Iranian Journal of Fisheries Sciences
Volume:19 Issue: 6, Nov 2020

The Iran Water Resources Management Company constructs many dams to control surface water that provide a new potential for aquaculture activities. Trophic status index and natural potential for fish production were investigated in nine small dam reservoirs from northwest of Iran. Prediction of fish productivity was calculated based on phytoplankton biomass (using chlorophyll a concentration in water; PChl-a) and benthic macro invertebrate biomass (PBMI). Average PChl-a and PBMI of reservoirs were estimated as 233.9±479.4 kg ha-1yr-1 and 14.76±19.18 kg ha-1yr-1 respectively. Concentrations of total phosphorus and total nitrogen varied between 0.023-0.345 and 0.42-3.58 mgl-1, respectively. According to Carlsonchr('39')s transformed model (TSIPN) the mesotrophic status was dominant in reservoirs in which TSIPN varied between 38.7 and 51.2. The eutrophication trend seems to be very fast in these reservoirs because of high nutrient input by aquacultures activities. The usage of fertilizers and amounts of food for aquaculture proposes and expansions of exotic species decline the natural fisheries potential of these reservoirs. Maintenance of water quality and investigation of native species should be planned to preserve sustainable fisheries activities in these reservoirs.

Effects of different dietary supplements of plant carotenoid sources on growth, coloration and behavioural activities of Trichogaster fasciata were carried out. Three groups of fish were fed with petal powder of rose (Rosa chinensis), China rose (Hibiscus rosasinensis) and marigold (Tagetes erecta) separately as carotenoid source along with the same basic ingredients for 90 days. The mean final weight of marigold petal powder fed group was significantly different (p<0.05) from other groups after 90 days of the experiment. The absolute growth rate, relative growth rate, weight gain percent and specific growth rate were highest in the group of fish fed with marigold petal powder while feed conversion ratio was lowest in this group. Carotenoid content in the tissue of different groups of the fish was found to be significantly different (p<0.0001). Marigold petal powder was most effective to enhance the pigmentation and coloration in the different color zones (color of eye and opercular ocellus, jugular darkening, anal, ventral and dorsal fin color etc.) of the skin of T. fasciata. Pigmentation affected the behavioural activities of the fish where male aggression and selection of males by females was high in the group fed with marigold petal powder. No significant difference was observed in the social interactions and habitat preference.

In the present study, population characteristics of Thunnus albacares were evaluated by sampling at five fish landing sites in the northern Oman Sea including Beris, Ramin, Pozm, Konarak and Jask from March 2017 to March 2018. The biometric analysis was performed on more than twenty-six thousand fish. Population dynamic parameters were calculated including infinite length (L∞=171 cm), growth coefficient (K=0.54 (yr-1)), growth performance index (Фchr('39')=4.19), natural mortality (M= 0.71(yr-1)), fishing mortality (F=1.57 (yr-1)), total mortality (Z=2.28±0.19 (yr-1)), exploitation coefficient (E=0.68 (yr-1)) and initial condition parameter (-0.18 yr-1). Relative production per recruitment, relative biomass per recruitment and exploitation rate of this species were Ychr('39')/ Rp = 0.04, Bchr('39')/ Rp=0.23(yr-1) and U=0.62 (yr-1), respectively. The Pobj value is <1, Popt and Pmega>0, and F/Fmsy>1. The results indicated that regarding length frequencies of this species in the northern part of the Oman Sea, yellowfin tuna stock has good conditions, but overfishing of this species is happening, now. Therefore, specific measures should be taken to reduce catch and fishing effort.

In the present study, a trophic structure model for some fish species of the northern Oman Sea is developed through using mass balance modeling software, Ecopath with Ecosim (EwE). In this model, we simulated 16 functional groups spread across an area of 3998.20 km2 from 2017 to 2018. Mean trophic level in the area of the present study was 3.49. Values calculated for system omnivory and connectance indices were 0.42 and 0.44, respectively. However, the values of ecotrophic efficiency in the model were high (>0.5) for most consumers of high trophic levels except for sharks and rays because of their high fishing mortality. Accordingly, mixed trophic impact showed that phytoplankton and detritus positively impacted almost all ecological groups. Also bentho-pelagics, the medium demersals, benthos, and crustaceans had a very negative impact on themselves due to cannibalism. Furthermore, the highest realized trophic level was 4.34 for sharks. The maximum omnivory index is calculated as 0.99 for medium demersals for feeding on a wide variety of preys. Also, the average catch per net primary production, i.e., the gross efficiency of the system was around 0.000198 (lower than the global average) indicating that the fishery is harvesting fishes high in the food chain. The primary production/respiration (PP/R) ratio is found to be 3.57 and the values of ascendancy (45.40%) and overhead (54.60%) showed stability of the ecosystem. Thus northern Oman Sea can be classified as an immature ecosystem (in the developmental stage), although it has some kind of system maturity. Accordingly, the food web of northern Oman Sea is consisted mostly of detritivorous, planktivorous, and carnivorous fish species. Besides, Ecopath with Ecosim (EwE) software can be an excellent option to examine interactions among ecological groups, and the impact of fishing in northern Oman Sea which is unquestionably helpful to develop concrete management strategies. The proper ecosystem-based fisheries management practice can improve the efficiency of this overexploited ecosystem.

Our study was focused on characterization of dominant Bacillus bacteria isolated from the digestive tract of Oncorhynchus mykiss. After 8 weeks, the fish fed with probiotic-free diet were dissected under strictly controlled conditions. Fish intestines were eviscerated and its content diluted to 10−4 using Ringer solution. Two isolated bacteria were Gram-positive, catalase-positive, and oxidase-negative, based on the biochemical tests. A mixed of the two strains was the most efficient isolates determined in O. mykiss. Molecular characterization using PCR-Ribotyping was carried out using sequencing the 16S rRNA gene of both strains, which isolated two bacteria, Bacillus subtilis Ahari.H1 and B. licheniformis Ahari. H2. The isolated bacteria could tolerate 0.3% bile salt and non-hemolytic in nature. They also showed resistance to pH at 2.5 and 4 for acid test and 2.3 and 7 for gastric juice, pepsin and trypsin. It is concluded that the efficiency of the isolated probiotics can be candidates as probiotic in fish culture. It was unveiled that these strains can successfully diminish Aeromonas hydrophila pathogenicity in rainbow trout.

