مجله علمی شیلات ایران
سال بیست و نهم شماره 5 (پیاپی 121، آذر و دی 1399)

The purpose of breeding is to improve the quantity and quality of the desired characteristics in cultured species in the next generations. Individual selection is a simple and practical way to provide a quick response in improving high heritability traits for breeding most species in aquaculture. At first step, in Yasouj cold water fishes breeding research Center, in order to conducting selection program in rainbow trout brood stock as base population and improving food conversion ratio (FCR) in  their offsprings, 150 female and male broods with higher mean weight were  selected, striped in 6 stage and eggs were incubated. One-year produced Fish (45000 pcs.) of the six groups with higher mean weight  in 5 stage were selected (438 pcs.) and remainder was discarded. Before selection, a few fish of six aged-groups as control group were cultured apart. Significant difference (p<0.05) induced between final mean weight of some groups (the selected groups and control group) and significant difference (p<0.05) between mean weight of the control group (717±96 g.) and the selected groups (1007±136 g.) can be a result of genetic improvement of growth rate trait induced of selection process in one generation and most likely because of age difference in them and because of no selection and deletion in control group (don’t throw out small individuals). There were no  significant difference (p>0.05) between FCR of six aged-groups (1.56±  0.16) and control group (1.53±  0.07). The lack of disclosure or promotion of FCR of most of the groups under selection program compared to the control group indicates that the effect of this selection method on the genetic improvement of FCR in one generation is indiscernible and to reveal the improvement of this trait, continuing the selection program to promote growth rate over several generations and, consequently, improve FCR is necessary.

The current study aimed to determine the isotopic composition of different food sources and their contribution to the diet of Parasesarma persicum inhibiting a mangrove ecosystem in the Persian Gulf. The potential food sources, i.e., Avicennia marina green and yellow leaves, Particulate Organic Matter (POM), Microphytobenthos (MPB), and Sediment Organic Matter (SOM) were collected for stable isotope analysis. The most 13C-depleted values were observed for mangroves with mean δ13C values of -28.31‰ and -28.05‰ for green and yellow leaves, respectively. The mean δ15N values of mangrove leaves were 3.79‰ and 5.08‰ for green and yellow leaves, respectively. The crab P. persicum had an average value of carbon and nitrogen isotopes of -19.48‰, and 4.18, respectively. The results showed that the A. marina yellow leaves (28.1%) and SOM (13.3%) had the highest and lowest contribution to the diet of P. persicum in the mangrove ecosystem, respectively. The results emphasize the role of mangroves in supporting estuarine food webs. This also further confirms the ecological role of sesarmid crabs as ecosystem engineers in mangrove ecosystems.

The present study was conducted to evaluate the effect of different levels of Aphanothece halophytica microalgae on the fatty acids and amino acids composition of Artemia urmiana nauplius for 3 weeks. Cysts were hatched under identical standard conditions and the experiment was conducted in a completely randomized design with 1200000 of nauplius in 3 trial treatments and 3 replicates (n=100000 in each replicate) included: with 200 mL microalgae with 22 × 106, 16× 106 and 13× 106 cell/mL respectively and control group (1g yeast per 10000 nauplius).The results showed that at the end of experiment, the highest EPA (3.99± 0.25%) and DHA (1.44±0.02 %) was showed in treatments fed with 13× 106 cell/mL. Also, the highest Asp, Gli, Ser, Gly, His, Arg, Thr, Ala, Tyr, Val, Met, Ile, Leu and AA was shown in treatments fed with 13× 106 cell/mL which  showed significant difference compared to other treatments (P<0.05) Overall, the results of the present study revealed that A. urmiana nauplius fed with different levels of A. halophytica microalgae showed better fatty acid and amino acid composition than to control group, and use of 13× 106 cell/mL A. halophytica algae could suggest for A. urmiana nauplius.

