مقالات رزومه دکتر حسن فضلی

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.

This research was carried out in order to determine the length and age composition, calculate growth and mortality parameters and calculate the biomass of golden gray mullet in the Iranian waters of the Caspian Sea during the year of 2022-2023. The biometric data were collected from beach seine fishing cooperatives in the Guilan, Mazandaran, and Golestan provinces. The mean (± SD) fork length and total weight were measured at 29.9±4.8 cm and 305.7±143.0 g, respectively. The age range was 2 to 11 years, and more than 74.4% of the age group were 3 to 4 years with the mean (± SD) fork length of 26.3±5.1 and 31.3±5.6 cm, respectively. In the relationship between fork length and total weight, the values of a and b were calculated as 0.018 and 2.836, respectively, with a correlation coefficient of 0.97. Growth parameters, including the von Bertalanffy growth equation constants (K, L∞, and t0), were determined as 0.14 (/year), 64.0 cm, and -1.02, respectively. Mortality parameters, encompassing total mortality (Z), natural mortality (M), and fishing mortality (F), were calculated as 0.95, 0.30, and 0.65, respectively. The biomass of golden gray mullet was determined 12155.5 tons. This research provides valuable information in the direction of sustainable management and protection of golden gray mullet stocks in the Iranian waters of the Caspian Sea.

The aims of the present study were to investigate the macrobenthos communities in the Caspian Sea and to investigate the pollution of this ecosystem based on the pollution indices ABC (Abundance Biomass Comparison), BC (Biotic Coefficient) and ABC curve in 2018 (autumn and winter) and 2019 (spring and summer). According to the results, polychaetes, crustaceans, and bivalvia formed the major groups of macrobenthos communities with 4, 11 and 1 species, respectively. The polychaetes (mainly Streblospio gynobranchiata) included about 70% of the total abundance and the group of bivalvia (Cerastoderma glucaum) included about 76-93% of the macrobenthos in all seasons except in spring. The mean values of the Shannon index and evenness indices were calculated as (1.56) and (0.55), respectively. The annual pollution (ABC) and BC indices were obtained as -3.1 and 2.7, respectively. These values along with characteristics of ABC curve indicate severe stress caused by pollution in the Caspian Sea ecosystem. In this study, the percentage abundance of the invasive species S. gynobranchiata in macrobenthos communities was 52%, which is about 10% decrease compared to 2009 and 2010. This decreasing trend can be considered as positive evidence in the improvement process of the ecosystem in this part of the food chain. However the continuity of recovery trend needs more time, no force by new stressors, proper management, and reduced pollutions into the ecosystem.

The impact of the covid-19 pandemic on job opportunities losing and life quality reduction of the traditional fisherman community of Iran in order to guide the interventions to maintain the employment and provide the livelihood of the fishing communities were studied in 2021 through an online electronic questionnaire. The data collection was done in a simple random way by sending the link of the questionnaire to the fishing community using the WhatsApp social network. The data quantification method was used to describe the results. A total of 693 questionnaires were received, of which 98.6% were men and 1.4% were women. On the other hand, 76.9% of the interviewees were young people under 50 years old. The results showed that 61.3% of the interviewees confirmed that at least one of their family members lost their job, 84.5% stated that their income decreased, and about 83.2% declared that they had lost their jobs for more than a month due to the spread of the Corona virus. Staying at home to avoid being exposed to the disease as the main reason for unemployment was declared by 65.3% of interviewers. Almost 32% of interviewees stated that they have the possibility of finding an alternative job, and among them, free labor jobs with 42.5% and agriculture with 25.8% were the most important alternative ways of generating income. The outbreak of the Covid-19 pandemic has negatively affected the livelihood of the Iranian fishing society, 89.3% of the fishing society was generally worried about preparing food during the Covid-19 pandemic period, and 59.6% were not able to provide their health and medical items. The results of this research recommend the intervention measures of the government regarding the livelihood of the fishing community during unemployment due to crises.

