion with a nuclear atypical lipomatous tumor, which was diagnosed as well-differentiated liposarcoma. The patient underwent surgical treatment and was discharged following his recovery.

Studies on the load of heavy metals in various mammalian species in most aquatic ecosystems around the world are constantly being conducted. Investigating the concentration of heavy metals in marine organisms is important and necessary for monitoring and assessing the risks of these types of pollutants in marine ecosystems. These studies have confirmed the occurrence of these types of pollutants in top predators of the food chain such as seals. In the present study, 15 Caspian seal carcasses were examined along the Iranian coastline (Golestan, Mazandaran, and Gilan provinces) during 2021-2023. Liver, kidney, and blubber tissues were sampled for heavy metal analysis, and the samples were injected into an inductively coupled plasma mass spectrometer after preparation. The results showed that the highest arsenic concentration in liver tissue was 0.78 (mg/kg) in Gilan province. The highest levels of this element in kidney and blubber tissues were also observed in Gilan province at 1.03 and 3.99 (mg/kg) respectively, differing significantly from Golestan province (P≤0.05). The highest cadmium level was found in liver tissue in Golestan province at 0.4 (mg/kg) and in kidney tissue in Gilan province at 16.28 (mg/kg). Iron had the highest concentration among the other elements, with the maximum levels in liver, kidney and blubber tissues observed in Gilan province at 928.1, 678.9 and 81.37 (mg/kg) respectively. The highest significant level of mercury was found in liver tissue in Golestan province at 5.3 (mg/kg). Lead was also highest in liver, kidney and blubber tissues from Gilan province. Based on the results, it seems that the main sources of environmental pollution in the Caspian Sea can have significant adverse effects on the natural habitats and animal species of this unique aquatic ecosystem. Comparing the results of the present study with those of previous ones can be very effective in the continuous monitoring and surveillance of pollutants, including heavy metals, in the Caspian Sea ecosystem.

To investigate the relationship between the length and weight of Neogobius melanostomus, 5145 fish were captured using nets from March to February 2018. The maximum total length and weight for females were recorded at 12.2 cm and 28.08 grams, while for males, the maximum total length and weight were 11.3 cm and 33.17 grams, respectively. The length-weight relationship for both female and male populations of N. melanostomus in Gorgan Bay across the four seasons (spring, summer, autumn, and winter) showed a high coefficient of determination. The regression slope values (b) for this species in different seasons were significantly different from the isometric growth coefficient of 3 (p < 0.05). Specifically, the t-values were 3.73 for the winter population, 10.80 for the autumn population, 21.25 for the summer population, and 21.71 for the spring population, indicating positive allometric growth throughout the year. The Pauli test confirmed this growth pattern in the N. melanostomus population of Gorgan Bay. Seasonal condition coefficients showed that females had the highest values in summer and winter, while males displayed the highest values in winter.

This study examines the characteristic of microplastics (MPs) in sediments collected from the coastal areas of the southern Caspian Sea, Mazandaran province (Babolsar and Sari cities). Twelve sites for sediment sampling selected during 2022. MPs identification detected primarily under stereomicroscope and then ascertains and discovers their polymer composition by ATR-FTIR. The results showed that Babolsar areas, with 5 meters far from the shoreline, had the most abundance (660±165.15items/Kg). On the other hand, Sari station with 500 meters far from the shoreline contained the least MPs (220±81.33). Average number of detected MPs in all samples was 406.66±161.33. Fibers (80.33%) were the most abundant MPs, whereas films (3.28%) detected the least. In the case of size, the range of 1000-3000µm showed the most abundant MPs (39.34%) and MPs less than 2 µm the least ones (4.10%). Gray and black (50.82%) was the dominant color and yellow (3.28%) was rarely detected color (3.28%). Polymer constituent of examined MPs includes: (PET: 30%); (PS: 20%); (PA: 20%); and (PP: 15%). The findings of this study revealed that MPs occurrence in coastal sediments distribute from several sources; including tourism as well as wastewaters and packaging. These activities cause entering plastic litters along the coastal areas and their degradation accelerated t MPs distribution.

