عباسعلی اقایی مقدم

The aim of this study was to investigate the effect of adding cottonseed meal and a mixture of organic acids to the diet on growth parameters, economic justification, and nitrogen and phosphorus retentions in rainbow trout. For this purpose, six triplicate treatments consisting of six diets were considered in a 3 × 2 factorial design, where two levels of cottonseed meal (0% and 15%) and three levels of organic acid mixture (a mixture of lactic acid, citric acid, and potassium sorbate in equal proportions) at 0%, 0.5%, and 1% were added to the diets. A total of 270 rainbow trout with an average weight of 14.0 ± 0.35 g were stocked in 18 aquaria containing 40 L of water, with a density of 15 fish per aquarium. The above diets were offered to the fish for 8 weeks at a daily rate of 3 to 4 % of biomass. The aquariums were equipped with a semi-closed system including aeration, physical filter, biological filter, and UV filter, with a daily water exchange of 30% during the experimental period. After the feeding trial, sampling of the fish muscle was conducted. The results of this study showed that adding cottonseed meal to the diet had no significant effect on final weight, fish production per unit volume of water, or feed cost; however, it significantly reduced the growth rate and increased feed conversion ratio. Additionally, adding organic acids to the diet had no significant effect on fish growth parameters. The addition of cottonseed meal to the diet did not significantly affect the phosphorus and nitrogen content in the fish muscle; however, adding organic acids to the diet significantly increased the phosphorus content in the fish muscle. Overall, the results indicated that cottonseed meal could be used at a level of 15% in rainbow trout diet. Although this amount of cottonseed meal significantly reduces growth and increases feed conversion ratio, it does not have a significant economic impact on trout production. Furthermore, adding organic acids at levels of 0.5% to 1% to the trout diet, while having no positive effect on growth, efficiency, or feed cost, does increase the phosphorus content in the fish muscle.

Aquaculture development is challenged with limitation and high costs of supplying protein diets, so searching for alternative protein sources in fish diets is inevitable (Tacon, 2020). Insect meals are considered as a promising substitution protein ingredients last decades (Alfiko et al., 2022). Among candidates’ insect meals, Silkworm is well-balanced in protein as well as lipid and can be served as feedstuff (Mahanta et al., 2023). A study conducted to investigate if low level of silk worm pupa inclusion in fingerling Beluga sturgeon (Huso huso) diet could provide a protein source replacement accompanying with high benefit for the species.

Fingerling Beluga sturgeons (5±0.2 g, mean±SE) fed with experimental diets for a period of 8 weeks. Four experimental diets includes: no (SWP) inclusion as a control treatment (T0), 5, 10 and 15 percent (SWP) substitution referred as (T5, T10 and T15) treatments. At the end of the experiment, Weight Gain (WG), Specific Growth Rate (SGR) and Feed Conversion Ratio (FCR) calculated to assess the diets quality on fish production. Hepatic enzyme (ALP, AST, and ALT) and serum biochemical (IgM, total protein and lysozyme) analyzed for revealing the health status of fish.

(SWP) treatments, in particular (T15) had a significant increase in (WG) compared to the control group (p<0.05). (SGR) as well as (CF) in (SWP) treatments showed no significant differences compare to the (T0) (p<0.05). (FCR) was significantly improved among (SWP) treatments, although the difference was not significant (p<0.05). Serum lysozyme, Serum immunoglobin and total protein in (T10) and (T15) were significantly increased compared to the control group, (T0) (p<0.05).

Our findings indicate the protein level adjusts and fixes with the (SWP) was efficiently enough to be replaced with fish meal in fingerling Beluga sturgeon (H. huso). The results of (SGR) as well as (CF) suggest that the replacement level could be changes to more to get a differently improved result. Hepatic enzymes showed that (SWP) did not affect impairment in digestive tract.  What’s more, blood biochemical analysis showed that (SWP) can have immunomodulatory effects on fingerling Beluga sturgeons (Zhou et al., 2022)

This research was conducted in order to investigate the effect of adding salt and Bacillus subtilis bacteria (IS02) to the diet on the survival, cortisol response and antioxidant indices of sea carp, Cyprinus carpio, under salinity stress. Baby carp fish (average 1.1 g) were fed with diets containing 5 and 10% salt or 108 x 5.2 and 109 x 5.2 colony grams (cfu/g) of probiotics for 15 days and then to They were directly transferred to saline water with a concentration of 13 grams per liter and samples were taken after 3 and 10 days. Survival in all treatments was above 96%. The amount of cortisol at baseline and after salinity stress in probiotic treatments was significantly lower than other treatments. Superoxide dismutase activity was higher in probiotic treatments than other treatments. Diets had no significant effect on catalase activity. Based on the results of this research, the use of B. subtilis in the diet can reduce stress and increase the antioxidant capacity in juvenile Norse carp.