In the present study, quality and shelf-life of anchovy (Encrasicholina punctifer) during 12 days of iced storage (+1 to -1 ˚C) were investigated by using of sensory, chemical and microbial indices. For sensory assessment, internal organs, gill, peritoneum, skin, eyes, color along spine, abdominal cavity and flesh of samples were assessed. For chemical assessment, indices of pH, total volatile base of nitrogen (TVB-N), free fatty acids (FFA), peroxide value (PV) and thiobarbituric acid (TBA) were measured. Microbial analysis was done by counting the colonies of bacteria during the storage period. Sensory analysis showed that the shelf-life of the anchovy was between 7 to 9 days. Total counts of bacteria exceeded the acceptable limit (106 colonies per gram of meat) on the 8th day of storage. A high correlation (0.96) observed between sensory and microbial results. The pH of fish increased from 6.27 to 7.56 at the end of storage. Total volatile base of nitrogen (TVB-N) of fresh anchovy at the first day of storage was 8/67 mg N/100 g meat and reached to 36.65 at Day 12 of survey.  The changes of free fatty acids were in the range of 3.63-8.60 % of oleic acid (p<0.05). Peroxide value (milli-equivalents active oxygen per kg lipid) significantly increased from 11.37 at the beginning to 30.96 at the last day of storage (p<0.05). The amount of thiobarbituric acid (milligrams of malondialdehyde per kg of meat) increased from 0.35 at Day 0 to 5.16 at Day 12. The shelf-life of anchovy days during iced storage estimated between 7-9 based on the sensory, microbial and chemical results.

Kurdistan province is one of the most important provinces in Iran in terms of surface and underground waters, and the Garan resevior (Marivan) has important rules in aquaculture and fisheries activities. For this purpose, the present study was carried out including a survey of 22 physico-chemical parameters at four sites of Garan reservoir from July 2017 to August 2018. Results showed that the mean value of water temperature 11.13 ± 6.7 °C and the Dissolved Oxygen (DO) concentration was 8.44 and 3.87 mg/l for surface and deep layers respectively. Based on the results, was shown that the Thermocline and oxycline start from June and they vanish in December as well as. Mean of pH value 7.99 and secchi disc depth was high (2.3 m) relatively. Also the mean value of alkalinity, Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Dissolved Solids (TDS) and electro conductivity 138.59, 1.32, 25.02, 0.047, 156.91 mg/l and 242.18 (µmhos/cm) respectively. Also mean of nutrients were within desirable limits. In general, although seasonal and spatial variations were observed in some parameters, but according to the results of physico-chemical characteristics, the Garan reservoir could be considering suitable for standard pattern of aquaculture activities.

One of the major objectives in the modern and sustainable aquaculture industry is to increase the feed efficiency and survival rate. The present study is aimed to investigate the effect of paprika powder on some growth performance and immunological parameters in zebrafish for a period of 56 days. In this study, a total of 480 zebrafish fry (initial weight of 0.05g and length of 1.71 mm) were randomly divided into 12 tanks and fed with 0 (control), 1, 2, and 3 g of paprika powder per 100 gram of feed. The results of the growth indices and survival rate indicated that the highest weight gain (0.42±0.02 g) and body weight increase (0.36±0.03 g) was observed in 3% of paprika powder (P<0.05).Immunological serum parameters including lysozyme, IgM, complement components (C3 and C4) which represented significant differences in comparison with the control group (P<0.05). The highest activity level of lysozyme was observed in 3% of paprika powder and the highest levels of C3 and IgM were measured in both 2% and 3% of paprika powder. Moreover, addition of paprika powder at different levels without any significant differences between the treatments increased C4 level compared to the control group (P<0.05). On the whole, dietary supplementation of paprika powder in zebrafish feed at the level of 3% led to the improvement of the growth performance as well as immunity modulation and probably can act as an immunostimulant.