In this study, the biological indicators (length, weight, age) and the stock of the common kilka (Clupeonella caspia) in the Iranian waters of the Caspian Sea were investigated in 2020 and 2021. The results showed that the amount of kilka caught was 20050 tons in 2020, reached 20138 tons in 2021, and presented fairly stable. The catch per unit effort (CPUE) was 2.298 and 2.321 tons per vessel per night, respectively. The average fork length (± standard deviation) of common kilka (male and female) was 100.9 ± 11.1 mm, and the minimum and maximum were 62.5 and 137.5 mm, respectively. In the catch composition, age groups of 3 and 4 years dominated the catch, representing 78.9% and 77.9%, respectively. In the years 2020 and 2021, the total biomass was estimated to be 92653 and 78135.3 tons, age 3 had the highest biomass (31615.1 and 22672.6 tons, respectively). The biomass of mature individuals were 44277.6 and 41606.5, respectively. The ratio of matures to the total biomass was 47.8% and 53.2%, respectively. The acceptable biological catch (ABC) of this species was estimated at 18,000 tons with a precautionary approach. During the last decade, the average catch of this species was 22769 ± 1904 tons, which is more than the estimated ABC.

The restoration program of Caspian kutum (Mahi Sefid) stocks was carried out by the Iranian Fisheries Organization about four decades ago, following its catch reduction in the early of the last century. Despite releasing about 150 million juveniles annually, the catch has always fluctuated and the average catch has never exceeded 10,000 tons. In addition, expected diversity and biomarkers in newly released stocks, such as length and weight, and growth and reproduction indices have also declined. In the present study, the strengths, weaknesses, opportunities and threats of the program for breeding and release of Mahi Sefid in the Iranian waters of the Caspian Sea have been investigated using the SWOT-FAHP method. The results show that although strengths outweigh weaknesses that the biological, social and economic values of Caspian kutum and the existence of specialized hatcheries with the presence of experienced experts are the most important strengths. In contrast, the threat points outweigh opportunities, and in general it can be acknowledged that this situation requires strategies to reduce threats. Therefore, strategies to improve the process of rebuilding Caspian kutum stocks were developed and prioritized by the Quantitative Strategic Planning Matrix (QSPM), which among the identified strategies, contingent (conservative) strategies have the highest score, and accordingly, providing and strengthening breeding infrastructure, especially Natural reproduction in migratory rivers, participation of non-governmental organizations in the protection of local rivers, use of equipment of hatcheries and reconstruction of reserves and updating of worn-out equipment in order to continue the process of artificial reproduction due to pollution and destructive factors in some Rivers, gene bank formation, implementation of breeding program and application of research results on the time frame of fishing and standardization of fishing equipment, scored the most points among contingency strategies.

The COVID-19 pandemic has widely forced universities to provide electronic education, so, it is necessary to examine the quality of this type of education. The aim of this study was to investigate the quality of virtual learning during COVID-19 pandemic from the perspective of dental students in Mazandaran University of Medical Sciences.

A descriptive-analytical cross-sectional study was performed and dental students in Mazandaran University of Medical Sciences who studied via on-line courses in 2020/21 academic year were included. A researcher-made questionnaire was used consisting of five components: implementation method, facilities and technology, content, strategies and methods, and evaluation.

In this study, 128 students completed the questionnaire. According to findings, in first semester, the status of some components, including implementation method, content, strategies and methods, and evaluation were unfavorable, but facilities and technology were found to be relatively favorable. Also, in second semester, the situation of strategies and methods was unfavorable, and the rest of the components had a relatively favorable condition. Female students were more satisfied with the quality of virtual learning.

In general, the quality of virtual learning in Mazandaran School of dentistry was unfavorable in 2020, but became relatively favorable later. Despite improvements in 2021, special attention should be paid to this modern educational method.