This study used a dynamic model to predict the fishing status of the Persian Sturgeon (Acipenser persicus) along the coast of the Golestan province in the Caspian Sea. The findings indicated that based on the initial population in 2017 equal to 2500 samples of fish if harvested at the current rate, the stocks of this valuable sturgeon fish will be destroyed in the next 50 years. However, when considering the harvest rate of 0.2 per year (nearly half of the current catch), the amount of fish harvested will increase so that this stock will completely regain its ability to regenerate itself.

Wetlands are a critical part of our natural environment and they can reduce the impacts of floods, absorb pollutants and improve water quality. This survey was conducted at 7 stations in three international wetlands Alagol, Almagol and Ajigol wetlands between February 2017 and November 2018. Results showed that water quality characteristics are somewhat in good conditions but amount of phosphates, was more than standard in summer at Alagol and in Autumn and winter at Ajigol. In this study, 57 different species (25 Bacillariophta, 12 Chlorophta, 9 Cyanobacteria, 5 Pyrophyta, 3 Euglenophyta and 2 Xanthophyta and Carophyta) were identified. Bacillariophyta was dominant in all seasons, however Cyanophyta in Alagol and Ajigol wetlands and Pyrophyta in Ajigol were dominant in summer. In the study of water quality index (WQI), it was observed thatexcept in summer and autumn in Ajigol wetland in other seasons of the studied wetlands were in good quality. It seems that the Atrak river as the main source of water supply for these wetlands, is the place where high amounts of agricultural and rural effluents are received, which practically enter these wetlands, appropriate management and corrective measures should be taken.

Estimation of initial production capacity is one of the important principles of water resources assessment and management. Due to the size, depth and different positions of wetlands (inlet area, middle and near the dam base) of some physicochemical parameters of water, plankton (phytoplankton and zooplankton), macrobenthos and fish from 3 stations, in Alagol wetland, 2 stations in Ajigol wetland and 2 stations in Almagol wetland were sampled for one year from winter 2016 to autumn 2017. Comparison of the three wetlands, the results showed that in all seasons, the highest biomass per hectare was observed that phytophagus fish and zoophagus fish in Ajigol is much higher than the other two wetlands. Regarding benthic fish biomass, most biomass was observed in spring, summer and winter in Almagol wetland and in autumn in Ajigol wetland. The highest abundance in all three wetlands is related to Gambusia and in excluding Gambusia fish, the highest abundance in Alagol wetland is related to crucian carp, in Ajigol capoeta and common carp and in Almagol, crucian carp and in relative weight, phytophaguus and crucian carp were the dominant fish. Also, catfish are found only in Alagol lagoon. It seems that the role of releasing benthic fish such as common carp should be considered more and invasive fish should be controlled.

This study aimed to investigate the effect of salt (sodium chloride) supplementation in the diet on survival, biochemical indices, and tissue histology of juvenile wild common carp under salinity stress. Fish fry (approximately 1.1 g) were fed diets containing 0%, 5%, and 10% sodium chloride for 15 days, then directly transferred to brackish water (13 g/L) and sampled after 3 and 10 days. Diet or sampling time had no significant effect on survival and body moisture of fish. Sodium, glutathione reductase, and glutathione peroxidase levels in the body significantly increased three days after salinity stress, and returned to pre-stress levels after 10 days. Body moisture levels significantly decreased after salinity stress, but potassium and chloride levels in the body increased and remained significantly higher than pre-stress levels for up to 10 days. Prior to salinity stress, glutathione levels were higher in high salt treatment groups compared to control groups, and 10 days after salt stress, glutathione levels were higher in the 10% salt treatment group compared to the other two groups. Malondialdehyde in the body was significantly lower in sodium chloride treatments than the control. No significant and important histological lesions were found in the fish gill and kidney after salinity stress. This study suggests that wild carp fry can tolerate direct transfer to the Caspian Sea brackish water, without dietary sodium chloride supplementation. Dietary 10 g/kg salt supplementation decreases lipid peroxidation in the fish.