In this study, age and growth of Golden Grey Mullet (C. auratus) was investigated during the years 1394-1397 in the coastal waters of Golestan province. This study was the first study on the modeling and implementation of three models for estimating growth parameters of golden mullet (C. auratus) in Iranian waters (Golestan province). During the sampling period, commercial fishing with a size of 27-33 springs was used, and outside of the fishing season, a net with a size of 20 and 30 was used. Biometry of fish was done including fork length with an accuracy of 1 mm, total weight with an accuracy of 1 gram. The length range for golden mullet was 15 to 59.5 cm and the weight range was 52.5 to 1401 grams. The exponential relationship of fork length and total weight (W=0.69L0023) was obtained. Based on the multi-model approach, the best model to show the growth of this fish was the Gumpertz growth model (∆AIC = 1.71, AIC = 46.13), and the logistic model was the best model to depict the growth of this fish according to the AIC information coefficient ( ∆AIC = 1.27, AIC = 50.71). Considering the pressure of legal and illegal fishing on this valuable species, it shows that the population and the amount of fishing in the south-eastern coast of the Caspian Sea are increasing. The results of this study can be used as basic information for catching and exploiting this species in the future.

Rivers efficiently transfer microplastics into seas, meanwhile they can be temporarily stored in sediments, where they undergo further fragmentation due to biological and physical processes. This study was conducted with the aim of investigating the distribution and abundance of microplastics (MPs) in the surface sediments of Khormarud River, Golestan province, Iran. A total of 15 sediment samples (5 stations with 3 replicates) were taken in the spring of 2022 and the identification of MP was studied using a stereomicroscope. Their polymer compositions were characterized using weak total reflectance Fourier transform infrared spectrometer. The results showed that station 5, with high human activities, had the highest frequency of MPs with 880±160 particle/kg of dry sediments, and station 1, upstream of the river, had the lowest frequency with 200±66 particle/kg. The average of MPs observed in all studied stations was 430.17 ± 92.8 particles. The most abundant MPs were fiber (77.52%) and the least abundant were films (3.10%). The results showed that the 500-1000 µm group had the highest frequency with 44.19%, while the 3000-5000 µm group had the lowest frequency with 3.88%. Black color was the most frequent with 55.81% and blue color was the least frequent with 2.33%. The polymer composition of MPs includes polypropylene (PP, 41%), polyethylene (PE, 30%), polystyrene (PS, 16%), polyester (PS, 11%), and polyamide (PA, 2%). The results of this study showed that MPs in coastal sediments have a complex source that is mostly derived from tourism, sewage, and packaging.

The Environmental variables are considered as important factors determining habitat preference and selection by fishes in the aquatic ecosystem. Therefore, it seems essential to know the habitat requirements of inhabiting species. This study in summer on Kesilian River, one of the considerable sub-basins of the Talar River in the north of country, was selected to investigate the habitat preferences of Kora Barbel (Barbus lacerta) at various ages. According to the diverse habitat characteristics, three sites were selected on the stream, and then samplings were carried out at 211 points using an electroshocker. At each point, environmental parameters including speed, depth, and type of biotic and abiotic substrate were measured and determined. The results showed that this species has different habitat preferences at different ages. General preferences of this species took place in the speed range of 15-76 cm/s and the depth of 45-75 cm. Preference for abiotic and biotic parameters of substrates included "block", "cubble" and coarse and fine particulates organic matter, wood and living parts of terrestrial plants, respectively. Regression logistic indicated that the variables including velocity and abiotic parameters of substrate are the most important factors in presence of this species in the stream. In general, the diverse environmental conditions of the stream have provided different habitat preferences for this species at different ages.

The present study aimed to investigate variability in growth pattern and evaluate abundance of A. persicus based on catch data in the southern Caspian Sea water in a period of 27 years (1991-2018). The data of 72704 specimens were analyzed separately by sex (male, female and population), time (years) and region (coastal waters of Gilan, Mazandaran and Golestan provinces). The highest catch of this species was recorded in 1991 (6038 pieces of the fish) and the lowest catch was recorded in 2018 (292 pieces). During the period, the Golestan province had the highest number of catches (30851 pieces) and Gilan province had the lowest ones (11129 pieces). The maximum recorded fork length of this species was 240 cm in 2006. The results showed that the highest annual average fork length was 151 cm in 2007 and 2010 and the highest annual average total weight in 1993, 1994, 1996, 1997 and 2007, which was 26000 grams. The lowest annual average fork length was 139 cm in 2018 and the lowest annual average total weight was 600 grams in 2010 and 2012. The highest length frequency corresponded for the ranges of 136-148 and 148-160 cm in males and females, respectively. The females showed the highest catches in 1991, and the lowest in 2018, while the males had the highest in 1991, and the lowest in 2014. The females dominated the population in the period of 1991- 2013, and after that this ratio was reversed. The allometric coefficient of growth (b) varied between 1.03 and 3.49 in the study period. The growth pattern was mostly positive allometric in first decade of study (1991-2001), isometric or negative allometric in the second decade of study period (2001-2011), and negative in third decade (2011-2018). During the study period, the condition factor of the fish varied between 0.61 and 0.80, and the average of the factor for the whole period of study was 0.72. Generally, the catch of A. persicus in the southern Caspian waters decreased more than 95% from 1991 to 2018 (a period of 27 catch-years).

