Iranian Scientific Fisheries Journal
Year:2020 | Volume:29 | Issue:6|Papers Count:16

Photoperiod is one of the very important environmental factors that extremely affect growth performance, feeding and reproduction of various fish species. Thus In this research effects of different photoperiod regimes on Caspian Salmon during the premature stage (18 months old at the beginning of experiment) were investigated. One thousand liter tank with 20 premature fishs were allocated for each treatment. Applied photoperiod regimes during 6 months experimental period were: (1) continues light (24L/0D), (2) 18L/6D during first three months and 6L/18D during second three months, (3) 6L/18D during first three months and 18L/6D during second three months and (4) continues dark (0L/24D). Results indicated that growth performance, feeding and reproduction were influenced by the photoperiod regimes. The highest values of SGR (0. 44 % d-) and the lowest values of FCR (4/3) were observed in treatment 4 that showed significant differences as compared with treatment 1 (0. 35 % d- and 4. 4) treatment 2 (0. 33 % d- and 4. 7) and treatment 3 (0. 34 % d- and 4. 5). Maturation of females was not influenced by experimental photoperiod regimes but maturation of males was significantly influenced. As all males of treatment 2 reached sexual maturity at the end of experiment. In contrast, treatments 3 and 4 postponed gonad development and maturation of males. Therefore, to increase the growth of Caspian salmon, the 24-hour dark photoperiod and to stimulate its sexual maturation, the 18 and 6-hour light photpperiod is recomonded in the first and second trimesters of the six-month photpperiod regime, respectively.

This study was carried out to determine the effect of raibow trout cage culture on the abiotic factors of water in the Abbas Abad area, southern basin of the Caspian Sea. For this purpose, water samples were collected at distances of 5, 50, 100 and 1000 m from the cage culture during December 2014 to August 2015. Based on the results, it was shown that the mean value of water temperature for surface layer varied between 12. 2 and 30. 16 ° C from December to August. The highest and lowest mean value of salinity obtained in August (11. 26 g/l) and April (10. 66 g/l) respectively. The range of pH value changes (8. 36-8. 83) was as small as the rate of electro conductivity variations (18. 11-19. 07 µ s/cm). The highest concentration of dissolved oxygen was observed in December at 1000 m station (9. 23 mg/l) and the lowest was seen in April at 5 m station (7. 27 mg/l). Also the mean values of Total Dissolved Solids, Turbidity, Nitrite, Nitrate, ammonium, Total Nitrogen, Phosphate and Total Phosphorus was obtained 9. 59 (g/l), 5. 55 (NTU), 3. 67, 133. 45, 92. 6, 929. 72, 21. 63, 37. 73 (µ g/l) respectively. The results of abiotic factors of water showed that most of the measured parameters had significant differences only among different sampling periods (p<0. 05) whilst, for some factors such as dissolved oxygen, ion ammonium and phosphate, there were significant differences between different stations (The effect of distance from the cage) at each sampling period as well as (p<0. 05). It seems that the cage culture of rainbow trout in the Abbas Abad area had only a minor impact on measured factors probably due to low stocking density, short-term of fish farm and high current velocity.

In the present study, the antioxidant activity of different concentrations of protein hydrolysate from Common carp (Cyprinus carpio) head at different hydrolysis time was investigated. For this purpose, 8 Common carp fish with average weight of 0. 766± 0. 034 kg were prepared from market. Fish heads were hydrolyzed by Alcalase (1% v/w at 55˚ C and pH 8) at different hydrolysis times (30, 60, 120 and 180 min). The result of proximate analysis showed that the protein content increased significantly (from 58. 31± 1. 9 to 75. 26± 1. 49%) as a result of hydrolysis, while the amount of fat and ash decreased significantly (from 16. 46± 0. 87 to 2. 37± 0. 97%; from 27. 16± 0. 64 to 25. 34± 1. 63%, respectively, p<0. 05). Also, as the duration of hydrolysis increased, the amount of soluble protein and the degree of hydrolysis increased significantly, so that the highest soluble protein 23. 01± 0. 19 mg/ml and the highest degree of hydrolysis 49. 67± 0. 86% were obtained at the time of 180 min. DPPH radical scavenging activity of protein hydrolysate showed significant increasing trend at different hydrolysis times and different concentrations (p<0. 05). The optimum time for DPPH radical scavenging activity (DPPH) was determined at 180 min and IC50 value was obtained 2. 08 mg/ml. In addition, with increasing concentration and duration of hydrolysis, the ferric ion reduction power and ABTS radical scavenging activity increased significantly (p<0. 05). In general, due to the proper activity of different concentrations of Common carp head protein hydrolysate on DPPH and ABTS radicals scavenging and reduction of ferric ion, it can be stated that this protein hydrolysate can be considered as a dietary supplement with desirable antioxidant function.