Sedative agents are utilized to mitigate stress and improve fish welfare during and after transportation. 

We aimed to assess the effects of myrcene addition to the transportation water on the plasma biochemical profile of common carp, Cyprinus carpio. 

For this purpose, common carp (mean weight of 45.3±1.65 g) were transported in plastic bags containing myrcene at concentrations of 0 (CTL), 10 (10 M), 20 (20 M), 30 (30 M), and 50 (50 M) µL/L for 6 h. Then, their plasma parameters were compared to those values before transportation (BT). 

Transportation significantly (P<0.05) decreased plasma total protein, albumin, alternative complement, lysozyme, sodium, and chloride, while increasing potassium, calcium, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase in the CTL treatment, as compared to BT. Adding 50 µL/L myrcene to water prevented total plasma protein and albumin loss. Supplementing 20 µL/L myrcene to water prevented or reduced the changes in plasma ions, alanine aminotransferase, and alkaline phosphatase. Addition of 10-50 µL/L myrcene to water decreased the changes in plasma aspartate aminotransferase. Adding 20 and 30 µL/L myrcene to water mitigated the changes in plasma alternative complement, as 30 µL/L myrcene increased plasma lysozyme activity. Transportation and myrcene addition had no significant effects on plasma immunoglobulin (P>0.05). However, a significant increase was observed in plasma globulin in the 20 M treatment (P<0.05). 

In summary, adding 20 µL/L myrcene to the transport water of common carp reduced hepatic enzyme levels and improved immune parameters, and therefore, the use of myrcene improves fish welfare during transportation.

This study was conducted to investigate the effect of adding Bacillus subtilis (IS02) to the diet on survival, biochemical indices, and histological alternations of juvenile wild common carp, Cyprinus carpio, exposed to salinity stress. Juvenile common carp (about 1.1 g) were fed diets containing 0 (control), 2.5 × 108 (pro-8), and 2.5 × 109 (pro-9) cfu/g probiotic for 15 days and then transferred directly to brackish water (13 g/L) and sampled after 3 and 10 days. Diet and sampling time had no significant effect on fish survival, which was above 96% in all treatments. Body moisture and potassium were only affected by sampling time, with moisture decreasing significantly after salinity stress while potassium increased significantly. Whole body sodium in pro-8 treatment did not change significantly during salinity stress, and probiotic treatments had lower chloride levels than the control before and after salinity stress. Adding probiotic to the diet increased glutathione reductase, glutathione peroxidase activity, and reduced glutathione concentration, while decreasing malondialdehyde concentration. Probiotics caused white blood cells infiltration in the kidney tissue. No significant tissue damage was observed in the gill and kidney, compared to the control after salinity stress. This study shows that juvenile wild common carp can tolerate direct transfer to the Caspian Sea without dietary probiotic supplementation. However, probiotic stimulates the kidney immunity, enhances ionoregulation, and increase antioxidant capacity in fish, which can have beneficial effects under field conditions.

Organic acids and their salts are known as appropriate substitutes in feed for improving the health, growth, and performance of fish.  The present study was conducted to determine the effects of dietary lactic acid supplementation on immunological factors, hepatic enzyme activity, and plasma proteins in common carp, Cyprinus carpio. The fish were fed the diets mentioned above for 56 days, then their growth performance, humoral immunity, and plasma hepatic enzymes were assessed. A total of 180 fish (mean weight=25 g) were randomly distributed in twelve tanks (150 L water in each tank) as four treatments, fed diets containing 0, 2.5, 5, and 10 g/kg lactic acid (T0, T1, T2, and T3, respectively). At the end of the feeding trial, T2 showed significantly higher growth performance than T0. Plasma total protein, albumin, and globulin levels of T1-T3 were significantly higher than that of T0. However, plasma protein levels decreased significantly by elevation in dietary lactic acid concentration (10 g/kg). No significant differences were observed in plasma aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activity among the treatments, although alanine aminotransferase (ALT) activity decreased significantly in fish-fed dietary lactic acid supplementation (T1-T3) compared with the control group (T0). All humoral immunity parameters (lysozyme, complement, immunoglobulin, and bactericidal activity) increased significantly in T1-T3 treatments compared to the T0 group. Overall, dietary lactic acid supplementation improves growth performance, humoral immunological parameters, and hepatic health. According to the results, dietary lactic acid (2.5-5 g/kg) is recommended for preparing common carp feed.