Tonsillectomy and adenotonsillectomy are simple surgical procedures that can cause laryngospasm as complications which blocks airflow causing serious issues. The laryngospasm incidence decreases in patients undergoing deep extubation. Present study aimed to compare laryngospasm in innovative method of head down deep extubation with No Touch method.

Forty-two patients were enrolled in the study in (23 females and 19 males) between the ages of 5 up to 15 who were referred for tonsillectomy or adenotonsillectomy. The patients were divided into two randomized No Touch (n=21) and head down deep extubation (n=21) intervention groups according to permuted block randomization. All patients received standard general anesthesia. The first group received the no-touch extubation and the second group received head down deep extubation method. The duration of surgery, Time interval between the injection of reverse drugs and the return of spontaneous breathing (TRDRSB), time interval between anesthesia drug withdrawal and extubation (TIDWE), SPO2, incidence of laryngospasm, and cough were recorded and graded according to their severity at 0, 5, 10, 15 minutes and 2 hours after extubation, respectfully.

The age, weight, gender and duration of surgery, TRDRSB was not statistically different between the two groups but TIDWE showed a significant difference between groups (P<0.001). The SPO2 levels in 0, 5, 10, 15 minutes, and 2 hours after surgery were not significantly different between the “no touch” and “head down deep extubation” groups as well as the severity of coughing and laryngospasm. However, the rate of laryngospasm and cough in "No touch" group was higher than " head down deep extubation " group.

HDDE is an innovative technique that it seems in comparison to No Touch method can reduce the incidence of laryngospasm. However, further comprehensive trials are needed to confirm these findings.

Patients undergoing hemodialysis commonly experience discomfort due to the insertion of needles into their arteriovenous fistula. The aim of the study was to compare the effect of EMLA ointment and lidocaine spray, along with the use of rhythmic breathing on the intensity of pain caused by the insertion of needles in the arteriovenous fistula among hemodialysis patients.

Methods & Materials:

 This study was a randomized clinical trial conducted on a total of 80 patients who were referred to Imam Khomeini and Golestan hospitals in Ahvaz in 2022. The numerical pain measurement scale was used as the data collection tool. The participants were selected using the convenience sampling method and then randomly allocated into two groups. In the EMLA ointment group (n=39), a total of 2 grams of EMLA ointment was applied to the target area 60 minutes before the hemodialysis procedure. In the lidocaine spray group with rhythmic breathing (n=41), 2 puffs of lidocaine spray were administered along with rhythmic breathing 5 minutes prior to needle insertion. The pain intensity was then measured and recorded. The collected data was analyzed using descriptive and inferential statistics in SPSS version 20, with a significance level set at 0.05.

The group receiving EMLA ointment and the group receiving lidocaine spray, with rhythmic breathing had mean pain scores of 1.95±1.09 and 2.12±1.10, respectively. Although the mean pain score in the EMLA ointment group was lower than that in the lidocaine spray group with rhythmic breathing, the difference was not statistically significant (P=0.479).

The findings of this study indicate that both EMLA ointment and lidocaine spray, along with the use of rhythmic breathing, have comparable efficacy in reducing pain among hemodialysis patients. Therefore, considering the patient's condition, the utilization of either of these methods is recommended.

Population growth and pollution caused by the discharge of all kinds of urban, industrial, and agricultural sewage, leachate from landfills, and surface water runoff cause an increase in pollution of water sources. The entry of heavy metals into the environment, especially aquatic ecosystems, due to entering the food chain and jeopardizing human health is one of the concerns of society. This study was conducted to determine the level of heavy metals in muscles of Cynoglossus arel and Pomadasys kaakan fishes in Boushehr coastal waters, north of the Persian Gulf.