Grass carp reovirus (GCRV), with high genetic diversity, seriously affects grass carp farming. Meanwhile, interferon regulatory factor 3 (IRF3) and non-specific cytotoxic cell receptor protein-1 (NCCRP-1) play crucial roles in immunity system of fish. In this paper, we took IRF3 and NCCRP-1 as molecular markers in order to explore the differences in immune responses of grass carp infected with different GCRV strains, which is helpful in better understanding of the GCRV pathogenesity. Accordingly, we analyzed the expression differences of IRF3 and NCCRP-1 in grass carp after challenges with GCRV GD108 (genotype III) and GCRV 096 (genotype I) by qRT-PCR. We found IRF3 and NCCRP-1 was up-regulated in all tested tissues after challenges of GCRV GD108 and GCRV 096. However, the expression levels of IRF3 and NCCRP-1 depended on the GCRV strain, and the up-regulation changes were qualitatively similar but quantitatively different after challenges of GCRV GD108 and GCRV 096, that is, NCCRP-1 was up-regulated more, earlier, and more broadly than IRF3 after GCRV challenge. Besides, the NCCRP-1 was more rapidly up-regulated to a greater extent after challenges with GCRV 096 than GCRV GD108. In order to clarify whether the antiviral immune response and development of grass carp hemorrhage in grass carp differed depending on GCRV genotypes needs more investigation. Moreover, we speculated that the GCRV-induced signaling pathways in grass carp were enriched with measles- and influenza A-induced signaling pathways, and found 13 types of new genes in the GCRV-induced signaling pathway.

Alkaline pH is one of the most important problems of our aquatic habitat. We used Stigonematalean native cyanobacterium Fischerella sp. FS 18 as our model strain, andstudied it under different alkaline pHs (7, 9 and rarely 11) under two different – short and long- time treatments (24 and 96 hours after inoculation). Spectroscopic results showed that both alkalinity and time affected growth rate, phycobilisome and chlorophyll production. Response surface plot analysis of distribution showed that the pH borders between 8.5 to  9 would be critical at 24 hours after inoculation reaching to the highest rates of phycobilisomes. Spectrofluorimetric analysis showed that the highest photosystem I/ photosystem II may be seen at 24 hours at pH9. Photosynthesis- Irradiance curves showed that the highest rate of maximum photosynthesis belonged to pH9 in the short time treatment (24 hours). Increasing the time (96 hours) decreased the maximum amount of oxygen liberation significantly. Moving from the optimum conditions (even slightly) caused a sharp decline in the amount of alpha. The slope of decline was steep until near neutral and longtime condition.  Decreasing the time, and at the same time increasing alkalinity (alkaline pH) caused higher activity of photosystems especially photosystem I which lead to higher reductant production and cyclic electron flow operation. Distinct borders of pH (8.5-9) at 24 hours caused considerably high growth and matter production. This was naturally true for phycocyanin, phycoerythrin and the other economically important matters.

Bisphenol A (BPA) is a synthetic compound widely used in types of consumer goods and medical tools. It has been shown that BPA acts as an endocrine disruptor chemical casuing negative impact on reproductive functions. The present study used an in vitro approach to assess estrogenic transcriptional activity of BPA as a rapid and sensitive method. The cultured pieces of hepatic tissue of goldfish (Carassius auratus) were exposed to 1, 5, 25 μg L-1 BPA and 1 μg L-1 E2 for comparison over 24 h. Compared to control, the mRNA transcript of erβ-I showed a significant increase in the hepatic tissues exposed to all doses of BPA and E2. The mRNA transcript of erβ-II was signifincantly increased in hepatic tissues exposed to 1 and 5 μg L-1 BPA and E2. The mRNA transcripts of vtg in the hepatic tissues treated with 5 μg L-1 BPA and E2 were also increased, significantly. Finally, cyp1a mRNA transcript showed a significant increase in the hepatic tissues exposed to 5 and 25 μg L-1 BPA and E2. These results show an estrogenic activity of BPA similar to E2, and suggest that in vitro approach can be used as an alternative to in vivo test to detect estrogenic effects of BPA.

Anesthetic agents are used in fish to decrease stress and mortality during sorting, surgery, diagnosis and artificial fertilization procedure. This study was done to evaluate and compare the efficacy of propofol and clove oil for anesthetizing Capoeta damascina. For this purpose, 40 fish were caught from Arvand River and divided into two groups. After a pilot study, propofol and clove oil were examined in 12.5 mg L-1 and 125 mg L-1 concentrations, respectively. The onset of anesthesia, duration period of anesthesia and recovery time were recorded separately for each group and compared. Results showed that the anesthesia onset of specimens in propofol treatment, was significantly shorter than that of clove oil treatment (p<0.05). Also, recovery time in propofol treatment was longer (p<0.05) than that of clove oil. Based on the results, it was recommended to use propofol instead of clove oil in performing anesthesia for this species due to rapid induction, longer duration and more prolonged effect in immersion method.

This study compared the biomass production, fucoxanthin production and antioxidant capacity of the fucoxanthin from the marine haptophyte algae, Isochrysis galbana under different nitrogen concentrations. At first step in the salinity test, I. galbana could grow in 20‰ and 35‰ but the 35‰ salinity was optimal. At second step, five different nitrogen concentrations (N-NO3) of 2, 4, 8, 12 12 mM, at the salinity of 35‰, were investigated. Algal cell density increased as nitrogen concentrations increased, but a low growth rate occurred in the culture with the highest nitrogen concentration (12 mM). The maximum cell density of 72×  and the maximum amount of fucoxanthin (18.1 mg g-1) was obtained in I. galbana cultured in media containing four mM nitrogen (N-NO3). The purified fucoxanthin exhibited strong antioxidant properties, with the effective concentration for 50% scavenging (EC50) of 1, 1-dihpenyl-2-picrylhydrazyl (DPPH) radical, being 0.2 mg/ml. This study suggests that the production and fucoxanthin concentration of I. galbana can be improved using nitrogen-replete culture in 35‰ salinity. Also under this condition this microalgaecan be a commercial source of fucoxanthin for human health and nutrition.