We studied the accumulation of heavy metals (Zn, Cd, Ni and Pb) in muscle tissue of Whiteleg shrimp (Litopenaeus vannamei) sampled from shrimp farms in the Sistan Baluchistan, Iran. Sampling were conducted in April to June 2018 at three-time points of 35, 65 and 95 days after stocking in ponds randomly with three replications from two farms and two pools. After biometry, muscle tissue was isolated and the amount of metal accumulation was measured using flame atomic absorption apparatus. Results showed that the mean length (cm) and weight (g) were 6.15±0.65 and 4±0.8 in 35 days after stocking,10.63±0.73 and 9.61±1.63 in 65 days after stocking and 12.33 ± 0.51 and 16.04±1.33 in 95 days after stocking. The results showed a significant difference between the concentrations of zinc, cadmium, nickel and lead in sampling pools (p<0.05).The results did not show a significant difference between the pools at each time interval (p>0.05).The trend in heavy metal accumulation muscle tissue was increasing after stocking. The mean concentration of metals was 11.52±0.42 for copper, 82.95±6.65 for zinc, 3.54±0.47 for cadmium, 2.18±0.31 for nickel and 1.85±0.19 for lead (μg/g dry weight).  With the exception of nickel, which was  near the WHO standard, other metals were lower than the standard values reported by International Food and Drug Administration (FDA) and the World Health Organization (WHO).

Caspian sturgeon is one of the most important and economically valuable fish that unfortunately have witnessed a sharp decline in their natural stocks in recent decades, as they are on the endangered species list. Therefore, given the importance of sturgeon, identifying the factors that reduce their stockpiling is essential. The present study was applied in terms of purpose type and descriptive-analytical and survey method. The sample size was estimated based on Cochran formula of 270 fishermen by available and voluntary sampling method and the required information was collected by distributing questionnaires based on Likert spectrum and in-person interviews among fishermen in Golestan, Mazandaran and Guilan provinces. Questionnaire data analysis was performed using structural equations and PLS software and the findings indicated that factors such as overfishing, low release rate, illegal fishing, ؛ Inadequate fishing management ؛ Non-standard fishing gears and equipment had a significant and positive impact on the Reduction of sturgeon stocks , with the largest impact being illegal fishing. However, the effect of contaminant inflow and water pollution had a positive effect on the downward trend of sturgeon stocks, but was not significant. The findings of the present study can be of great help to fisheries decision makers in planning and Their implementing measures to restore sturgeon stocks their reserves and prevent their rapid decline and lead to improved sturgeon restoration efforts.

The present study aimed to investigate the effect of the commercial probiotic BetaPlus® Ultra (BP Ultra) in combination with the galacto-oligosaccharide (GOS) or the isomalto-oligosaccharide (IMO) prebiotics in Caspian trout (Salmo caspius) parr. S. caspius (8.5±0.07 g) was randomly distributed in three dietary treatments including: control group, synbiotic treatment I (0.1% BP Ultra + 0.2% GOS) and synbiotic treatment II (0.1% BP Ultra + 0.2% IMO) and in nine 300 L circular polyethylene tanks with three replications per treatment and, then, fed for seven weeks. At the end of this experiment, growth performance and hepatosomatic index improved significantly in both synbiotic treatments compared to the control group (p<0.05). However, the trend of this improvement was more noticeable in the synbiotic treatment I compared to the synbiotic treatment II without any significant difference (p>0.05). The counts of red and white blood cells in the both synbiotic treatments were significantly decreased and increased compared to the control group, respectively (P<0.05). The values of hemoglobin, packed cell volume, and mean corpuscular hemoglobin in the synbiotic treatment I showed significant increases compared to the synbiotic treatment II (P<0.05). The highest significant levels of crude protein and lipid in carcass were observed in the synbiotic treatment II and the synbiotic treatment I, respectively (P<0.05). Dry matter of carcass was increased significantly in the synbiotic treatment I compared to the synbiotic treatment II (P<0.05). The lowest ash content of carcass was observed in the synbiotic treatment I with a significant difference compared to the synbiotic treatment II and the control group (P<0.05). The results of the present study demonstrated the remarkable efficiency of the synbiotic treatment II on the protein increase and lipid reduction in carcass, although the synbiotic treatment I had a better effect on growth performance and hematological parameters in S. caspius.

