فصلنامه شیلات
سال هفتاد و پنجم شماره 1 (بهار 1401)

Anionic detergents make up a large portion of domestic wastewater due to their high consumption. With the entry of wastewater into water sources, these substances enter the aquatic environment and cause serious damage to aquatic animals, including fish, by reducing dissolved oxygen in water and causing stress. The aim of this study was to obtain evidence to determine the effect of these substances on the embryonic growth of rainbow trout. For this purpose, rainbow trout eggs and embryos were exposed to doses of 1 mg / l of washing powder, 0.5 mg / l of dishwashing liquid, 0.25 mg of bleach in different stages from fertilization to hatching and sampling was done during this period. The treatments were tested for embryonic growth time, percentage of eyeing, percentage of mortality, appearance and cortisol levels of eggs and embryos. The results showed that detergents accelerate the stages of embryonic development, increase the mortality rate, reduce the percentage of eyeing, induce stress and increase cortisol and cause fetal abnormalities. In general, it can be concluded that the entry of domestic and industrial wastewater and subsequently entry of detergents into water sources can cause toxic effects and irreparable damage to aquatic species

The aim of this study was using the silver carp skin wastes as a potential source of collagen and recovering the soluble collagen in acid and enzyme solution by isoelectric precipitation method. The physicochemical properties of produced collagen investigated as well. Hence, collagen was extracted from the skin of silver carp by acidic and enzymatic methods. Then, soluble collagens were recovered using isoelectric precipitation (Isoelectric-Acid-soluble collagen (I-ASC) and Isoelectric-Pepsin-soluble collagen (I-PSC)) and salting-out (Acid-soluble collagen (ASC) and Pepsin-soluble collagen (PSC) methods. The results showed that the extraction yield and total protein content of ASC and PSC samples were higher than I-ASC and I-PSC samples. But the production yield was the same in all the samples. The high purity of I-ASC and I-PSC collagens represented different total protein content and extraction yield, however similar production yield. The SDS-PAGE pattern confirmed the structure of I-ASC and I-PSC as type I collagen. In addition, the amino acid composition showed high amino acid content for I-PSC. It was estimated that the thermal denaturation temperatures for I-ASC and I-PSC samples laying at 28.70°C and 29.99°C, respectively. Finally, the investigation of collagen solubility at different pH levels and concentrations of NaCl showed that the solubility decreases with increasing ion concentration of the solution, and increases at the pH above and below the isoelectric point. Overall, the results showed that the isoelectric precipitation of soluble collagen produces a high-purity collagen protein that could be an alternative source to replace mammalian collagens.
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Scomberomorus guttatus (Bloch and Schneider, 1801) is one of the most important commercial fish of the Scombridae in the southern waters of Iran, which plays an important role in the human diet. The catch of this species has increased in recent years, and due to the limited data available on its stock in southern waters, it is not possible to use models based on complementary data to assess its stock. In the present study, the catch-maximum sustainable yield (CMSY) and the Bayesian surplus production (BSM) models were used to determine the sustainable exploitation and fisheries reference points of Scomberomorus guttatus caught in the southern waters. Data related to the last 23 years from 1997 to 2019 were collected and entered into the model to calculate fisheries reference points. According to the results, it seems that the BSM model applies the estimates with less sensitivity. The calculated value for B/BMSY by the CMSY model was estimated to be more than 1.0 and the value of F/FMSY was less than 1.0, which indicates the healthy stock status of this species in the southern waters of Iran. By applying the forecasting model, the increasing trend of fishing was predicted in 2033. If this trend continues, the value of B/BMSY will fall below 1.0 and the value of F/FMSY will increase to about 1.99. If the catch is not reduced from 2028, the stock will start to decrease in the years after 2030 and will be overfished. Based on the obtained fisheries reference points, the maximum sustainable yield (MSY) was estimated as 9,000 tons, and this amount was predicted to be 15,000 tons in 2033. In general, the estimated fisheries reference points in this study can be an effective aid in understanding the status of Scomberomorus guttatus stock in the southern waters of Iran and reveal the effects of the application of management policies on its stocks, which can ultimately develop compatible management plans for proper exploitation of its stocks in the region.