This study was conducted to evaluate the effect of different concentrations of selenium and zinc nanoparticles on growth performance, survival and chemical composition of Whiteleg shrimp (Litopenaeus vannamei). For this purpose, shrimp with an average weight of 5. 1± 0. 2 g were distributed in 12 fiberglass tanks with 25 shrimp density and were fed for 56 days with different concentrations of selenium and zinc nanoparticles in four groups with three replicate including 0 (control), T1 (0. 3 mg/kg of selenium nanoparticl), T2 (0. 15 mg/kg of selenium nanoparticle+ 15 mg/kg of zinc nanoparticl) and T3 ( 30 mg/kg of zinc nanoparticl). Based on these results, weight gain increasing, specific growth rate and feed conversion ratio in T2 treatment compare to T1, T3 and control treatments (p<0. 05). Also, there is significant differences in survival rate between T1 and T2 treatments compared to T3 and control (p<0. 05). Statistical analysis showed that there was a significant difference in protein and lipid carcass percentage between shrimp-fed diets containing different levels of selenium and zinc nanoparticles compared to control treatment. In general, the effect of different concentrations of selenium and zinc nanoparticles, especially in the T2 on growth performance, survival and chemical composition was positively and significantly evaluated.

In this study, pharmacological properties of three native macro algae which collected from the shores of the Chabahar Gulf (the Omean Sea) including: Ulva lactuca, Sargassum ilicifolium and Nizimuddinia zanardini were evaluated. The methanol extracts of three species of green, brown and red algae were. The concentration of β-carotenoid, phenolic Compound and antioxidant activities (AOA) was analyzed by routine methods. Based on the results, different antioxidant properties were observed among algae. These results probably was associated with antioxidant compounds of algae. In the species of U. lactuca, S. ilicifolium and N. zanardini the amount of β-carotenoid was measured 0. 56, 0. 048 and 0. 041 mg/100DW, total phenol was 0. 206, 0. 396 and 0. 133 mg GA/g DW and inhibitory activity of free radicals (DPPH) was in the range of 45. 7-60. 4%, 51. 6-61. 8% and 9. 6-28%, respectively (p<0. 05). Based on obtaining results, the highest level of β-carotenoid was observed in the U. lactuca extract and the highest level of total phenol and inhibitory activity of free radicals (DPPH) was observed in S. ilicifolium extract. Overall, the results of this study indicated that all three species of algae have usability as a primary substance in food and drug industry.

Genetic variability of longspine scraper populations from the Choman, Shui, Garmab (Baneh region), Gheshlagh, Sirvan, Gaveh-Rud (Sirvan region), Rowar (Marivan region) of Kurdistan province were examined using Inter-Retrotransposon Amplified Polymorphism markers (IRAP) method. IRAP molecular markers data analysis showed the highest and the lowest number of bands, polymorphic bands, percent of polymorphic bands, number of different bands, number of private bands, number of effective bands, Shannon's information index and expected heterozygosity in the Rowar and the Garmab populations, respectively. The highest and the lowest genetic distance was observed between the Rowar and the Shui populations and between the Choman and the Garmab populations, respectively. The molecular variance analysis results revealed that 9% of genetic variance was between geographic regions, 16% among and 75% within the populations. The highest and lowest gene flow rates (number of migrations per generation) were observed among the Choman, Garmab, Rowar and Shui populations, respectively. Phylogentic relationships of the populations were evaluated using the maximum parsimony methods. Phylogenetic analysis showed that the Marivan region is in a sister clade with the regions of Baneh and Sirvan. The results of this study showed that although the longspine scraper population of Marivan region was different from other populations, the existence of similarities prevents its complete separation. However, fish belonging to each population of the studied geographical areas can be distinguished by their private bands. The results of this research showed that the IRAP marker has high reproducibility and greater power in detecting genetic diversity and can be used effectively to study the genetic diversity of fish, including the longspine scraper species.