This descriptive study was conducted on twenty pieces of Cynoglossus arel and twenty pieces of Pomadasys kaakan fishes take place from three coastal stations of Boushehr, north of the Persian Gulf, Iran during spring of 2022. The samples were randomly selected from the fish market. After preparation, bioassay, and digestion of fish muscle by concentrated nitric acid, the concentration of heavy metals including nickel, zinc, copper, lead, and cadmium (µg/g) in the muscle tissue was measured by ICP-OES device. The concentration of heavy metals in the fish muscle tissue for human consumption was compared with international standards (FAO, WHO, FDA, NHMRC, and UKMAFF). According to the method of the US Environmental Protection Agency for fish consumption, daily absorption estimates and heavy metal risk indicators were calculated.

The risk potential index for both species was less than one. The daily and weekly absorption of Cynoglossus arel (zinc > copper > nickel > lead > cadmium) and Pomadasys kaakan (copper > zinc > nickel > lead > cadmium) were determined. The mean concentration of heavy metals nickel, zinc, copper, lead, and cadmium in the muscle tissue of the studied species was determined to be 1.88±0.07, 27.16±8.11, 11.55±4.12, 1.14±0.06, and 0.19±0.03 µg/g, respectively. The highest amounts of studied metals in aquatic animals were zinc > copper > nickel > lead > cadmium. The concentration of metals in the analyzed samples was lower than the international standards.

Regarding toxicity, the concentration of metals in Cynoglossus arel and Pomadasys kaakan was evaluated as acceptable for human consumption. In addition, the amount of risk potential and risk index for non-cancerous diseases in adults and children in fish muscle tissue was less than 1, and the consumption of this fish does not cause any problems for human health.

Patients undergoing bronchoscopy often suffer from pain, coughing, and suffocation. Therefore, lidocaine is prescribed through various methods to induce local anesthesia. This study aimed to compare nebulized lidocaine and intratracheally injected lidocaine in pain and cough reduction during bronchoscopy.

This clinical trial was performed on 96 patients, divided into two groups of intervention (receiving lidocaine via a nebulizer before bronchoscopy) and control (receiving lidocaine through the working channel of bronchoscope). Then, the patients᾽ cough frequency was recorded during the procedure, and the pain level was measured using a numerical rating scale at the end of the procedure. The data were analyzed with SPSS software (version 16) using the chi-square and Fisher's exact tests. Moreover, the linear and Poisson regression tests were applied to analyze the main variables in this study.

There was no significant difference between the two groups regarding demographic characteristics (P>0.05). Moreover, the linear regression test revealed that the intervention (nebulized lidocaine) group had significantly lower pain scores (1.54±0.08) than the control (intratracheally injected lidocaine) group (2.5±0.26) (P=0.013). In addition, the Poisson regression test showed a statistically significant difference between the intervention (35.22±2.93) and control (48.85±5.96) groups in terms of cough frequency (P<0.0001).

This study indicated that nebulized lidocaine has higher efficacy in reducing the patients᾽ pain and cough during bronchoscopy than intratracheally injected lidocaine.

The relationship between spatial patterns of macrobenthic community characteristics and environmental conditions (dissolved oxygen, temperature, salinity, organic matter content and sediment particle size) was studied at 12 stations in Gorgan Bay (South Caspian Sea, Iran), seasonally in 2017. A total of 8803 individuals belonging to 11 families and 11 species were identified. Three species of polychaeta including Streblospio gynobranchiata, Tubificidae and Hediste diversicolor were the most dominant group in terms of abundance, making up 79.3% of all specimens. The highest density (4733 ind m-2) was observed at St. 1 while the lowest (1166 ind m-2) at St. 9. Biotic indices (i.e. AMBI, BOPA and BENTIX) were used to determine the quality of the bay. Gorgan bay is divided into two distinct zones (eastern and western regions) based on MDS analysis and ecological status. Generally, eastern part of the bay revealed the lowest abundance and biodiversity of macrobenthos. Our results suggest the effect of sediment particle size and TOM as significant parameters on distribution of macrobenthic community in Gorgan bay, South Caspian Sea.