Beluga is one of the important endangered species in the Caspian Sea and the main farmed species of sturgeon in Iran. Therefore, the idea of ​​using the growth stimulants through the feed under the low water temperature can be useful for improving its growing efficiency. In this study, 120 fish with the mean weight of 440.15 ± 23 g were fed different animal protein-based diets containing zero, 5, 10, and 15 grams of taurine/kg (Considering the amount of taurine in the basic diet, the amount of total taurine in the diets reached to 3.1, 8.3, 13.0, and 18.1 g / kg, respectively), and reared at 10 ± 1 °C for a 56 –day period. The results of growth indicated a significant and positive effect due to presence of taurine in diet comparing the control treatment. In fact, all the three doses were able to improve the feeding and growth of fish, and the highest percentages of weight gain, specific growth rate, and the lowest food conversion ratio were obtained in treatment containing 8.3 g taurine in diet (a treatment that received an additional 5 g / kg taurine). There were significant differences in condition factor, liver and visceral indices among the treatments (p >0.05), and no mortality was observed among the experimental treatments as well. Also, the highest amylase, lipase and protease enzymes activities were measured in 8.3 g taurine treatment. While the concentration of taurine increased in the diet, the carcass lipid and ash percentages decreased and the protein and moisture percentages increased without any significant difference (p >0.05). Different concentrations of taurine had little effect on nonspecific immunity of fish. Whereas, there were not significant differences in the lysozyme enzyme activities, total immunoglobulin and C3 complement (p >0.05). The highest amount of C4 complement was measured in 8.3 g taurine treatment, which was significantly different compared to other treatments (p <0.05). As a conclusion, the diet containing 5 gr/kg taurine could be the optimum growth stimulant diet, and it can improve the growth efficiency of Beluga fish at the low water temperature (10 ± 1 °C). 
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Algae as a new potential sources and active agents, have attracted many researchers in the field of pharmaceutical, medical and nutrition. Sargassum ilicifolium a seaweed that grows in the coastal and northern regions of the Persian Gul, may have unique nutritional and pharmaceutical effects because of fucoidan, one of the polysaccharides found in this seaweed. This survey, after extraction of fucoidan, have been conducted on its anticancer effects such as MTT assay, cell culture, viability and apoptosis. According to the results, within 24 h, cell viability at 1mg/ml of the extract reduced by 2% and at concentration of 60 mg/ml, reduced less than 30% and the IC50 was 20-30 mg/ml. Also the results obtained from ELISA showed apoptosis was induced by the extract on cancer cells.

The most important factors affecting water quality are its physical, chemical and biological properties. Considering how water quality is one of the main and influential factors in aquaculture, in this study, the trend of fish growth and changes in water quality in dual-purpose rainbow trout farming ponds in Sistan region were studied. For this purpose, biometry of fish and water quality conditions were performed by sampling fish and water, respectively from five pools in Zabol, Zahak, Nimroz, Hamoon and Hirmand cities. Sampling was performed monthly from December to April (simultaneously with the breeding period) from all pools. The highest and lowest production rates are related to Hamoon pools (1039.44 kg) and Zahak (913 kg), respectively. The highest final length and weight of fish was recorded in Hamoon pool with 26.3 cm and 366 g. Measured factors included water temperature, dissolved oxygen (DO), pH, salinity, transparency, electrical conductivity (EC), hardness, alkalinity, nitrite, ammonia, sulfate, carbon dioxide (CO2), phosphate and nitrate. The results showed that the amount of dissolved oxygen between 7.76 to 8.34 mg.l-1, phosphate and nitrate between 0.4 to 1.6 and 0.4 to 1.9 mg.l-1 respectively, EC between 1/95 to 5.5 mmhos.cm-1 and pH ranged from 7.5 to 7.93. These results showed that water temperature changes, as the most important factor limiting the breeding of rainbow trout in this region, in the cold seasons of the year is in the optimal range for breeding this fish and in different ponds of Sistan region is not considered a limiting factor. Changes in water temperature during the breeding period in these areas varied between 14.78-15.24. Other water quality indicators were also in the optimal range for breeding this fish and not much change was observed in the pools of this area.