In the present study, the weaknesses, strengths, opportunities and threats of fishmeal industry have been examined using the SWOT analysis. After interviewing a number of experts and searching through different resources, the questionnaire was designed. A total of 42 people and experts involved in this industry in the present study. 14 strengths identified, such as several years of working experience, 27 weaknesses for example shortage of raw materials, 14 opportunities, namely the increase in fishmeal demand due to the growth in aquaculture and 19 threats including the increase in foreign currency fluctuation were considered in IFE and EFE. The most important strategies are conservative and defensive, approach utilizing modern technology and interacting with the global market, using the environment friendly technologies, more interaction with the government through :union:s in order to gain credit facilities, helping to decrease cost price of industry accessory, regular support for Iranian products, helping the production of the necessary technology inside the country, examining the possibility of providing more raw materials inside the country and using new reserves, will assist the supervisors of this industry in designing and writing a strategic plan to develop the fishmeal industry.

Caspian brown trout, Salmo caspius, were subject to five temperatures (5°C, 8°C, 20°C, 25°C, and 28°C) for two durations 12 and 24 hours. The fish were maintained for 48 hours at a water temperature of 9-10°C to acclimatize. The water temperature was changed gradually at a rate of 2°C per hour to the respective temperatures. Exposure to temperatures of 25 and 28°C resulted in loss of all fish. Red blood cell, hemoglobin concentration, and hematocrit were decreased at 5°C compared to control (8°C) and 20°C in duration of 12h. Temperature tension did not affect the mean cell volume and mean cell hemoglobin value during the 12 and 24h duration (p>0.05). Neutrophils percentage was  significantly higher at 5°C and 20°C, but the most percentage of lymphocytes was noted in the control group. Cortisol, glucose, and lactate values elevated in both periods when water temperature decreased to 5°C compare to the control and 20°C groups (p<0.05). The levels of albumin and total protein in the duration of 12h at 20°C were significantly higher than control and 5°C, but this trend was not seen in the exposure of 24h (p<0.05). The lysozyme activity and immunoglobin M were affected by varying temperatures (p<0.05), and highest levels were observed in control groups.  Most histopathological changes in gill, such as epithelial hypertrophy, curling of lamella, and necrosis of the epithelial cell were observed at 20°C; whereas these were less affected at 5°C and 8°C.  Lowest hemorrhages in the spleen and lowest size of sinusoids were observed in 8°C and 5°C treatments respectively. Overall, temperature variation had a superior impact on gills than spleen. Taken together, the results of the present study showed that sudden variation beyond the optimum temperature leads to physiological and pathological changes.

The present study investigated the effects of Cd, Cu and Zn on the sperm motility of Caspiomyzon wagneri. The sperm of the specimens were exposed to 0.01, 0.1, 1, 10, 100 and 1000 mg L-1 of the heavy metals, and the duration of sperm motility and percentage of motile sperms were measured using a compound microscope and digital camera. Based on the results, sperm motility parameters decreased with increasing the concentrations of heavy metals. A concentration of 1000 mg L-1 of heavy metals stopped completely the motile sperms. The present study indicated that heavy metals have detrimental effects on sperm motility and possibly decrease the fertilization and hatching rates of C. wagneri in the spawning ground, and thus a serious threat to the survival of this rare and native species.

The aim of the study was to access the influence of nigiri sushi meal ingredients ratio on its weight, nutritional profile, physic-chemical characteristics (crude protein, lipid content, ash content, salt content, phosphorus content and thiobarbituric acid assay) and to estimate the usage of citrate synthase activity as freshness index of seafood used for sushi preparation. Nutrition composition of nigiri sushi is highly influence by rice/seafood ratio. Inclusion of processed seafood in sushi can influence significantly weight and consequently nutritional profile of nigiri sushi meal as well. Shrimp cooking resulted in 16.45±3.29% weight loss in whole non-deveined shrimp and 13.03±3.40% in non-deveined shrimp tail. Nigiri sushi meal prepared with salmon and tuna fish can be recognized as good sources of seafood. Nigiri sushi meal can be considered as a low-calorie meal (nigiri salmon: 716.13±24.18 kJ/100g; nigiri tuna: 638.12±10.64 kJ/100g; nigiri shrimp: 672.06 ± 8.72 kJ/100g) but on the contrary it cannot be considered as low salt content meal (nigiri salmon: 0.97±0.04%; nigiri tuna: 0.89±0.10%; nigiri shrimp: 1.06±0.13%). Citrate synthase activity (CSA) increases after each freezing/thawing cycle and at the end (4th cycle) were 5.29±0.67 μmol/mL/min and 6.67±0.63 μmol/mL/min in tuna and salmon samples, respectively. CSA can be recognized as reliable enzymatic kit indicator for fish freshness determination in nigiri sushi meal.

Low fertilization rate and hatchability of cultured Dabry’s sturgeon, Acipenser dabryanus, are bottlenecks to the fish species protection, while adequate nutrients in body of subadult fish are crucial to successful reproduction. The present study was conducted to preliminarily understand the nutritional status of male and female subadults by characterizing the proximate composition, fatty acid and amino acid profiles in muscle, liver and gonad of farmed Dabry’s sturgeon with gonads at stage II through chemical analysis, gas chromatograph and high pressure liquid chromatography. The results showed that lipid content (47.24%) in gonad of females was significantly higher than those in liver (29.26%) and muscle (7.72%), while lipid content (39.43%) in liver of males was significantly higher than those in gonad (18.40%) and muscle (6.68%) (p<0.05). The protein content (5.81%) in gonad of females was significantly lower than those in liver (10.77%) and muscle (22.82), while protein contents in gonad (9.23%) and liver (8.72%) of males were significantly lower than that in muscle (20.83%) (p<0.05). The contents of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in gonad and muscle were the most abundant n-3 polyunsaturated fatty acids (n-3 PUFAs). The content of arachidonic acid (ARA, 0.65%) in gonad of females was significantly higher (0.33%) than that in gonad of males (p<0.05). The results suggest that lipid and highly unsaturated fatty acids, such as ARA, EPA and DHA are accumulated in the gonads at stage II, which may play pivotal roles in gonad development.