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.

The rate of overfishing of Black pomfret (Parastromateus niger) in the southern waters (1997-2018) was performed based on CMSY model, R software, Bayesian status approach (Problem solving based on basic information) and Monte Carlo simulation. The average catch of this species was 5570 tons with a 95% confidence interval of 4145 to 6994 tons and the average catch increased significantly during the last two decades in the Southern Waters  (R = 0.86, P <0.05). The catch of this species in the southern waters has increased from about 2500 tons in 1997 to about 12500 tons in 2018 and Sistan and Baluchestan province has the highest trend of Black pomfret fish catch in the Persian Gulf and Oman Sea. Considering the rate of overfishing (total weight) of Black pomfret fish in the southern waters, the catch status of this species has changed from low (green color) in 2008 to medium catch (yellow color) in 2018. The overfishing rate of this species in Bushehr province is red color. It seems, in order to maintain sustainable yield, fishing effort rate and catch rate in the southern waters, especially in Khuzestan and Bushehr provinces, should be reduced.

Rainbow trout filet is a high nutritive value product that can be introduced to consumers successfully which have short shelf life. In this study, the effects of Nano-capsulated chitosan analyzed with and without sodium acetate coatings on increasing the shelf life of refrigerated Rainbow trout filets (Onchorynchus mykiss) during refrigerator storage (4±1°C) and in polyethylene with zipper bag during 16 days. For this purpose, the Rainbow trout filets were immersed in five treatments that included: solutions of NCH1%, NCH2%, NCH1%+NaOAC1.5%, NCH2%+ NaOAC1.5% and distilled water solution as a control sample. The antimicrobial effect of Nano-capsulated chitosan coating with and without sodium acetate was evaluated by counting of aerobic mesophilic bacteria, lactic, psychrophilic bacteria and chemical properties including pH, TBA, PV and TVB-N. Sensory evaluation determined by 5 evaluator persons who were asked to evaluate the flavor, odor, color, texture and overall acceptability of samples in days 0, 3, 6, 10, 12. Sensorial, chemical and microbial results evaluated by ANOVA and Duncan tests. Sensorial, chemical and microbial results showed that in end of storage Nano-capsulated chitosan with and without sodium acetate 1.5% were better significantly compared to control group (p<0.05). In this study, the sample contained NCH2%+ NaOAC1.5% coating treatment showed the best results of storage. The results of Sensorial, chemical and microbial tests of Nano-capsulated chitosan and Nano-capsulated chitosan with sodium acetate indicted that shelf life storage were increased from 6 days in control treatment to 12 and 16 days, respectively.

Golden grey mullet (Chelon auratus) is one of the most important commercial species of the Caspian Sea. Considering its economic importance, some characteristics population dynamics indices  catching status were studied in south-east of Caspian Sea (Golestan coasts). In this study, 886 speciements were collected and became biometrics during the period of 2014-2015.  Speciemens were range fork length 20-52 cm and 125-1235 g and most frequency (11.2%) belong to 29-30 cm groups. Infinity length (L∞) and growth coefficient (k) were estimated 54.08 cm and 0.34 year-1, repectively. The relationship between length and weight, the value of b was 2.8368, indicating a negative allometric growth model. Total mortality, natural, fishing and exploration rates were calculated 1.13, 0.58, 0.55, and 0.49 year -1, respectively. Its biomass and maximum sustainable of yield  (MSY) were estimated 994749 kg and 305824 kg, respectively in 2016, while catch ration was 330770 kg in Golestan coasts. Thus it was 8% overfishing from permitted limit. Overall, regardness the maximum allowable catch is essential for sustainable management and conservation of stocks.