Haraz River has an important role in the development of aquaculture and the production of rainbow trout in Mazandaran province. Since 2015, the production of rainbow trout has been decreased in the farms along the river and almost halved. This study have been investigated the microbial indices and heavy metals in water as well as the identification of common bacterial pathogens and their resistance to antibiotics and used them as effective factors in the fish health and production. This study was conducted during four seasons (summer, autumn and winter 2017 and spring 2018) in 6 rainbow trout farms along the Haraz River. The results showed that the amount of the water mercury in all seasons was from minimum 2 to maximum 12 times the allowable limit but the arsenic level was standard in all sampling times. The most important clinical symptoms were observed in the fish including fin rot, erratic swimming, inflammation and hyperemia of the liver and kidneys. From 420 fish with clinical signs, 12.15% and 87.85% of fish were positive and negative bacterial culture respectively. The all of bacterial isolates were gram-negative and no gram-positive bacteria were isolated. The bacterial agents identified were including, Yersinia (37.25%), Aeromonas (33.35%), Eduardzilla (11.76%), Vibrio (7.84%), Pasteurella (5.88%) and Citrobacter (3.92%). The highest and lowest antibiotic resistances were found against amoxicillin and trimethoprim sulfamethoxazole respectively. In evaluation of the microbial water indices including total bacterial count, coliform count, fecal coliform count and E. coli, the results showed that the all of microbial indices were not allowable level in the most of the sampling time.

The main objectives of the present study were to estimate of catch age structure ، biomass and maximum sustainable yield of common kilka in Iranian waters of the Caspian Sea. The result shown that catch of kilka in Iranian coastal in 2018 decreased from 26153 ton to 24586 ton in 2019. The mean length was 104.3±10.6 at the same time and the minimum and maximum fork lengths were 52.5 and 137.5 mm and always fishes with 3 and 4 year olds had the highest frequency 78.1 and 80.6 percent respectively. The biomass of common kilka was estimated 76922.9 and 74342.7 ton, respectively. In these years, fish of the 3 year of this fish had the highest amount of reserves (respectively 24677.6 and 24254.8 ton) and the lowest reserves for 6-year-old fish, respectively. The breeders biomass of this species is 39557.4 and 36939.4 tons respectively and the ratio of biomass of broodstocks to the whole was 51.4 and 49.6 percent respectively. Acceptable Biological Catch was estimated 19500 tons , with a very cautious approach. The fishing mortality was more than reference points of common kilka at F0.1 and F40% (0.92 and 0.80) , In fact overfishing has occurred . Proper exploiting leads to continuous harvest and long-term stability of storage.

The diameter of the ring connected to the balustrade Conical Lift Net was initially 1.5 m. But gradually the diameter of the attached ring increased Today it is about 4 meters. The seems to increase the diameter of the ring This increased the number of non-target fish in this method. The purpose of this study was length frequency and species composition of non-target fish caught in Conical Lift NetMay 1997 in two fishing ports of Babolsar and Amirabad by four fishing vessels during 33 torrents at a depth of 40-50 m. After identifying the species caught, the total length and weight of the specimens were measured. From a the total of 193 fish caught, the highest and lowest percentage of total relative frequency fish species Alosa caspia were (37.8%)and Gasterosteus aculeatu (4.7%). Relative frequency of other species caught in Babolsar and Amirabad ports Syngnathus abaster were 38.8% and 28%, Gasterosteus aculeatu 50% and 0%, Mugilidae 11.11 and 18.2%, Alosa caspia 0% and 41.7%, respectively. Rutilus frisii kutum was 0% and 12%. The results also show that the frequency of fish caught in Amirabad fishing port is higher than Babolsar fishing port and strongly dependent on area (p < 0.01). The results indicate the high pressure resulting from the production of Bycatch fishing on non-commercial species in Amirabad fishing port. Most frequency in Babolsar and Amirabad fishery ports were respectively in the length class of 4.5-5.5 cm Gasterosteus aculeatu and length class of 15.5-5.5 cm Syngnathus abaster in fish.