The present study examinesthe fisheries governance status of small-scale capture fisheries in the northern Persian Gulf. Qeshm Island, which is selected as case study, plays a prominent role in fisheries in the Persian Gulf and territorial waters of the country. The research methodology included in-depth and semi-structured interviews with heads of fisheries cooperatives and fishers to deepen our understanding of the cultural and technical characteristics of local fisheries communities. Subsequently, data was drawn from 322 questionnaires, using a random sampling technique. The analyses indicate that fisheries co-management is at an interstitial situation, while the fishers are willing to cooperate with the government. A finding is also showed that literacy has a significant effect on fishers’ willingness to cooperate with government. There was also a considerable conflict of interest among the fisheries communities in the study area, which makes the implementation of rules difficult. Small-scale fishing communities are generally in a hard-pressed situation, which affects how fishers operate. Our study aims to contribute to improving the governance and governability of small-scale capture fisheries in the region.

Amino acid profiles, functionality, and antioxidative potential of orangefin ponyfish (Photopectoralis bindus) protein hydrolysates, using 1% Alcalase, with diverse hydrolysis times (1, 2, 3 and 4 h), were evaluated. The samples solubility in the pH range of 3-9, emulsifying and foaming properties at various protein contents (2.5, 5 and 10 mg/mL), as well as the scavenging of DPPH, ABTS free radicals and reducing power (at concentrations of 1-5 mg/mL), were studied. The amino acid profile of orangefin ponyfish was used to estimate nutritional value. A high amount of essential amino acids (35%) involved in protein hydrolysates and Glx, Asx, and Gly were the dominant amino acids. Solubility was above 90% in the pH range 3-9 and increased at all hydrolysis times by changing the pH from acidic to alkaline (p˂0.05). The emulsifying activity (EAI) and stability (ESI) indices were reduced with increasing hydrolysis; at 2.5 mg protein/mL, 1h hydrolysates displayed the highest EAI (87 ± 2 m2/g) and ESI (22 ± 0.4 min), when considered with those possessing higher hydrolysis time. On the other hand, the foam expansion and stability increased with increasing hydrolysate content. Antioxidant activity of hydrolyzed protein increased with increased hydrolysis (up to 3 mg/mL), especially DPPH and ABTS. However, the highest DPPH and ABTS scavenging activity of FPH was about 73% and 93% at 5 mg/mL hydrolysate concentration and hydrolysis time 4 h, respectively.

Because of the importance of rotifers as an adequate live food in larviculture, this study was conducted to evaluate probiotic potency of four microorganisms, Candida parapsilosis, Pseudoalteromonas flavipulchra, Lactobacillus sakei and Bacillus natto on suppression of Vibrio species and increasing population growth, enzymes activity and nutrients retention in the rotifer, Brachionus plicatilis. Four experimental and a control treatment, each with four replicates, with the concentration of 108 CFU/mL-1 for each strain were applied. The results demonstrated that L. sakei and B. natto successfully suppressed Vibrio in experimental treatments and increased population growth and nutrients retention. The longevity of B. natto was recorded as the best in long-term inoculation than other treatments and the control in a way that after 8 days of rotifers starvation, the count of B. natto increased. The findings showed that the two bacteria, B. natto and L. sakei, appear to be a promising probiotic for rotifers in suppressing Vibrio and also in increasing population growth, nutrients retention, enzymes activity and long-term inoculation in rotifers.

Asteroidae, or starfish, is one of the classes of phylum Echinodermata that its phylogenetic relationships have not been studied in the Persian Gulf so far. In this research, the morphological identification, molecular analysis and phylogeny of 40 asteroid samples were studied from the northern islands of the Persian Gulf. For this purpose, starfish samples were identified using morphological characteristics. The molecular identification was performed based on two fragments of mitochondrial cytochrome oxidase subunit I (COI) and mt 16S rRNA. The phylogenetic relationships of asteroids were analyzed using maximum likelihood, maximum parsimony and Bayesian methods.  Eleven species of starfishes belonging to 6 genera as well as 5 families have been identified including Luidia hardwicki, Astropecten hemprichi, Astropecten indicus, Astropecten polyacanthus phragmorus, Astropecten polyacanthus polyacanthus, of Culcita novaeguineae, Pentaceraster mammillatus, Linckia laevigata, Linckia multifora, Aquilonastra iranica and Aquilonastra watersi. Since the species of Linckia laevigata (orange-green morph) and a specimen of Astropecten polyacanthus polyacanthus have been identified based on molecular analysis, this technique can be a useful tool in asteroids along with morphological studies. The obtained interspecies distances in genera Luidia and Astropecten suggest cryptic speciation might have occurred in these genera. The results of Asteroidae classifications at the genus and family levels indicated phylogenetic tree of mt 16S rRNA gene based on Bayesian method is consistent with previous morphological taxonomic and phylogenetic analyses.

In this study the distribution and accumulation of diazinon, malathion and azinfos methyl in mullet fish Liza aurata, caspian white fish Rutilus frissi kutum and common carp fish Cyprinus carpio from five estuaries along the Caspian Sea was investigated. Also, the effect of pesticides concentration on the acetylcholinesterase enzyme (AChE) in fish species was studies. Pesticides concentration varied with fish species, sampling station and toxin type. The results indicate that the pesticides concentration varied from 0.01 to 0.16 mg/kg for diazinon, 0.01 to 0.15 mg/kg for malathion and 0.05 to 0.36 mg/kg for azinfos methyl in three fish species. There was significant difference between different toxin concentrations in fish species, (P < 0.05), and the order of toxic concentrations was as follows: azinfos methyl > diazinon > malathion. There was significant difference in toxin concentrations between three fish species, and the highest toxins concentrations were absorbed in detritivores fish (L. aurata), followed by herbivorous fish (C. carpio) and carnivore fish (R. kutum). The results confirmed that toxins bioaccumulation in fish species is strongly controlled by habitat and feeding habits.