Primary production is an important component in the biological cycle in terms of carbon storage and a key indicator for evaluating of ecosystem function. In this study, net primary production and its components were investigated in the coastal zone of Iranian basin of Caspian Sea during four seasons from 2018 to 2019. In addition, the effective environmental factors on spatial-temporal distributions of net primary production have been studied. As a results, mean (±SD) of Chl-a, euphotic depth (Zeu), active photosynthetic radiation (PAR), maximum primary production per unit of Chl-a (PBopt) and daily net primary production (DNPP) were obtained 2.54±3.23 mg/m3, 28.9±6.8m, 40.42±16.84 Einstein/m2.day, 5.05±1.11 mgC/mgChl-a.h and 2.04±0.73 gC/m2.day. The value of DNPP in the central region was more than the western and eastern regions. It probably is due to effects of wind and waves turbulent on re-suspension of sediment and decrease of light penetration in water column in the western and eastern regions. The seasonal variation of net primary production was in order: autumn>summer>spring> winter. The significant higher NPP in autumn than other seasons (p< 0.05, ANOVA-test), primarily caused by Chl-a and PBoptic. Based on regression and PCA tests, temporal-spatial changes of DNPP has been significantly affected by the two variables of Chl-a and PBoptic.  In general, the classification of trophic state based on net primary production showed that 52% of the data had trophic states in the range of oligo-mesotroph  and mesotroph (49%) to eutroph (3%) and 48% of the data were in the oligotroph group (mainly in the eastern region).

The present study was conducted to investigate the effect of different levels of astaxanthin pigment on growth indices, feed efficiency and biochemical composition of Oriental river prawn. In this study, 225 prawns with mean weight of 1.40±0.05 g were fed by 5 dietary treatments containing different levels of astaxanthin zero (control), 50, 100, 150 and 200 mg astaxanthin per kg diet for 8 weeks. Results at the end of the experiment showed that the diets containing astaxanthin showed a significant difference with the control treatment (p<0.05). However, hepatosomatic index was not affected by different astaxanthin treatments (p>0.05). The highest weight gain, survival rate and lowest feed conversion ratio were observed in 150 mg astaxanthin per kg diet. Carcass moisture, protein and lipid were significantly different from control treatment (p<0.05) but the ash of experimental treatments had no significant difference with control treatment (p>0.05). The results of this study showed that increased levels of dietary astaxanthin improved the growth and nutritional indices of the Oriental river prawn and adding 150 mg per kg astaxanthin to the diet was suggested to improve the growth performance, feed efficiency and carcass quality of this prawn.

The use of absorbent pads in packaged products caused the quality maintains and increase of marketability. But the nutrients accumulation in the adsorbent pad provides a environment growth for the microorganisms that cause spoilage. Therefore, the use of antimicrobial compounds in the adsorbent pad is essential for controlling the microorganisms growth. The aim of this study was to investigate the effect of absorbent pad containing Zataria multiflora leaf essential oil on chemical and microbial properties of Hypophthalmichthys molitrix fillet during storage in refrigerator. 10 ml of Zataria multiflora leaf essential oil 1.5 % were added to pad and fish fillets in different treatments, then packed and stored in a refrigerator (4˚C). The chemical (pH, Peroxide value (PV), thiobarbituric acid (TBA) and total volatile base nitrogen (TVB-N)) and microbial parameters (total viable count (TVC) and psychrotrophic count (PTC)) were measured on days 0, 3, 6, 9, 12 and 15. A significant difference (P <0.05) was observed between the pH of the treatments containing the essential oil and the control in the last days of storage. The results showed that the PV, TBA and TVB-N values of treatments increased during storage. So that the least increase was observed in the fillet containing essential oil, pad containing essential oil and control respectively. The TVC and PTC count of treatments significantly increased during storage (P <0.05). But this increase was less in the fillets containing essential oil than the other treatments. According to the results of this study, it can be concluded that the absorbent pad containing Zataria multiflora leaf essential oil cause the quality preservation and shelflife increase of Hypophthalmichthys molitrix fillet during refrigerated storage.The use of absorbent pads in packaged products caused the quality maintains and increase of marketability. But the nutrients accumulation in the adsorbent pad provides a environment growth for the microorganisms that cause spoilage. Therefore, the use of antimicrobial compounds in the adsorbent pad is essential for controlling the microorganisms growth. The aim of this study was to investigate the effect of absorbent pad containing Zataria multiflora leaf essential oil on chemical and microbial properties of Hypophthalmichthys molitrix fillet during storage in refrigerator. 10 ml of Zataria multiflora leaf essential oil 1.5 % were added to pad and fish fillets in different treatments, then packed and stored in a refrigerator (4˚C). The chemical (pH, Peroxide value (PV), thiobarbituric acid (TBA) and total volatile base nitrogen (TVB-N)) and microbial parameters (total viable count (TVC) and psychrotrophic count (PTC)) were measured on days 0, 3, 6, 9, 12 and 15. A significant difference (P <0.05) was observed between the pH of the treatments containing the essential oil and the control in the last days of storage. The results showed that the PV, TBA and TVB-N values of treatments increased during storage. So that the least increase was observed in the fillet containing essential oil, pad containing essential oil and control respectively. The TVC and PTC count of treatments significantly increased during storage (P <0.05). But this increase was less in the fillets containing essential oil than the other treatments. According to the results of this study, it can be concluded that the absorbent pad containing Zataria multiflora leaf essential oil cause the quality preservation and shelflife increase of Hypophthalmichthys molitrix fillet during refrigerated storage.

