Iranian Journal of Fisheries Sciences
Volume:21 Issue: 4, Jul 2022

Based on the climate hydrology, ecological biogeography, and land–sea interaction relationships, Vietnamese coastal waters can be separated into three coastal zones. In this study, we analyzed the Johnius carouna (Cuvier, 1830) shape of sagittae from several areas along the Vietnamese coast. The morphometric characters of the otoliths were used to identify stock among the fish of different geographic areas. A multistatistics analysis of otolith shapes was applied to estimate the differences between the three regions. Based on the shape indices, wavelet transform and Elliptic Fourier Descriptors (EFD) have signals for division into three groups of otolith shapes (discriminant analysis for wavelet transform: Wilks=0.065, p<0.001 training misclassification error 9.8%; discriminant analysis EFD:  Wilks=0.059, p<0.001 accuracies of the classification equal 93.75%; analysis of variance on shape indices: p<0.05) of the otoliths for the three locations. This study inferred that two distinct stocks were identified, namely Cat Ba and Tho Chu. The individuals from the central zone (Phu Yen) may be a mixing zone between the north and the south, with two possible populations of Cat Ba and Tho Chu.

A three-dimensional physical-biological numerical model namely ROMS was employed to investigate seasonal variations in biological parameters of Persian Gulf. The model domain included entire Persian Gulf and Sea of Oman. The model has run with climatic data. Lateral and surface boundary conditions were prepared from COADS and WOA09, respectively. The ROMS hydrodynamics model was coupled to bio-Fennel biological model including seven state variables (N2PChlZD2). After ten years’ successive run, numerical results reached a quasi-steady-state and results of the tenth year were used for analysis. The model results revealed area of phytoplankton blooms and were in good consistency with surface chlorophyll data obtained from GMIS archive. The results showed two different peaks of chlorophyll growth in the region. The first peak occurred in spring in northwestern part of Persian Gulf where the blooms begin to grow up and expand to the middle and eastern parts of the region, and the second one occurred in late summer and early autumn in middle and southern parts. The results showed that the amount of chlorophyll in northwest and southern coastal waters was higher throughout the year in comparison to other parts of Persian Gulf, while in deep regions the role of eddies and residual currents are important in changing chlorophyll concentrations. In addition, the model showed that seasonal changes of biological parameters in Persian Gulf were nearly independent of Sea of Oman, and there was a significant relationship between biological parameters variations and seasonal changes of the region.

To compare the fecundity of common carp in relation to their genetic variations in Guilan and Mazandaran provinces, sixty fish samples with 4-5 maturity stages cached from Guilan and Mazandaran provinces, 30 samples obtained from each interval during February 2018 to November 2018. DNA was extracted by phenol-chloroform method and investigated for 11 microsatellites loci. The mean of body weight, total length and age for Guilan and Mazandaran samples were 4.22±0.99 and 3.13±0.30 kg, 57.33±4.68 and 60.93±3.90 cm, 3.80±0.38 and 3.50±0.51 years, respectively. The mean absolute and relative fecundity of Guilan and Mazandaran samples were 239900±57921.67 and 139900±23008.76 as well as 57629.31±5583.58 and 43568.639±2129.45, respectively. The mean body height and eggs diameters measured were 17.50±2.06 and 14.60±1.42 cm as well as 0.759±0.11682 and 0.640±0.4291 mm, respectively. The mean of fecundity increased with increment of fish fork length, body weight and age. There were significant differences in fecundity rate between Guilan and Mazandaran samples. The results showed that the range of allele’s number, expected and observed heterozygosity were 11-18, 63%-86%, respectively. The Fst and Rst values were significantly different between fish populations in Guilan and Mazandaran provinces. These differences may be due to broodstocks transportation by farmers. Tree investigated loci showed significant deviations from Hardy-Weinberg Equilibrium (p<0.05), mostly due to the excess of heterozygosity of Mazandaran samples. The Fst value and Gen flow due to number of alleles were 14.5 and 2.11. So it can be concluded that there were significant differences between number of alleles and genetic diversity in Guilan and Mazandaran.