Sex steroids (testosterone, progesterone and 17β-estradiol) play important roles in controlling reproduction and sexual maturity in teleosts. The aim of the present study was to evaluate the seasonal changes of these steroids in Rohu Labeo rohita. Forty gravid females and males L. rohita reared in different seasons (spring, summer, autumn, winter) were caught by a net with 1 cm mesh from earthen ponds of Aquaculture Research Institute, in south of Iran. The highest levels of 17β-estradiol (122.8±17.73 ng mL-1), testosterone (0.11±0.003 ng mL-1) and progesterone (0.86±0.01 ng mL-1) in female fish were recorded in autumn. In addition, the highest concentration of testosterone in male was determined as 0.84±0.003 ng mL-1 in autumn. The mean value of dissolved oxygen in four seasons (spring, summer, autumn, and winter) were 9.21±0.77, 8.36±0.51, 10.41±0.9 and 13.14±0.72 mg L-1, with temperature 25.47±1.07, 29.88±1.42, 20.23±0.69 and 14.63±0.47 ◦C, respectively. Therefore, it can be inferred that progesterone was considered as the critical index for seasonal breeding selection. There was an appropriate condition in the mid winter for broodstock selection and breeding of fish with hormones manipulation.

Food safety standards are one of the major non-tariff barriers of global trade. We investigate their effects on fish international trade patterns, especially for the developing countries. The main objective of this study is to investigate the role of mercury standards on Iran’s fish exports. We utilize the gravity model  analysis based on balanced panel data model, covering eight importing countries over the 2006-2015 period. The estimated coefficient of mercury standard supports the hypothesis that fish safety standards are one of the important factors affecting fish exports. Moreover, regulation similarity between countries could increase fish trade. Other explanatory variables of geographical distance between countries, trade agreement between countries and real exchange rates also have a significant effect on fishery product exports. The results indicate that Iran’s fish exports are negatively correlated with mercury standards of importers. As a result, adapting fisheries product standards and producing with the methods to deal with mercury standard imposed by importing countries is crucial for increasing Iran’s fish exports.

Lactic acid bacteria are the most common bacteria which have been introduced as probiotic. This study aimed to investigate the impacts of isolated lactic acid bacteria from the Rutilus kutum gut   on Escherichia coli and Pseudomonas aeruginosa. Lactic acid bacteria were isolated from the intestine of 100 fish which are randomly collected from the Caspian Sea and their primary probiotic properties were evaluated based on resistance to acid, bile salts and antibiotics. The inhibitory effect of the bacteria was evaluated on Escherichia coli and Pseudomonas aeruginosa, using the agar disk diffusion method. The specific band was triggered using PCR primers for 16S rRNA gene and validated via sequencing and comparing its sequence with those of gene bank databases. In this case, Lactobacillus acidophilus (54.79%), Lactobacillus plantarum (24.65%), and Lactobacillus brevis (20.54%) were detected. The isolated bacteria were resistant to vancomycin. The most inhibitory effect belonged to Lactobacillus acidophilus sp. on E. coli and P. aeruginosa; with the inhibition zone of 12 and 14 mm, respectively. Lactobacillus plantarum had moderate inhibitory effect on P. aeruginosa while Lactobacillus brevis had neither effect on E. coli nor P. aeruginosa.

Gonads of sea urchin attract consumers due to its high nutritional value than any other seafood delicacies. Aquaculturists are also very keen on developing larval culture methods for large-scale cultivation. The present investigation systematically examined the larval rearing, development, survival and growth rate of Salmacis bicolor fed with various microalgal diets under laboratory condition. Fertilization rate was estimated as 95%. The blastula and gastrula stages attained at 8.25 h and 23.10 h post-fertilization. The 4 - armed pluteus larvae were formed with two well - developed post-oral arms at 44.20 h following post-fertilization. The 8 - armed pluteus attained at 9 days post fertilization. The competent larva with complete rudiment growth was developed on 25th days post - fertilization. Monodiet algal feed - Chaetoceros calcitrans and Dunaliella salina resulted medium (50.6 ± 2.7%) and low survival rate (36.8 ± 1.7%) of S. bicolor larvae. However, combination algal feed – Isochrysis galbana and Chaetoceros calcitrans has promoted high survival rate (68.3 ± 2.5%) which was significantly different between the mono and combination diet. From the observations of the study, combination diet could be adopted as an effective feed measure to promote the production of nutritionally valuable roes of S. bicolor.

Trustocytrides have received a great deal of attention in recent years for producing a significant amount of omega-3 fatty acids. However, their commercial and sustainable production from microalgae sources faces technical and economic limitations. In this study, the effect of temperature and different carbon and nitrogen sources in YEP calture on the growth and fatty acids profile in a newly isolated strain of Aurantiochytrium sp. SHY has been conducted. Glucose produced more biomass, but galactose was more suitable for lipid formation. Galactose promoted the highest production of fatty acids (36.4%), but the ratio of docosahexaenoic acid to fatty acids was 19.05% which was less than glycerol. With an increased glucose concentration, EPA is considerably higher and DHA is only slightly increased. This is the first study that has been carried out on this new isolate wherein a mixed carbon source was used in the culture media and the results showed the microorganism’s preferences for carbohydrate consumption is in the following pattern: glucose > galactose > fructose> sucrose. The meat extract was the most suitable nitrogen source for biomass development (7 g L-1), but the maximum DHA to fatty acids ratio (25%) was achieved when the microorganism consumed monosodium glutamate as a nitrogen source. The strain produced more biomass at 25°C, and lowering the temperature achieved a higher DHA formation. The results of this study show that if this strain is going to introduce as a good potential candidate for food industries and aquaculture, it needs more study in bioreactor that’s going on.