This study aimed to investigate the lenght frequency and species composition of fish caught in conical lift-netin May 2018 in two fishing ports of Babolsar and Amirabad by four fishing vessels during 33 torrents at a depth of 50-40 m. After identification, the total length and weight of the specimens were measured. Of the 27967 fish samples examined, the highest relative abundance belonged to Clupeonella caspia (98.98%) and the lowest one Gasterosteus aculeatu (0.032%). Number of fish caught in the Babolsar and Amirabad ports were 27610 and 357, respectively. Out of 193 fishes, the highest and lowest percentage of relative frequency fish specieswere for Alosa caspia (37.8%) for G. aculeatu (4.7%). The relative abundance of other species in the ports of Babolsar and Amirabad are Syngnathus caspius was 38.8 and 28%, G. aculeatu 50 and 0%, Mulets 11.11 and 18.2%, A. caspia 0 and 41.7%, Rutilus kutum 0% and 12%, respectively. The results show that the maximum and minimum frequencies in Babolsar port was 99.86% for Clupeonella caspia and 0.03% for C.engrauliformis and in Amirabad were 65.38% and 6.04%, respectively, for C. caspia and C.grimmi. Among the Kilka fish caught in the two zones, the abundance of C. caspia and C.engrauliformis were highly dependent on the fishing region (p < /em><0.01). The results show that maximum lenght abundance of conical lift net in Babolsar and Amirabad fishing ports are 11.5-12.5 cm.

To investigate spawning time, sexual maturity, and fecundity of kutum, this study was carried out in the Iranian waters of the Caspian Sea during February to April 2019. Samples were taken randomly from the catch composition of 119 beach seines in three provinces of Guilan, Mazandaran, and Golestan. The mean (± SD) fork length and total weight calculated 39.8±5.9 cm and 830.6±360.3 g, respectively. The sex ratio was 1:0.88 (M: F) that was significantly different from 1:1 ratio (p<0.05). Based on the frequency of different sexual maturity stages and the trend of gonadosomatic index (GSI), the peak of the spawning period was the second decade of April. The mean (± SD) absolute and relative fecundity were 45180±12239 and 47.5±8.6 eggs respectively. Absolute fecundity increased by increasing length, weight, and age and had positive and high correlations with these parameters. The length of maturity calculated 36.3 cm (fork length). The results show that the length of maturity and fecundity decreased in the last decade. Fishing pressure and high exploitation, as well as artificial reproduction and release of juveniles to regenerate the stocks of this species, which has caused genetic changes, are among the most important factors in reducing the length of sexual maturity and fecundity. It is recommended to review the fishing and exploitation regulations, to apply time, place, and instrumental restrictions and to provide suitable environmental conditions for natural reproduction and to reduce artificial reproduction and release.

Summary: The catch of Carp (Cpinus carpio) and Roach (Rutilus caspicus) in the southern waters of the Caspian Sea, especially in Golestan province, have been a special status because the major catch of these two species in the Caspian Sea are related to the eastern coast of the Golestan province. This study was conducted to investigate the effect of the size and numbers of fingerling released into the Gorganroud River, decline of the water level in the Caspian Sea and discharge of the river on cpue (catch per unit effort) of these two species. For this purpose, the data on catch and release of two species carp and roach yearly during 1999-2017 from fisheries organization, the data of changes in the Caspian Sea level from the Caspian Sea Research Center and information related to discharge of river water from the Golestan Meteorological Office were prepared. The catch rate and the number of released fingerling of two species carp and roach were fluctuated during this period. During the last four years, the catch share of C. carpio and R. caspicus in Golestan province was decreased in comparison to the total catch rate of these species in the Iranian waters of the southern coast, while the number of release in these four years was increased. The results of this study showed that different factors (sea level, released weight, and released number) simultaneously affect the rate of catch per unite effort (cpue) of two species of carp and roach.