The stability of disinfectants in water is one of the desirable features of these compounds. The physicochemical conditions of water, such as hardness, pH, salinity, and etc., can affect the performance of disinfectants. The present study was designed to evaluate the effect of different water salinities on the antimicrobial properties of commercial REMOVE disinfectant (combination of benzalkenium chloride and glutaraldehyde) against some true and opportunistic pathogenic microorganisms of fish. First, four bacterial strains including Streptococcus iniae, Aeromonas Salmonisida, Vibrio Harveyi, and Streptococcus agalactiae, and three fungi including Aspergillus niger, Fusarium oxysporum, and Saprolgenia spp. were selected and cultured on appropriate condition. Then, 1-3Í106 dilutions of each microorganism were prepared and REMOVE activity was evaluated (in two concentrations of 20 ppm and 10 ppm) in different salinity concentrations (0, 20, 40 ppt) in two time periods of 20 and 40 min. The viability of the studied microorganisms was assessed by disc diffusion and in a liquid medium under laboratory conditions. There was no significant differences in viability of studied microorganisms between the two concentrations of 10 and 20 ppm in different salinities (p>0.05). However, increasing the salinity to 20 and 40 ppt had a significant effect on the viability of the microorganisms in comparison with 0 ppt salinity (p<0.05). At 40 ppt concentrations, the highest amount of CFU/ml was observed in V. harveyi. Although disinfectant is able to reduce the population of microorganisms in different salinities, however this reduction is not very effective compared to 0 ppt concentration. Therefore, based on the results of the present study, it is possible that this disinfectant can be used to reduce the population of microbes in salty waters, but this reduction in practice alone will not be effective enough and requires the use of other controlling programs besides.

Every year the trend of catches and the maximum harvestable water from the water resources are studied and studied. Extensive studies of catch data have been conducted to estimate reserves. The main objective of this study was to predict Caspian mullet catch by decision tree algorithm (C&R tree) presented using Clementine 18 data mining software. Decision tree structure in machine learning is a predictive model that contributes to the observed facts about a phenomenon with inferences about the objective value of that phenomenon. For this purpose, 10-year catch data as a dependent variable (year of catch, month of catch, latitude and longitude of catch point, depth of catch, rate of catch) derived from bony fish stock assessment projects and environmental information (temperature, chlorophyll-a) From the NASA site and the factors of pH, transparency, salinity, oxygen, benthic organisms from northern seas hydrology projects) were considered as independent variables that besides specifying the effective factor on fishing, prediction of fish mullet in water The Caspian Sea also occurs. Among the investigated factors, water surface temperature and salinity were identified as the two main factors affecting fish mullet catchment and the prediction value for 1400, 862/484 tons of mullet with an accuracy of 98/42%.