The present study considers community variability and structure at taxa-groups of macro-fauna. Sampling was carried out in three seasons at three zones in intertidal rocky shores of Bushehr, Persian Gulf. In this study, 1936 individuals belonging to 66 species were collected. These are classified into 12 groups. The mollusks were abundant in all three sites in winter and also low zone in all seasons. In contrast, Portunid crabs and Polychaets were the lowest abundant groups. All zones in three stations were occupied by mollusks and were dominated by Planaxis sulcatus and hence the community is named "P. sulcatus ". Due to habitat diversity, the most abundant decapod groups were xanthoid and porcelanid crabs.

Mass mortality of Catfish Netuma thalassina during the peak summer in Kuwait Bay prompted the study of mercury concentrations using direct mercury analyzer (DMA-80) during the ‘fish kill’ otherwise, found below the detectable limits. The mean mercury (Hg) concentrations in seawater, sediment and body parts of N. thalassina (0.27 ng L-1, 0.35 ng g-1, 0.23 ng g-1) was high during ‘fish kill’ on 29th April, 2017 when compared aftermath the ‘fish kill’ (0.20 ng L-1, 0.29 ng g-1 and 0.15 ng g-1) respectively. Hg concentrations in the collected samples were observed in the sequence of Site-II>Site-I>Site-III. Fish stress was validated by hepatosomatic index (HSI). During ‘fish kill’ a decrease in liver weight due to liver shrinkage against their body weight was observed in contrast aftermath the ‘fish kill’. Mass mortality of N. thalassina was also suspected because of underwater explosion-a plan that is adopted when complex construction activities were made across the Kuwait Bay sites. Since, fish with swim bladder is susceptible to explosion, environmental variations and hazardous effluents, such factors are validated, and futuristic research delved in this line.

A total of 150 carp fish were collected from Grdarasha Farm (8 kilometers from Erbil-Iraq) and examined for the presence of pathogenic Aeromonas hydrophila on their skin ulcers, this bacterium secretes a toxin protein called aerolysin which is a virulence factor and has a role in diarrhoeal diseases, deep wound infections and hemorrhagic septicemia. The present study aimed to determine the presence of A. hydrophila in common carp (Cyprinus carpio). For this purpose samples were collected from fish ulcer by swap and incubated at 37°C in blood agar to determine the shape and morphology of colonies, and then the colonies were examined by gram stain test for microscopic examination, finally molecular diagnosis was conducted for aerolysin gene with primer design and PCR. According to the diagnosis methods results were different; PCR diagnosis confirmed that only 68 skin lesions were caused by A. hydrophila, no visceral lesion was caused by A. hydrophila and this bacterium hardly ever seen in the skin surrounding mouth as only 2 lesions surrounding mouth had A. hydrophila in PCR diagnosis.

The application and development of nanotechnology is increasingly expanded in many areas. However, considering this expansion, several concerns regarding their potential toxicity in marine biology have been addressed. Indeed, the overuse of these materials can adversely influence marine ecosystems and living organisms. Herein, the potential impact of copper-based nanoparticles on the expression level of three genes, i.e. prophenoloxidase, serine protein and glutathione peroxidase genes functioning in shrimp immune response, were assessed. For this end, the shrimps were exposed to three semi-acute toxicity treatments, including 0.25, 0.5 and 1 mg/L of CuNPs. The qRT-PCR results indicated negative effect of supplied nanoparticle on the expression level of these genes. Additionally, histopathological alterations in the hepatopancreas and lymphoid organs were observed in the shrimps after exposure in different concentrations of CuNPs. Overall, we showed that toxic concentration of CuNPs can damage shrimp immune system as well as some internal organs. These results open up novel insights into innate immunity of shrimps subjected to copper-based nanoparticles.

Farming of the pacific  white leg shrimp (Penaeus vannamei), consists the greatest percent of aquaculture production of crustaceans all over the world. Vibriosis caused by Vibrio species such as Vibrio alginolyticus, is a serious limiting agent for aquaculture. Phage therapy is an eco-friendly alternative to antibiotics as a prophylactic measure for the growth of pathogenic bacteria. The aim of this study was isolation and characterization of Vibriophages present in Litopenaeus vannamei breeding and culture facilities and estuarine resources in south west of Iran, Choebdeh shrimp farming site of Abadan city, Khuzestan Province, based on morphological structure, biological conditions and their potential applications in lysis of Vibrio bacteria. The bacterial and phage samples were analyzed using different physicochemical parameters, 16S rRNA gene sequencing and TEM. The results showed the V. alginolyticus isolates and identified the Podoviridae family of phages. These bacterial isolates were resistant to ampicillin and penicillin. The efficacy of the Podoviridae phage against V. alginolyticus bacterium indicated that this phage has a short period of 30 minutes latent phase, possessed a desirable stability and growth in keeping for 1 hour at 30-55oC, the salinity of 0.5-10  and pH of 5-8. Based on evaluation of phage therapy, mean absorbance values (OD600), in control and treatment groups, at 12 and 24 hours after phage inoculation, were significantly different (p<0.05). According to the results, phage therapy with single-phage suspensions did not prevent bacterial regrowth after treatment. However, delay in development of resistance is a desirable success.

The genetic variation and population structure of the Persian sturgeon, Acipenser persicus (Borodin, 1897) was investigated by means of polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) analysis of the nucleotide dehydrogenase subunit 5 (ND5) of mitochondrial DNA (mtDNA). We compared these data with our previous study based on mtDNA control region sequences. A total of 225 individuals were collected from 23 sample sites in the south and 4 locations in Turkmenistan, Azerbaijan, Russian Federation and Kazakhstan covering the three main geographic regions including south, middle and north part of the Caspian Sea. The PCR products were digested with 25 restriction enzymes and five enzymes revealed polymorphism patterns (Rsa І, Hinf І, HaeIII, Mbo І and Cfr13І). Thirty two composite haplotypes were revealed with the number of haplotypes in each population sample ranging from 6 to 13. Two regional (Sefidroud River and Russia) groups were clearly identified by cluster and molecular variance model (AMOVA) analyses. Each of these groups showed dominant haplotypes that were little in populations from the other geographic areas. The mean haplotype diversity (h) and nucleotide diversity (π) were 0.7610±0.046 and 0.008332±0.00421, respectively. Based on heterogeneity test and Monte-Carlo with 1000 replicates, significant differences were showed for haplotype frequencies of the Persian sturgeon populations (p<0.0001).  The obtained results and also FST based on kimura- 2 parameters method showed that haplotype distribution in different location were significant (p<0.0001). Results of this study determined independent populations of Persian sturgeon and will have noticeable implications for sturgeon conservation genetics in general.