One of the most important stages of domestication in each species is to maintain the animal in a rearing condition up to reaching to maturity and reproduction. Therefore, this study was performed with the aim of reproducing the pikeperch (Sander lucioperca) grown in a captivity condition. For this purpose, two groups of fish including control group (without hormone injection) and hormone induction group (HCG injection at 200 IU/kg) were considered and each group consisted of two replicates and 5 fish in each tank. The results showed that the fish spawned after 74 to 90 hours, but the difference between the two groups in this regard was not significant. The latency time was determined in case of degree-hour in non-injected breeders to 1396.9 ± 157.2 and in injected breeders to 1261.5 ± 34.2 degree-hours (P = 0.356). The response rate of fish in non-injected breeders was 87.5 ± 17.7% and in injected breeders was 75 ± 0.0% (P = 0.423). The quality of nests did not show any significant difference between the two groups. Fertilization rate was 87.3 ± 3.5% in non-injected fish and 82.7 ± 5.4% in injected fish (P = 0.412). According to the obtained results, it can be concluded that due to the complete adaptation of farmed fish to the captive rearing condition, it can be possible to propagate pikeperch without hormonal induction while the desired temperature and suitable spawning ground are available.

This study was performed to investigate the effect of increasing pomegranate peel extract in the diet of common carp on inhibiting the oxidative damage from experimental cadmium poisoning. In this experiment, fish weight with an average of 70 grams were randomly divided into the five experimental groups. Experimental unite was an aquarium with the capacity of holding twenty120-liter of water. The first group was considered as control. The second group received cadmium chloride, while the third group was treated with cadmium chloride and pomegranate peel extract (1% of dietary weight), the fourth group received cadmium chloride and pomegranate peel extract (2 % of diet weight) and the fifth group received cadmium chloride and pomegranate peel extract (4% of diet weight) for a 30- day culture period. At the end of the test period, hepatic markers of alanine, aminotransferase, aspartate, aminotransferase, and alkaline phosphatase and catalase were measured in the serum. The results showed that the amount of the above enzymes in the groups treated with cadmium chloride increased significantly compared to the control group (p <0.05). Also, the addition of increasing concentrations (1, 2, and 4%) of pomegranate extract significantly reduced all liver parameters compared to the group treated with cadmium chloride (p <0.05). The catalase enzyme was increased in the cadmium-treated group compared with the control. Based on the findings, it can be concluded that increasing pomegranate peel extract in the diet of common carp can have modulatory effects on biochemical changes in liver enzymes and catalase.

The role and importance of benthic organisms in the food chain and ecological pyramid of aquatic ecosystems is highly recognized. This study was conducted to investigate the benthic population and water quality of Karaj River, located in Alborz Province. In this study, a total of four stations along the river were selected and their benthic fauna were sampled seasonally. Samples were fixed with 4% formalin, isolated, identified, and counted in the laboratory. In the sampling procedure, 24 families, 5 categories and 5 orders were identified. The highest benthic density with 177 specimens (number per square meter) was reported in summer and the lowest benthic density with 105 specimens reported in winter. The benthic population and composition of Karaj River benthic was consisted of two classes of Oligocheata, Platyhelminthes and Coleoptera order and these groups had the highest density in all stations. During this study, the average Shannon-Wiener diversity index was 1.61. The highest Shannon-Wiener diversity index in the first station was 1.92, Based on the Hilsenhof Biological Index (HFBI), resulting that the water quality of Karaj River classified at the levels of good to desirable.