The present study aimed to identify, introduce and compare pseudoparasites in wild fish (Rutilus kutum and Mugilidae) and cage culture rainbow trout (Oncorhynchus mykiss) in the southern coast of the Caspian Sea. Wild fish specimens were collected from four stations in Anzali, Kiashahr, Chalus, Mahmoudabad and rainbow trout in three cages of Kiashahr, Abbas abad and Si-Sangan. After transferring the specimens to the laboratory, they were bioassayed and parasitological examination was performed on all internal and external organs. Freeliving nematodes, pine pollen, pollen grain, protozoa, fungal spores, plant seeds, and filaments were isolated from fish as pseudoparasites. The highest percentage of pseudoparasites belonged to Pine pollen and was found in almost all fish organs. Free-living nematodes were isolated from the stomach, intestine, gills and Pollen grain from the liver, spleen, and kidneys of fish. Pseudoparasites are widespread in addition to they may be transmitted by food or randomly to fish. Pseudoparasites do not cause infection and disease in their host. Investigating and understanding them because of their importance in the parasitology can be useful for parasitologists and fish farmers to avoid the futile consumption of pharmaceuticals.

Water quality assessment using water quality indices and biotic indices is a group of suitable methods. This study was carried out to determine temporal and spatial variations of benthos in Pasikhan River, north of Iran. Therefore, 6 sampling stations were set up along the river mainstream and the macrobenthic invertebrate community samples were collected from these stations during 4 seasons (from autumn 2015 to summer 2016), seasonally. The benthos samples were collected by surber sampler (25×25 cm) in sixteen replicates, then were identified and counted. The results of the benthic communities of Pasikhan River showed the dominant taxa of the invertebrates collected belonged to aquatic insects group. In this study, 18 families of 9 orders of benthic macroinvertebrates were identified. BMWP index at sixth station, showed the lowest annual average score (5. 50± 2. 38) with so bad quality and the second station, showed the highest average score (41. 00± 16. 39) with medium quality. Also, according to the annual average ASPT, second station had the highest score (5. 83± 0. 38), and showed suspected to water pollution. The sixth station with the lowest score (2. 50± 0. 91) was classified in high pollution group. Among the seasons, the highest and the lowest amount of both BMWP and ASPT were observed in winter and autumn, respectively. The results of Hilsenhoff index between stations showed that first station with average score (5. 26± 1. 10) was categorized in medium class and fourth station with average score (4. 58± 0. 56) was categorized in good class. This could be due to sand mining before first station (Bodab Bridge). Based on the results, biotic indices showed that water quality in Nokhale station (Station 6) that is located in downstream is the lowest that may be due to anthropogenic activities, discharge of domestic wastewater and agricultural runoff and sand mining.

The present study investigated the cultivation of Dunaliella viridis microalgae in the stickwater (SW) from the wastewater of fishmeal factories. For this purpose, Gillard culture medium (F/2) was used as a control treatment and five different levels of SW including 10, 25, 50, 75, and 100% were used. Then, these microalgae were cultured in 8-liter plastic containers for 14 days to evaluate the algal density and pigment contents (chlorophyll a and total carotenoids). The results of the present study showed that by increasing in the concentration of SW up to 75% the cell density was increased. In addition, the pigment contents were significantly affected by SW concentrations and the highest amount of chlorophyll a was observed at a concentration of 75% SW compared to other treatments (p<0. 05). Also, the highest amount of carotenoids was recorded simultaneously in 75% and 50% SW treatments compared to other treatments (p<0. 05). According to the obtained results, using SW at 75% is feasible to grow D. viridis microalgae.