In this study, Amirabad Special Economic was used as the study area, the distribution and tracing possible sources TPH, nickel, lead, vanadium, TP and TN were analysed in coastal sediments of 5 transects. According to our results the inner part of the 2 ports, are going to be slightly contaminated with TPH and heavy metals; meaning the contents of all the sites were lower than the background values. Based on physico-chemical parameters of water  and according to dbRDA, the separation of offshore and river area was observed. Based on TOM, TPH and sediment nutrients, PCoA separated river and Sadra port transects. Finally, it seems high inter-annual water MVDISP values, reflecting highly temporal dynamic condition, influence the transportation of sediments along a depth gradient proved by nMDS, and the consecutive resuspension of sediments to open water is strong enough to keep the contaminants from rising to very high levels.

This study aimed to identify the chemical composition of essential oil of some Iranian medicinal plants and their antifungal activity against Saprolegnia parasitica in comparison to formalin as positive control under in vitro conditions. The essential oils of Eryngium campestre, Pimpinella affinis, Mentha piperita, Achillea wilhelmsii and Cuminum cyminum were analyzed for their activity by disk diffusion, Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) methods. Also, the oil constituents of investigated plants were analyzed by gas chromatography/mass spectrometry (GC/MS). The major constituent of the surveyed essential oils was bornyl acetate (17.9%) in E. campestre, Pregeijene (27.3%) in P. affinis, menthol (48.5%) in M. piperita, 1,8-cineol (25.2%) in A. wilhelmsii, and α-Pinene (29.1%) in C. cyminum. The MIC values for the surveyed essential oil were was 0.5 µg ml-1 for C. cyminum followed by M piperita and E. campestre both having 1 µg ml-1, for P. affinis 2 µg ml-1 and was 4 µg/mL for A. wilhelmsii. The MFC for the mentioned essential oil were with 0.5 µg ml-1 again lowest for C. cyminum, followed by M. piperita and E. campestre with 2 µg ml-1, for P. affinis MFC was 4 µg ml-1 while it was with 8 µg ml-1 highest for essential oils from A. wilhelmsii. The results indicate that the essential oils of C. cyminun, E. campestre and M. piperita could be potential candidates for new plant based antifungal components in aquaculture against S. parasitica.

Changes in the peptide levels of sea bream (Sparus aurata) GnRH (sbGnRH) in the olfactory bulb, telencephalon including the preoptic area, hypothalamus, optic tectum-thalamus and pituitary during a reproductive cycle were investigated in addition to plasma levels of testosterone (T), 17β- estradiol (E2) and 17α, 20b-dihydroxy-4-pregnen-3-one (DHP) in wild female Asian sea bass Lates calcarifer in Nha Phu lagoon, Vietnam from March to September, 2010. Ovaries were classified into five stages: II Recovering spent (March -April), III Maturing (May-June), IV Mature (June), V Ripe and ovulating (July- August) and VI Spent (September). The gonadosomatic index increased significantly from the stage II (1.62%±0.12) to stage V (8.48%±0.23) and dropped thereafter in stage VI (2.05%±0.25). In the olfactory bulb and telencephalon, sbGnRH levels in stage IV and stage V were slightly higher than those in the other stages, but no significant differences in sbGnRH levels were found among the ovarian stages. In the hypothalamus and optic tectum-thalamus, although significant differences in sbGnRH level were not found among the ovarian stages, the highest level of sbGnRH was determined in stage III (594.13±152.12 pg tissue-1 and 501.37±124.35 pg tissue-1, respectively). In the pituitary, sbGnRH level in stage III (6927.03±218.92 pg tissue-1) was significantly higher than that in the other stages. In addition, plasma T, E2 and DHP levels increased significantly during ovarian maturation or ovulation with the highest level of T (2.91±0.31 ng ml-1) and E2 (4.98±1.43 ng ml-1) recorded in stage IV and DHP (389.6 ± 136.03 pg ml-1) in stage V. The results showed that sbGnRH in the anterior brain and pituitary is involved in initiation and ovarian maturation in wild Asian sea bass.

Lactoferrin (LF) has been used as an immunostimulant in different fish species and have effects on growth and immunological parameters. The aim of this study was to evaluate the effects of dietary LF on growth and feeding performance, body composition, digestive enzymes activity, hematological factors, humoral immune response and expression of immune-related and growth-related genes in sobaity juvenile (Sparidentex hasta). One hundred and thirty five fish with an initial average weight of 35.64±0.30 g were fed for a period of 8 weeks. Basal diet was supplemented with 0 (control), 400 and 800 mg kg-1 LF in a completely randomized design trial in triplicate groups. The results showed no significant differences in growth and feeding parameters and body composition between control and treatment groups (p>0.05). Moreover, no significant difference was observed in digestive enzymes activity, non-specific immune response, hematological parameters and immune-related gene expression (IL-1β) between control and the treatment groups (p>0.05). Nonetheless, growth-related gene expression (IGF-I) of treatments and control group significantly varied (p<0.05). These results suggested that dietary LF used in this study is not appropriate for supplementation in the diet of sobaity juvenile as it did not influence the growth performance, feed utilization, body composition and the physiological parameters in this fish. This study encourages further research on different aspects of LF in sobaity culture with a clear emphasis on optimizing dosage levels.