In the present study, the effect of various feeding strategies during 60 days and subsequent re-feeding over the next 60 days was evaluated to achieve the compensatory growth on growth performance and biochemical parameters in great sturgeon Huso huso. For this purpose, two hundred and forty fish with a mean individual weight of 67.10 ± 1.10 g (Mean ± SD) were divided into four feeding strategies groups: satiation feeding (100%), 75% satiation feeding (75%), 50% satiation feeding (50%), and 25% satiation feeding (25%). In the second phase, all groups were fed to satiation. Blood sampling was performed at the end of feeding trial (120 days) to measure biochemical parameters. At the end of first phase, final weight in the satiated group (100%) was higher than the other groups while it decreased with increasing dietary restriction (p < 0.05). Specific growth rate and mean individual weight increased significantly in 75% and 100% satiation feeding compared to the other treatments (p < 0.05). At the end of second phase, there was not significant differences in the final individual weight, total length, weight gaine and specific growth rate among treatments (p > 0.05). Hematocrit was affected by dietary strategies and in the treatment with 25% satiation feeding was lower than the other treatments (p <0.05). Total protein and triglyceride in 100 and 75% treatments were higher than the other treatments (p < 0.05). Based on the present study, feeding, at the rates of 75 and 50% satiation and subsequent re-feeding lead to a high growth rate and reducing the feed costs without negative impact on physiological conditions of the great sturgeon fish, and this methods can be considered as an appropriate strategy for culture of this fish.

The purpose of this study was to investigate the effects of using two levels of Sanyar prebiotics (powder and liquid) on growth performance, feed productivity, digestive enzyme activity and non-specific immunity of Cyprinus carpio juveniles in the biofloc system. Common carp (10.09 ± 0.45 g) were stocked into 18 tanks (35 L) in six treatments for 60 days, including: Control treatment without additive and with clean water (C), Control treatments without additive with Floc (FC), Floc treatments with 0.1 and 0.2 g (FP1 and FP2) powder prebiotic and Floc treatments with 1 and 2 ml (FL1 and FL2) liquid prebiotic per 100 g of basic diet. Water parameters are maintained at the standard level for this species. Total ammonia concentration (TAN) was statistically significant between experimental treatments. The growth of fish was obtained significantly higher and the feed conversion ratio was lower in FP1. The highest intestinal protease activity (8.42± 0.05) was obtained in FP1 treatment. The lowest serum cortisol and glucose were observed in FP1. The immunoglobulin and lysozyme serum in FP2 and FL1 were significantly higher than other treatments. The results of this study showed that the use of 0.1 g of Sanyar prebiotic powder per 100 g of basic diet in the biofloc system could improve growth performance, and the immune status of C. carpio.

Behavior of fish consumers in rural households in coastal areas of Golestan province after designing a questionnaire and collecting data, statistical analysis was performed in 2020. In inferential analysis of the research, chi-square, Mann-Whitney and scoring methods were used for ranking. They per capita consumption was 14 cans and their per capita consumption was 14/7 kg. 64% of them consumed less per capita than the national average (12/1). Rutilus firisii kutum was the most popular species, but they could not afford to buy sturgeon. The reasons for their consumption were quality and freshness, cleanliness and hygiene, and interest in fish, respectively. The income group above 2/5 million Tomans had a per capita consumption increase of about 9 kg compared to the lower group. And in the purchase of fish flavor, taste, size, species, properties and nutritional value and not in danger of extinction and the desired supply of fish, fresh, frozen and canned for them was more important than the other group. All 9 factors examined in households with higher education level than diploma and those with higher per capita consumption than the national average was more important in buying fish. Under the age of 45 in shopping to flavor, taste, properties and nutritional value and in the desired supply mode, more than older ages, they paid attention to filleted and canned fish. Households that had higher per capita consumption than the country's per capita Fish consumption and with university education cared more about fresh, packaged and canned fish than anyone else. Despite the interest in fresh fish and certain species in these areas, access to them seems to be limited and income, educational, age and consumption limits are effective in the tendency to consume fishery products along with fresh fish. And the possibility of providing a market and supply of processed products, helping the economy of rural households in rural areas to increase per capita consumption.