Today, microalgae are considered as an important source for the production of biofuels and pharmaceutical products. However, the lack of an efficient and economical method for dewatering and harvesting their biomass is is an important challenge to achieve this goal. The important issue for choosing the harvesting method are species characteristics, final product value and energy consumption. Therefore, in this study, the effect of flocculation method with pH change technique (range 6 to 11) using sodium hydroxide and hydrogen chloride on harvesting efficiency, and fatty acid content of Dunaliella salina was tested. The results of this study showed that with the addition of sodium hydroxide and increasing the pH from 8. 2 to 9. 8, the flocculation process increased upwards from 18 to 90% and then remained constant until: pH 11. In contrast, increasing hydrogen chloride and creating an acidic environment up to: pH equal to 6 had no effect on clot stimulation. The highest coefficient of biomass concentration was observed in alkaline treatment with pH: equivalent to 9. 8 which was 10 times the initial concentration (at pH equal to 8. 2 the effect of alkaline pH induction technique and the centrifuge technique on the fatty acids content of biomass was tested. In the next stage, the effect of alkaline pH induction technique and the centrifuge technique on the fatty acids content of biomass was tested. The analysis showed that the percentage of lipid and fatty acids of harvested biomass were significantly different from each other. Based on the obtained results, the flocculation method by increasing the pH by 9. 8 is a simple and relatively inexpensive technique with high efficiency and is suitable for harvesting Dunaliella salina microalgae for specific purposes.

One of the methods of standardization of gill nets is to determine the appropriate mesh size for each species. The purpose of this study was to determine. This study was aimed to determine the suitable mesh size of drift gillnets for catching skipjack (Katsuwonus pelamis). The sampling operation was carried out by the lange boat in the spring of 1397. The fishing tool consisted of drift gillnet for Skipjack tuna with a stretched mesh size of 160 mm. Fork length and body length were measured in two areas of skipjack tuna body. The total numbers of 394 specimens were measured, the fork length range was 38 to 77 cm with mean and standard deviation of 55. 02 55 ± 5. 90 cm. The highest frequency of Skipjack was in the range of 48-58 cm with 77%. The equations of linear relations between fork length and gill circumference: Gop = 0. 577 FL + 1. 866 with coefficient of determination 0. 926 and linear relation for fork length and body circumference Gmax = 0. 922 FL – 9. 750 with a Coefficient of Determination 0. 963 were gained. The elongation rate was 17% for gill circumference and 21% for the body circumference. In general, based on the present study, a drift gillnet with a mesh size of 136 mm can be used to capture Skipjack, which is slightly smaller than the minimum mesh size used by fishermen.

Determination of the sub-lethal effects of diazinon toxin carried out on steroidogenesis and quality of sexual production in male goldfish breeders. For this purpose, fish were first exposed to different lethal concentrations of diazinon toxin (9, 10, 11, 12. 5, 15 and 20 mg/L) and LC50 values were analyzed for 96 h using probit software. The amount of LC50 was 11. 4 in 96 hours and fish were assorted according to 0, 0. 25, 0. 50 and 0. 75 percent of LC50 in 96 hours and were put there for 2 months. At the end of the experiment, the level of sex hormones and the quality of sexual production were studied in male broodstock. The results showed that diazinon toxin significantly reduced testosterone and 17-β-estradiol levels in the 0. 50 and 0. 75 mg/L treatments compared to the control (p<0. 05). There was no significant difference in some sperm quality parameters such as sperm volume, sperm density and spermatocrit between the control and 0. 25 treatment. By increasing the concentration of diazinon toxin (from 0. 25 to 0. 75 %), the duration of sperm motility decreased significantly. The percentage of motile sperm in the control treatment was higher than other treatment and it was decreased with increasing diazinon toxin concentration. The Gonadosomatic Index in the control treatment was significantly higher than the other treatments (p<0. 05) and showed a decreasing trend with increasing toxicity. In conclusion, diazinon toxin in the aquatic environment, even at sub-lethal concentrations, causes undesirable changes in the sex steroid indices and quality of male gonads in goldfish.