To investigate fish biodiversity indexes of Roodbabol River and their relationships with environmental factors, sampling was conducted at 20 stations. At each sampling station factors including river depth, river width, water velocity, substrate rubble diameter, temperature, dissolved oxygen, electrical conductivity and altitude were measured. 6 freshwater fish species has been recorded namely Barbus (Luciobarbus capito), Hiircan Crested Loach (Paracobitis hircanica), Iranian Goby (Ponticola iranicus), Tabarestan Spirlin (Alburnoides tabarestanensis), Grass Carp (Ctenopharyngoden idella), Crucian Carp (Carassius carassius), and Rainbow Trout (Oncorhynchus mykiss). Shanon diversity and Simpson dominance indexes were the highest at station 6 (H′= 1.068 and λ = 0.6071) and 7 (H′= 1.212 and λ = 0.6653) and the lowest at station 9 (H′= 0.103, λ = 0.041). Stations 7 and 13 were the richest stations for species richness index (0.9705 and 0.8736, respectively) while stations 9 and 11 showed the lowest species richness (0.2597 and 0.2153, respectively). The most and least values of Pielou′s evenness index were observed at stations 11 and 20 (0.9816 and 0.3435, respectively). Water temperature with fish abundance, Margalof, Shannon diversity and Simpson dominance indexes, river depth with fish species number, and river width with Pielou′s index had positive and significant correlation. In addition, a significant and negative correlation was discovered between electrical conductivity with Margalof index and between river width with fish abundance. PCA indicated that factors like depth, velocity, rubble diameter and river width primarily and other factors of altitude, salinity and shadow level secondly affect some fish species abundance in particular stations.

This study was conducted to investigate the possibility of breeding carp juveniles (Cyprinus carpio) in pen conditions in Gorgan Bay in two treatments with a density of 2 and 4 pieces per square meter in order to produce breeders for restocking centers. The first juveniles were raised in earthen ponds with concentrate feed. Then, with an average weight of 93.87± 32.66g, they were transferred to pens with an area of 50 m2each and 16 mm mesh size, in Gorgan Bay. 6 pens were considered for this research and for each treatment, 100 and 200 pieces of juveniles were considered in each pen. Feeding was done with concentrate feed and physical and chemical factors and biometry of fish were done regularly. The results showed 52% survival in first treatment and 49% for second treatment and the mean weight for two treatments were 410± 64.98 and 390±52.8. Results showed that there was no significant differences between weight and length in two treatments. The histological results showed that the male and female were mature in 4th stage. The eggs of the female fish were between 800 and 1200 microns in diameter.

The aim of this study was to investigate the effect of adding lactic acid to the diet of rainbow trout on growth indices, activity of digestive enzymes and microbial flora of the fish gastrointestinal tract. For this purpose, 4 diets containing 0, 5, 10 and 20 g of lactic acid per kg of diet were made and each diet was offered to fish in three replications for 8 weeks. The results showed that there was no significant difference in growth and survival indices between different treatments (P> 0.05). The highest activity of gastric pepsin enzyme was observed at the level of 10 and 20 g of lactic acid in the diet (P <0.05). The highest alpha-amylase activity was observed at the level of 10 g of lactic acid in the diet (P <0.05). Lipase activity in the control treatment and 10 g of lactic acid in the diet was similar and significantly higher than the treatments of 5 and 20 g of lactic acid in the diet (P <0.05). Intestinal protease activity in treatments of 5 and 10 g of lactic acid in the diet was higher than the control treatment and the highest activity was related to 10 g of lactic acid (P <0.05). Treatment of 20 g of lactic acid in the diet had lower protease activity than the control treatment (P <0.05). The highest number of total intestinal bacteria was observed at the level of 5 and 10 g of lactic acid in the diet (P <0.05). The number of intestinal lactic acid bacteria in lactic acid treatments was significantly higher than the control treatment (P <0.05). The highest number of lactic acid bacteria was observed in the treatment of 10 g of lactic acid in the diet (P <0.05). According to the results, the addition of lactic acid to the rainbow trout diet has no effect on growth, although it does increase the activity of digestive enzymes. However, adding 10 g / kg of lactic acid leads to an increase in lactic acid bacteria in the gut of the fish.