Fish sampling was conducted to evaluate the species diversity of fish in 4 stations in Sanandaj Azad dam ecosystem seasonally from summer of 2017 to spring of 2018. A total of 1057 fish were caught in 12 species, of which more than 80% were caught in the lake behind the dam. The Cyprinidae family had 11 species with the most species diversity and only Sasanidus kermanshahensis belonged to the Noemachilidae family. There was no significant difference between Shannon species diversity in the lake behind the dam (with a mean of 1.11 ± 0.32) and Komaci River (P> 0.05), and in summer with other seasons there was a significant difference (P <0.05). The size and weight of the population living in the lake habitat behind the dam were significantly higher than the population living in the river habitat (P <0.05). Among the identified fish species, 5 species Carrasius auratus, Cyprinus carpio, Hemiculter leucisculus, Hypophthalmicthys molitrix and Pseudorasbora parva are exotic species. Among the influences of exotic fish is its competition with native fish for food, and this will have a significant impact on the species diversity of the fish, population dynamics and fish populations. Also Sasanidus kermanshahensis is an endemic species for Iran, which is very important for protection. Considering the importance of endemic species and the presence of a considerable number of exotic fish species in the Azad dam ecosystem, the results of this study are of considerable importance.

The purpose of Present study was the effect of resizing of Mesh Size on lenght frequency and weight averages, frequency Kilka Fish Catch in Conical Lift Net May 1997 in Babolsar fishing port by four fishing vessels during 33 torrents at a depth of 50-40 m. After identifying the species caught, the total length and weight of the specimens were measured The results showed that in all 4 nets the highest percentage of fishing frequency was from 11.5 to 12.5 cm length range. length range 7.5 - 6.5 in 7 and 9 Mesh Size; . length range 8.5 - 7.5 in 9 Mesh Size; . length range 15.5 - 14.5 in . the length range Mesh Size 7 and 16.5 - 15.5 . the length range in Mesh Size Items 7, 8 and 9 were not observed . the length frequency distribution of common Kilka Catch by funnel net was similar to 4 different Mesh Sizes. there was no significant difference between the average length of common kilka Catch with different Mesh Sizes. And the highest frequency in 8mm Mesh Size with an average frequency of 954. the results showed a correlation between the Mesh size and the total length. No significant correlation was found between the Mesh size and total length of common Kilka. Indicates that the Mesh size of the fountain does not determine the total length.

The changes in biological structure and growth common kilka were investigation during 2008-2017 in the Iranian waters of the Caspian Sea. Kilka fishing ships discharged theirs catch in three ports : Babolsar, Amirabad and Anzali. The sample based on the length of 5 mm were classified class. Fork length ranged from 52.5 to 142.5 mm and mean (±SD) 101.9±10.5 and fish fork length 92.5-112.5 mm of the population have been dominant (81%)(n= 49759). The slight fluctuations in the average length with values ​​between 100 and 105 mm. During this period, fish of +3 and +4 years old have been dominant with frequency of 80-70%. The stability  length and weighted mean of generation growth rate was indicative of relative stability and the average age of common kilka stability, the stability of the population are descendants entered and confirmed. The results showed that in the year 2008 the frequency of young fish 1-2 years was 15.2% of the catch, but gradually in the following years, the abundance of these fish in the hake decreased, so that in 2017, only 10% of the catches were allocated. Reducing overfishing and pressure on young fish stocks is an opportunity to rehabilitate stocks of this species.

This study was conducted to determine the effects of some environmental parameters (sea surface temperature SST, sea level SL and Volga river water volume VRWV) on biomass of golden grey mullet Chelon aurata in Iranian coastlines of the Caspian Sea. In the study, the catch and population parameters of golden grey mullet during the years 1991-2017 used as input data. In these years, the catch of golden grey mullet ranged from 1425 to 6600 mt. The total biomass increased from 10870 mt in 1991-92 to 20950 mt in 2000-01 and then declined to less than 8800 mt in 2017-18. Also, the biomass of 2 years (as recruitment R) increased from 1757 mt 1991-92 to 2617 mt in 2001-02, then declined to 387 mt in 2016-17. There is a significant negative relationship between R-SST (p<0.017), and a positive relationship between R-VRWN (p<0.024) and R-SL (p<0.002). By using stepwise regression, among three environmental parameters, only SL had significant effects on R biomass (R2 = 0.339). It seems that the SL has the main role in the biomass of golden grey mullet in the Caspian Sea. Therefore, an ecosystem-based approach to Management is required to sustainably exploit of golden grey mullet stocks in the Caspian Sea.

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.