In order to analyze the socio-economic of the fish market, a questionnaire was designed through interviews with experts and searching for scientific sources. In 2019, the questionnaire was then collected for 72 fishmonger Golestan province. According to Kolmogorov-Smirnov test and nonparametric data, Kruskal-Wallis and Mann-Whitney U tests were used to analyze and compare independent and dependent factors. In addition, the profitability and per capita of each economic factor were calculated. To prioritize problems from the Friedman test and linear regression was used to assess the social characteristics of sellers. The average annual sales per fishmonger were 23/3 million tomans, which is about 60 percent profitable. Only 36 percent of the provinces had fish store. Fishmonger's per capita income is about 22 million and their profit per capita is 13/5 million tomans. On average they sell at least 45 kg and 528 kg daily. The most important problems in the fish market are the reduce customers' purchasing power, high competition, low marine reserves and low and unsuitable space. Fishmonger with over 15 years of experience, high competition and low marine reserves, and fish retailer heavy rent and tax as knew the most important market problem for the other group. In contrast, wholesalers saw low of marine reserves and the increase in illegal fishing as a major problem. Sellers under 35 years were also more upset about the lack of capital and heavy rents. Shops with more than 15 years of experience earn 39/1 million tomans a year and higher education than the retailers' diplomas generate 33/47 tons more than the other group. Therefore, market regulation by encouraging the launch of fish shops in non-market towns as well as helping to increase the income of Golestan citizens can be effective in boosting sales and consequently the consumption of fish.

The quality of fish flesh is affected by several factors including slaughtering methods and preslaughter conditions. In this study the effect of main operational variables such as fasting time ( ), density ( ) and fish weight ( ) in the TBA value of common carp fillet has been evaluated and analyzed using the response surface method and Box-Behnken model. A numerical optimization model was performed to obtain the minimum amount of TBA in the fillets. Adapted fish treated by fasting time, density and weight and then harvested after 1, 4 and 7 days, slaughtered by smothering out of the water and then fillet. The results showed that the lowest TBA value on the second-order model was obtained at a low level of (4 fish numbers), low level of (500 g) and high levels of (7 days fasting time). The optimal TBA value was determined 0. 6842 by a model which was measured 0. 701 after the practical validation test in the optimal condition which indicating the high accuracy of the model to determine the optimum pre-slaughter. Therefore, the results of this study showed that using the response surface method is appropriate to optimize pre-slaughter conditions of common carp and also the second-order model can be used to predict the response variable in different conditions of pre-slaughter.

Alginate is one of the unique polysaccharides present in brown algae which are widely used in textile, paper, and food, pharmaceutical, biomedical and cosmetic industries. There are many seaweed species in the southern coast of our country (Iran). However, very few studies have been done so far on the extraction of alginate from these indigenous resources. Therefore, in the present study, alginate was extracted and purified from a brown seaweed Sargassum ilicifolium. Then, yield, molecular weight, antioxidant activity (DPPH radical scavenging activity and reducing power (FRAP), and emulsifying properties (emulsification indices) of the isolated alginate were evaluated. Furthermore, FT-IR spectra were used to identify the functional groups of the extracted alginate. Alginate extraction yield was 20. 84± 1. 24% (based on seaweed dry weight). FT-IR results showed that the extracted polysaccharide was mainly sodium alginate. The molecular weight of the extracted alginate was 1865 kDa. The DPPH radical scavenging activity and the reducing power of the extracted alginate at 1 mg/ml were 18. 17± 2. 03% and 0. 155± 0. 004 (Abs), respectively. The extracted alginate was able to emulsify sunflower, corn, and canola oils. The highest and lowest emulsification indices (E24) were observed in sunflower and canola oils, respectively. Overall, the results of the present study showed that the alginate extracted from S. ilicifolium has medium antioxidant and high emulsifying properties.

Considering shrimp farming is as an improving aquaculture practice in southern and northern coastal parts of Iran, it faces some critical and challenging problems in terms of water quality that need to be monitored. The present study purposed to assess the water quality and total organic matter (TOM) in sediment of Litopenaeus vannamei shrimp farms during the culturing period from July 2014 in Teyab shrimp farms, Hormozgan, Iran. The results indicated that during the culturing period, mean values for temperature, salinity, pH and dissolved oxygen were not significantly different in 3 farms, whereas the levels for total organic matter showed the highest content onwards to the end of culturing period. The results showed positive correlation was found between pH and water temperature, pH and dissolve oxygen (DO), pH and ammonia. However a negative correlation was observed between TOM and pH, TOM and water temperature, TOM and ammonia. Dendrogram of temporal clustering results showed that the water quality was relatively consistent during early culturing period and then represent an unstable condition from the second month towards end of culturing period. However, water quality parameters should be monitored to serve as guide for managing a pond so that conditions that can adversely affect the growth of prawns can be avoided.