Due to use of ovulin hormone in the carp breeding centers and lack enough information about the effect of its different concentrations on this fish broodstocks, evaluation of the effectiveness of ovulin hormone in artificial reproduction of carp is essential. This study was performed on 12 male broodstocks of carp with an average weight of 1307.85±169.57g. Fish in 4 groups (each group with 4 fish) were injected at doses of 0.2, 0.25, 0.3 and 0.35mg/kg body weight of ovulin hormone in one time. The injection method was performed peritoneally and below the pectoral fin. Blood samples were taken from fish in two times, before injection and 10 hours after injection. Based on the results, it was found that injection of different doses of ovulin hormone had no effect on red blood cell counts (RBC), mean corpuscular hemoglobin (MCH) and white blood cell counts (WBC) (P>0.05). However, the amount of hemoglobin, hematocrit and granulocytes in all treatments decreased in the blood of male broodstock after the injection of ovulin hormone and the percentage of monocytes increased (P <0.05). It had no effect on total protein and sodium (P>0.05). However, glucose and calcium levels increased and triglyceride, albumin and potassium levels decreased in the studied doses (P<0.05). The levels of cortisol and sex hormones testosterone, estradiol and progesterone in male broodstocks increased in all doses studied (P<0.05). Also, the highest sperm motility and spermatocrit were observed in 0.2 mg/kg, pH in 0.3 mg/kg, triglyceride and alkaline phosphatase in 0.35mg/kg and calcium, sodium and potassium in 0.25mg/kg (P<0.05). The results of this study showed that doses of 0.25 and 0.3mg/kg body weight had the best effect on blood indices, steroid hormones and sperm indices in male broodstocks of carp.

In the last two decades, the Caspian Sea has faced various ecological events, such as harmful algal blooms and increasing in the trophic level. It is necessary to conduct monitoring studies in this water body, because of applying the Caspian Sea for fisheries activities. The objectives of the present paper are the study of algal bloom potential and trophic level in the Iranian coastal of southern Caspian Sea up to 30m depth, during the year of 2018-2019 as well as the comparison of the obtained results to the condition in previous years. Boundary lines for the beginning of blooms (annual median+5%) based on the chlorophyll-a concentration, abundance, and biomass of phytoplankton were obtained 2.02 (mg/m3), 176 (million cells/m3), and 312 (mg/m3), respectively. The lowest percent frequency of bloom (13%) was recorded in spring and summer based on the chlorophyll-a, abundance, and biomass of phytoplankton, respectively. According to calculations based on the accumulation of the aforementioned parameters, water has excellent quality (oligotrophic state) in summer and moderate quality (mesotrophic state) in other seasons. An interannual study of trophic states showed oligotrophic, mesotrophic, oligo-mesotrophic, and mesotrophic level in 1996-97, 2009-10, 2013-2014, and 2018-2019, respectively. The highest seasonal abundance of species (187 cells/ml) was recorded in Pseudonitzschia seriata. This species is considering a serious ecologic problem and decreasing water quality in the winter season. The bloom potential of Pseudonitzschia seriata was obtained in the “medium density” group. It should be noted that the increasing trend of inter-annual trophic levels is the alarm of environmental health and show the ability of the ecosystem to thrive the harmful algal blooms. The environmental alarm is more emphasized in the central region (with a history of macroscopic toxic algal blooms) because the water quality in the central area (medium quality) was lower than in the eastern and western areas.

Presence-absence and abundance of each fish species in a river habitat depends on several factors and they prefer a specific range of each habitat factor. The present study was carried out to investigate habitat suitability index of Capoeta capoeta and the effect of habitat factors on its distribution and abundance in Roodbabol branch of the River Babolrood (Mazandaran Province). To do, fish sampling was performed at 20 sampling stations during December 2017 and January 2018 and 11 habitat factors were measured at each sampling station. Then, habitat suitability curves for each parameter and suitability index of each station were obtained using HABSEL software. Also, determination of distribution pattern of C. capoeta and its relation with the best habitat factors were surveyed using dbRDA analysis according to its abundance at each station in Primer+Permanova (Ver. 6).Based on the HABSEL results, C. capoeta inhabiting in Roodbabol prefers wide locations with low water flow speed, temperature between 14 to 18°C, average depth (22 to 30 cm), average altitude (140-180 m), average EC (260-300 μS/cm), small grain size of substrate rocks (100-125 mm), high level of dissolved oxygen (12 to 13 mg/l), and average salinity (1.5-1.7 mg/l) which are covered by bush and shrubs and shadow level is 41-70%. Also, dbRDA graph based on DistLm model indicated that factors of depth and width in the first order and water flow with EC in the second order affected the abundances differences of C. capoeta among various stations.