Nowadays, plastic pollution is regarded as one of the most threatening environmental pollution. In this regard, microplastics may enter the food web and produce some negative impacts in aquatics. The goal of the present study was to study effects of polystyrene microplastic on antioxidant and immune genes expressions in gold fish (Carasius aurata). For this, polystyrene microplastic was synthetized via suspension and emulsion polymerization method in two sizes of 0/25 and 8 µm. The fish were exposed to the microplastic with sizes of 0.25 and 8 µm and concentrations of 0.05, 0.5 and 5 mg/L during 28 days under 6 treatments. Based on the results, polystyrene microplastic induced gene expression of SOD, CAT and HSP70 that were dependent on the microplastic concentration and size. Smaller size of microplastic showed higher induction effect on the studied genes expressions so that in most cases, the highest level in the same concentrations was observed in the treatments exposed to 0.25 µm microplastic. With increase in microplastic concentration from 0.05 to 5 mg/L, a similar decreasing-increasing trend was observed in the investigated genes expressions but the CAT gene reaction was slightly different. Overall, more studies seem necessary to understand polystyrene microplastic effects on aquatics and its potential mechanisms. With respect to the results from the present study indicating the changes in antioxidant and immune genes expressions under microplastic exposure, establishing some strategies seem to be obligatory to manage the effluents entered to the aquatic ecosystems and prevent more microplastics increase in the environment. Totally, based on the results, it could be said that polystyrene microplastic as a pollutant can induce the antioxidant and immune system of gold fish.

In this study, the trophic status of the Bustan dam reservoir was investigated using Palmer and Carlson indices. Biological parameters including phytoplankton and environmental factors such as phosphate, nitrate and chlorophyll were sampled at the depth of 0.5 meter in five stations in three replicates seasonally in 2019, repetitions and Then the Palmer and Carlson indices were determined. The Palmer index in Bustan dam was estimated as 24, 31, 27.6, and 28.8in spring, summer, autumn, and winter, respectively.  According to the Palmer index classification, in all four seasons, Bustan dam water is in the category of water with high organic matter. The highest value of Palmer's index was obtained in summer (31) and its lowest value was obtained in spring (24). The highest nutritional status of Carlson's index was related to summer (60.46 eutrophication) and the lowest level was found inwinter (52.44 eutrophication), which indicates that the reservoir has moved to semi-nourishing condition in winter season. Also, the highest nutritionism status was observed in station 3 (54/23). According to Palmer's and Carlson's indices and the ratio of phosphate to total nitrogen, the main factor of nutritionism in the reservoir of Bustan dam was phosphorus compounds that enteres the reservoir from external sources of the dam and ultimately causes the decrease of water quality.

In this research accumulation of Aluminum (Al), Vanadium (V), and Tin (Sn) and their health risk assessment due to consumption three fish species include Pickhandle Barracuda (Sphyraena jello), Japanese threadfin bream (Nemipteru japonicus), and King soldier bream (Argyrops spinifer) were investigated. Fish was harvested from Jofre in Bushehr afterward preparation, heavy metals concentration of Al, V and Sn in fish muscle were determinate.  Heavy metals concentration compared with standard of World Health Organization (WHO). Target Hazard Quotients (THQ), estimated daily intake (EDI) and estimated weekly intake (EWI) was determined, and in final Consumption Rate Limit (CRlim) was calculated. According to the results, Al concentration in all of the fish muscle (19.65 to 34.44 μger/ger) was more than standard of WHO. THQ of Al in three fish species and THQ of Sn in King soldier bream in two age category more than 1. EDI of Al in King soldier bream (16.31 μger/day) and Japanese threadfin bream (11.41 μger/day) more than Provisional Tolerable daily intake (PTDI). The highest and lowest of CRlim was related to V in Pickhandle Barracuda for adults (4.65 kg/day) and Al in King soldier bream and Japanese threadfin bream for children (0.0004 kg/day). In conclusion, according to the high accumulation of Al in all of fish species muscle, suggested that in order to prevention from undesirable non-carcinogenic in consumers during the long term, limitation of consumption investigated fish to be planning based on Al concentration.