Plastics are the most important pollutants in oceans and seas and are regarded as serious threat to aquatic ecosystems. The effect of tide, wind and water depth on movement of plastic marine debris has been examined in north of Hormuz Strait in Hormozgan province coasts, Hormuz Island and east of Qeshm Island. Particle tracking is used by numerical modeling using MIKE software for time interval of January to March 2017. Field study and model output clarified that direction of the particle movement during a tidal period made an elliptical shape that the small diameter formed due to wind and the large diameter varied with tide motion. The highest movement of the particle was observed one hour after high water (low water) to one hour before low water (high water). Wind was the most effective parameter within one hour before and after low water (high water). At same the time interval, as the area deepened, more movement was observed. Tracking the samples showed that more than 60% reached Bandar Abbas coasts in less than 8 days after release. The other regions receiving the samples were coasts of Hormuz Island and East of Qeshm Island with estimates of 30% and 2%, respectively. The results can be used to forecast marine macro debris accumulation zones and time duration which assist the management system as a cleanup tool.

In this study, the occurrence of a parasitic helminth infecting a Turkish endemic fish, Manyas spirlin, Alburnoides manyasensis from the Nilüfer stream, Bursa, was studied from winter 2017 to autumn 2018. A total of 46 A. manyasensis were examined for the presence of the helminth. The helminth was identified as Paradiplozoon homoion (Monogenea: Diplozoidae) and occurred on the gills of host fish. A total of 115 specimens of P. homoion infected 32 of 46 fish examined, with prevalence and mean intensity of infection of 69.57% (41.67% in Summer to 90.00% in Winter) and 3.59 (1.00 in Summer to 6.22 in Winter) respectively. Additionally, prevalence and mean intensity of infection was calculated per seasons, host size and sex. The highest values for prevalence and intensity of infection were found in winter for P. homoion. To our knowledge, this is the first ichthyoparasitological study for A. manyasensis in Turkey. This is also the first record of P. homoion from this host fish and locality.

Diatoms have been recognized as source of important and applicable ingredients such as pigments and essential lipids. In this study, the effects of nitrogen and silicate changes accomplished by salt stress were investigated to analysis the chl a and chl c1+c2 contents, specific growth rate, total lipid percentage and fatty acid composition of Navicula sp. Samples were collected using by plankton net (30-micron pores) in spring 2019, from 6 stations in the Persian Gulf, Iran. In this study, samples were cultured under salt stress (control, 20ppt and 45ppt) and nutrients fluctuation (control: N: 0.5 mg, Si:0.3 mg, high nutrient culture: N:0.9 mg, Si:4.5 mg and without nutrient culture). There was a considerable decrease in dry weight and maximum growth rate under 45ppt salt treatment without silicate. The amount of chl a was not significantly changed under various treatments. The highest level of chl c1+c2 was related to 20ppt with nitrate (3.05 mg L-1 ) and the lowest value was 0.38 mg L -1 for 20ppt with silicate treatment. The highest level of total lipid content was obtained at 45ppt without silicate. Lipid composition analysis under 45ppt without silicate showed a significant increase (2.07 times compared to control) of palmitoleic acid (C16:1n-7) and trace amounts of polyunsaturated fatty acids were detected. Based on these results, it could be suggested that salt stress without silicate has an important effect to accumulate valuable lipids in Navicula sp. so that, they could be useful in medical and bioenergy applications.

Antibacterial activity of silver-impregnated vermiculite and silver removal capability of acid-treated vermiculite (Verm-A) were assessed through 4-stage water filtration systems. The antibacterial vermiculite was prepared through cation exchange process in silver nitrate solutions of 0, 500, 1000, and 2000 mgl-1 , named Verm-B0, Verm-B500, Verm-B1000, and Verm-B2000, respectively. The Verm-A was only treated with 1 M HCl to increase its negative zeta potential. Bacterium Aeromonas hydrophila was inoculated into the filtration systems and then total colony forming units in water samples was enumerated for 96 h. Flame atomic absorption spectrometer showed the maximum silver adsorption (49.17 mg/g) by Verm-B2000. Scanning electron microscopy micrographs illustrated silver with nano dimension crystallites with the average sizes of 274.808, 194, 162.258 nm on the surface of Verm-B2000, Verm-B500, and Verm-B1000, respectively. All the Verm-B products were approved to possess a strong antibacterial activity, with reducing the bacterial growth over 95% in all of the filtration systems containing Verm-B500-2000. The highest log reduction value of 3.47 CFU mL-1 at 96 h was observed for the filtration system containing Verm-B1000. The percentage of silver released from the total Ag in Verm-B500 was 32.36%, Verm-B1000 27.87%, and VermB2000 17.24%; of these amounts, 90.9%, 81.8%, and 75.7% were reabsorbed respectively, by Verm-A. The observed bactericidal efficiency could open an avenue to use silver-impregnated vermiculite in water treatment. Moreover, acid treated vermiculite could be introduced as an affordable absorbent for removal of silver from water filtration system, industrial wastewater and reduce metallic environmental contaminant

This study provides fundamental information on some key aspects of the reproductive biology of Neogobius caspius</em>, a Caspian Sea endemic, poorly studied Gobiidae fish species. In total, 222 specimens were captured monthly from Noor coastal waters in southern part of the Caspian Sea from April to October 2016, while water parameters (temperature, salinity and pH) were monitored weekly. Gonadosomatic and hepatosomatic indices suggested that the reproductive period of this species was in April to May. Peak of Fulton and Clark’s condition factors appeared in April and May for female and male specimens, respectively, then a declining trend appeared until June that remained constant until the end of October. Absolute fecundity ranged from 418 to 1798 oocytes per individual (mean: 1013±357 (SD) oocytes, n=41), which was highly related to the length and weight of fish and weight of gonads. Oocyte mean diameter ranged 35.85±11.80 µm in immature stage to 1103.86±172.01 µm in mature stage. Five stages of maturity for female and four stages for male specimens were described based on macroscopic features and histological description. N. caspius </em>appeared as an iteroparous and a batch spawner species, producing more than one oocyte clutch in a single reproductive season.