This project carried out between Augest in 2017 and October in 2018 in the Golestan Dam. A questionnaire was prepared from the household of 4 villages: Gharajeh, Arab Sorang, Agh Abad and Sarjeh Kor. Statistical Methods of Krumbachchr('39')s alpha were used to analyze the questionnaires. The most commonly used scale in social research is the Likert comparison were used to test the validity of the questions. Topsis method was used to investigate the power of effective factors and prioritize it. The Logit model was used to identify descriptive variables and their relationship with event occurrence and eventually an estimate of the probability of occurrence of an event for a particular person. Chi-square test was used to study the effect of gender and age on social and economic parameters. The results of model estimation using the Logit method showed that age, gender and interval variables at each level of 10%, employment at the level of 5%, and migration at the level of one percent, affect the willingness of the people. The results of weighting the criteria using the entropy method indicate that the criteria for improving the economic situation, increasing income in rural communities of the region, employment related to aquaculture, improving the lives of villagers, and increasing aquaculture employment are one of the most important social impacts of this activity. The results of this study showed that fish farming in cages of Golestan Dam can directly affect employment creation, improve economic situation in the region, tourism and reduce rural migration to cities. On the other hand, protein production can have a significant impact on the per capita consumption and nutritional health of residents.

*, This study carried out to determining the normative of artificial and semi-artificial reproduction of wild common carp (Cyprinus carpio. L. 1758) in 2019. In this study, 70 samples were caught from Gomishan region. Mean weight and length of 29 wild males were 1146±151.62 g and 44.79±2cm, and for 41 wild females were 1152.25±235.14 g and 44.87±2.4cm, respectively. Mean age of males were 7.16±0.75 and females were 9.5±0.67 years old, respectively. Artificial and semi-artificial propagation methods were performed. Artificial propagation was done by Ovulin injection in two steps for females at 1 ml / kg fish weight and half the dose was injected at the same time in the second stage of female infusion after 12 hours for males.14 males and 13 females broodstocks for artificial, and 7 and 10 for semi-artificial propagation were selected. The number of eggs per gram was 783±53. The fertilization rate was 91±4 and hatch rate was 58±7.23.Maximum and minimum relative fecundity were 209707 and 61200 per kilogram of body weight and Maximum and minimum working fecundity were 325728 and 53244 respectively. Mean relative and working fecundity was 104795.6±49663.32 and 128981.5±84102. Hatch rate was 58±7.23. A total of 729800 larvae were transferred to the Sijaval Center pond . 200000 juveniles with 0.8g weight and 36500 juveniles with 2.6g weight producing of semi artificial propagation rearing in Gharasu River in order to restocking. For reproduction of wild common carp, choosing the broodstocks in right time (in winter), region of catching, transfer it from the sea to breeding centers are the most important effective point. Therefore, the manipulation, relocation and transfer of these newly catch wildlife from the shores of the sea or river requires equipment, handy net, disinfect materials, anesthesia, Oxygen tank and time table.

This study was carried out in Shahid Marjani Farm to identify the occurrence of helminth parasites in digestive tract of Iranian Sturgeon (Acipenser persicus) in 2016 and 2017. In 2016, 2 Species of Skrjabinopsolus semiarmatus and Cuculanus sphaerosephalus from 11 specimens (mean total length and weight of 160.54 ± 8.6 cm and 31.62 ± 6.72 kg, respectively) and in 2017 just one species (C. sphaerosephalus from 12 specimens (mean total length and weight of 158.3 ± 1.1 cm and 29.3 ± 4.9 kg, respectively) were collected. Incidence in 11 samples were 72% and mean intensity was 6 ± 2.87 for C. sphaerosephalus and incident was 27% , and mean intensity was 3.17 ± 3.25 for S. semiarmatus in 2016. In 12 samples incidence was 50%, and mean intensity was 6 ± 2.87 for C. sphaerosephalus in 2017. results showed the highest rate of incidence was belonged to C. sphaerosephalus. The number and type of gastrointestinal parasites in Iranian sturgeon compared to previous years decreased in southeast of the Caspian Sea that can be the result of changing diet and reducing the host interface.