Benthic macroinvertebrate communities are a biological indicator in aquatic ecosystems. The aim of this study was to investigate the abundance and biodiversity of macroinvertebrate communities in Khormarud River, Golestan Province. Macroinvertebrate samples were collected seasonally from 5 stations with three replications in 2020 using a Vanveen grab with a cover area (225 cm2). A total of 819 specimens of macroinvertebrate belonging to 6 orders and 10 families were identified, with the highest diversity belonging to the order of insects with 7 families and the highest abundance belonging to Chironomidae (31.5%) and then Tubificidae (22.47%). Spring with 45% had the highest and winter with 22% had the lowest abundance. The highest distribution of macroinvertebrate was obtained in station 1 in upstream (40.66%) and the lowest in station 5 in downstream (5.86%). The results showed that the highest Shannon and Simpson diversity indices were obtained in station 1 in upstream of autumn season (1.96 ± 0.32) and (0.85 ± 0.11), respectively. Also, the highest values ​​of Margalf species richness index in station 3 in midstream of winter (2.06 ± 0.4) and Pielou's evenness index in station 3 (0.94 ± 0.19) were spring. According to the Multidimensional Scale Analysis (MDS), the distribution of macroinvertebrate among the stations showed three distinct groups. PCA results showed that organic matter and clay are the most important environmental factors in the changes of macroinvertebrate communities in Khormarud river, Golestan province. The results showed that this river due to increased organic matter from agricultural areas, adjacent urban and rural wastewater caused increased contamination of the benthos resistant to the pollution, including Tubificidae and Chironomidae, these indicators could be used as useful tools for evaluating water supplies quality.

The assessment of human health risk associated with accumulation of lead, copper, zinc, nickel, and Arsenic in the muscle of bartail flathead (Platycephalus indicus) collected from Jofreh pier and Bushehr port, northwest of the Persian Gulf of Iran was examined. A total of 80 P. indicus were collected and analysed using ICP-OES from two seasons (summer and winter) of 2019; estimated daily intake (EDI), estimated weekly intake (EWI), target hazard quotient (THQ), hazard index (HI) and Carcinogenic risk (CR) were determined. The mean concentration (μg/g) range were observed as: zinc (16.37-50.17)> As (5.65-8.83)> Cu (2.19-3.63)> Pb (0.62-6.37)> Ni (0.17-1.08). Hazard index (HI) for adult and children during consumption of P.indicus was <1, the highest HI values were calculated for adults (0.06) in Bushehr and children (0.14) in Jofreh. The CR levels for Ni and Pb were within acceptable limits (10-6 to 10-4) and arsenic was unacceptable (> 10-4) at sampling sites.

The purpose of this study was to investigate the population of benthic invertebrates and their relationship with environmental factors of Gorgan Bay Inlet. The abundance of benthic invertebrates during 2017 in three seasons from 9 stations in three sites, bay mouth, Ashuradeh coast and sturgeon culture area was studied using three replicates (225 cm2). In this study, in total, fauna was identified: 3 phyla, 6 classes, 12 families and 12 Genus. Streblospio gynobranchiata (2347±177, 47%) and Hediste diversicolor (873±101, 17%) had the highest abundance. The highest species abundance was observed in spring and the lowest species abundance in autumn. The lowest Shannon (1.12) and Pielu index (0.62) were obtained in the sturgeon culture area. Also, the dbRDA graph based on DistLM model showed that temperature, salinity and clay temperature variables and sand, silt and dissolved oxygen variables were responsible for causing abundance of fauna among different stations in the sampling seasons. According to these results, it can be concluded that macrobenthos in different seasons and areas have many changes in abundance and diversity index. Therefore, when using these communities to assess the impact of environmental factors, their natural changes should be considered.

Basically, after the conclusion of the contract, which can sometimes be very long, is the stage of implementation and fulfillment of mutual obligations, which arises in the first place from the authorized intention of the parties, which is based on the principle of freedom of contract and is manifested in the contract documents. Although the parties state their claims in the contract documents according to the principle of freedom of contract, these freedoms are subject to legal restrictions. On the other hand, the behavior of the parties to the contract is very important in how to fulfill the mutual obligations contained in the written documents of the contract. But it has not been widely cited in British courts. It should be noted that in all legal systems based on the rule of will of the parties in contracts, the subsequent behavior of the parties is considered the source of interpretation of the contract. Therefore, in Iranian law, despite the lack of specification, it can be accepted that by fulfilling the above conditions, the subsequent behavior of the parties in interpreting the contract can be cited. In the Convention on Sale and International Documents under study, despite the disagreement, it is accepted that the subsequent behavior of the parties can resolve the ambiguities in the contract, and explicitly the subsequent actions and behavior of the parties in interpreting the contract and clearing the ambiguity is considered.

This study was aimed to estimate growth parameters and mortality rate of stickleback caught from the southern Caspian Sea. Fish sampling was conducted from February 2018 until June 2018. To do so, 247 fish were sampled, weighted and biometric assays were done, among which 237 samples were sex-determined. The numbers of male and female fish samples were 106 and 131, respectively. Kolmogrove-Smirnov test showed a significant difference in length-frequency distribution between sexes. Randomization test was applied to compare mean length of male and female samples which indicated a significant difference between sexes. Results indicated that the shortest and the longest fish recorded in the Caspian Sea were 1.55 and 6.93 cm, respectively. Vonbertalanfi Growth factors in the Caspian Sea was obtained (L∞= 8.797 cm, k=0.356 per year and t0= -0.699 year). Mean natural mortality for male, female and total were 1.86 year-1, 1.76 year-1, and 1.64 year-1, respectively. Mean relative weight of the female, male and total fish were 85.2%, 83.02% and 85.16%, respectively, implicating inadequate condition of the fish weight. The present findings help better understanding of biological status of stickleback stock in southeastern part of the Caspian Sea.

The aim of this study was to evaluate the health of Kabudal and Shirabad Streams and Zarrin Gol River in Golestan Province using biological indices (benthic invertebrate community). Aquatic invertebrates are one of the most important and beneficial organisms in biological monitoring. In this study, based on the existing barriers and the possibility of access to the river, 5 stations in Kaboudwal Stream, 3 stations in Shirabad Stream and 10 stations in Zarrin Gol River were determined. In order to sample large benthic invertebrates using a surber sampler with dimensions of 30.5 30 30.5 cm and with 3 replications in each station seasonally in a period of one year (2018-2019) were collected and identified based on reliable identification keys. Then alpha, beta and multivariate biodiversity indices of water quality health assessment were studied. The results of this study showed that the effluent of fish farms had a significant effect on river water quality so that the percentage of pollution-sensitive families in the stations after fish farms decreased and increased the frequency of resistant families. The streams of Golestan province generally experience moderate ecological conditions and move towards poor conditions, which with the increasing trend of destruction of ecosystems along riparian zone and the impact of agricultural and aquaculture activities, it seems that we will have these conditions in the future.

The bony fishes of the Caspian Sea are the species whose reserves are decreasing due to Pollution, habitat destruction, exploitation and illegal fishing. Regarding the extent of illegal fishing in Golestan province and lack of sufficient studies in this regard, this study examines the changes in illegal fishing and identifies the factors involved in its occurrence. Using descriptive-analytical method, designing a questionnaire and questionnaire in person, the factors affecting the incidence of illegal fishing in the southern part of the Caspian Sea, Golestan province, were identified and ranked in two regions of Turkmen and Gomishan. Required information was collected by completing 50 questionnaires and questions related to social, economic and hunting causes during a one-year period (1395) was answered. The results showed a significant difference in illegal fishing between Bandar-Torkman and Gomishan (p ˂0.05, t- test= 3/3). Also, there was a significant difference between the winter and the rest of the seasons in the illegal fishing survey (p ˂0.05, ANOVA= 2/15). Analysis of illegal catch data by using linear regression model showed that there was a significant correlation between the probability of illegal catching of all trapped bones (in kilograms) and independent variables, including information from fish, establishment of trapping in sea, total number of traps, The main motive for hunting and the distance of the sea. This study showed that the rate of catches and reserves of bony species in the Caspian Sea has decreased, which has been accompanied by an increase in illegal fishing activities.

Aquaponic is considered a sustainable semi-closed system for food production that combines aquaculture and hydroponics. The aims of this study were to evaluate the influence of aquaponic on the growth and feed performance, digestive enzyme activity and blood parameters of Common carp juveniles for 60 days. This experiment consisted of three groups (three replications per group) which included; cultivation of common carp without plants (T0), use of aquaponic system for culturing common carp with lettuce (TL) and cucumber (TC). A total of 225 carp (initial body weight: 11.59 ± 0.41g) were randomly distributed in nine 60-L tanks. Results showed that aquaponic system in TL and TC groups could increase the weight gain (WG) and specific growth rate (SGR) and reduce the feed conversion ratio (FCR) of common carp. Total protease, amylase, and lipase activities were also significantly higher in TL and TC groups than control group, respectively. After 60 days, serum lysozyme activity and total immunoglobulin were significantly higher and serum cortisol and glucose levels were lower in aquaponic groups than the control group. The highest serum catalase and superoxide dismutase were observed in TL and TC group. The best effect on growth, digestive enzymes, and immune response were shown in TL and TC groups (Aquaponic system) compared to control.