This study aimed to examine the effect of fatty acid in the diet on changes the incidence of the Red-head Syndrome under temperature stress and hypoxia in white leg shrimp (Litopenaeus vannamei) during 8 weeks. For this purpose, shrimps were fed  by 4 diets  (diet 1: containing 7.02% of total fat; diet 2: containing 6.41% of total fat; diet 3: containing 8.05% of total fat; diet 4: containing 6.41% of total fat with 1750 mg/kg of vitamin E), under 3 stressors (S1: no challenge to environmental stresses; S2: with hypoxic stress (2.0±1.0 ppm); S3: with increasing temperature stress (36±2°C). The results of the hypoxic stress on the incidence of redness in L. vannamei fed with different levels of fatty acids showed that there were differences significantly (p<0.05). Temperature increase although showed no differences between healthy shrimps(p>0.05) but, there were significant difference among red-headed shrimp in treatment 1, 2 and 3 (p<0.05). The examination in treatments 2 and 3 showed hepatopancreatic  were loss the columnar structure so thatelongated cells and dilated tubules were observed. Some B cells had no vacuoles and were not fully developed. The number of R cells was low and basophilic F cells were convex. In treatment 4, the cells have few reserves and were normal. Some B cells were degenerated. The height of the tubules was lower than normal, but no inflammatory reaction was observed in the tissue. In treatment 4, cell showed  better conditions than treatments 2 and 3. Accordingly, B cells were present well and R cells showed moderate storage. In general, it can be concluded that the use of vitamin E can reduce the complication of redness and minimal cell damage to hepatopancreatic tissue in L. vannamei.

The abundance, distribution, and species composition of phytoplankton were investigated in Chabahar Bay located in the Gulf of Oman during 2016-2017. The number of 114 phytoplankton species belong to 4 main phylum (Bacillariophyta, pyrrophyta, Cyanophyta and Chromophyta) were identified of which the most dominant phytoplankton group was pyrrophyta with a relative abundance of 94%. A significant difference of the density of phytoplankton between different sampling months was observed (non-parametric Kruskal-Wallis analysis, p≤0.05). Clear alignment between phytoplankton abundance and nutrient contents was observed during study period. The results showed that increasing the concentration of nutrients by the mid-autumn resulted in phytoplankton blooms. Noctiluca scintillans blooms were observed in October, January and February with the highest abundance in February while, disappeared in the rest of the sampling months. The maximum values of nutrients were observed in Oct (0.73, 5.59 and 3.66 µM of phosphate, nitrate and silicate, respectively) followed by a sharp decrease during Jan and Feb which is probably due to the phytoplankton blooms started from Oct. Diatoms (Bacillariophyta) with a relative abundance of 5.3%, were present in all sampling times with the minimum and maximum abundance in October and February, respectively.

The predatory Bdellovibrio is considered one of the most promising probiotics in aquaculture. Yet the effect of dietary Bdellovibrio probiotics on Chinese mitten crab Eriocheir sinensis has never been evaluated. In the present study, a fifty-day feeding trial was conducted to assess the effects of dietary Bdellovibrio powder at a recommended final dose of 7.5 g kg-1 diets on non-specific immunity, antioxidant ability and disease resistance of E. sinensis. The results indicated that compared with the control, the activities of lysozyme, superoxide dismutase, catalase, acid phosphatase, and alkaline phosphatase were significantly increased in the serum and hepatopancreas of E. sinensis fed with Bdellovibrio powder-supplemented diets (p<0.05). Besides, a significant reduction of malondialdehyde level was also observed in the serum and hepatopancreas of Bdellovibrio powder-fed crabs (p<0.05). In addition, the test crabs fed diets with Bdellovibrio powder for fifty days exhibited significantly (p<0.05) higher protection against aeromonasis, showing a relative percentage survival of 81.25% against Aeromonas veronii challenge for seven days. To conclude, dietary supplementation of Bdellovibrio powder for fifty days can increase immunity, antioxidant capability and resistance of E. sinensis to A. veronii infection.

Replacing fish meal by convenient and economic sources is necessary for sustainable development of aquaculture industry. The present study was designated to explore the effect of different processed canola meals as fish meal replacement on growth performance, digestive enzymes activity, immune parameters, and liver antioxidative status of Nile tilapia Oreochromis niloticus. Four isonitrogenous and isoenergetic diets were used with, (1) no canola meal (control), (2) 25% non-processed canola meal (CM), (3) 25% dephytinized (using 2000 IU/kg phytase) ammonia methanol solution treated canola meal (CPM), and (4) electron beam irradiated (15 kGy) ammonia methanol solution treated canola meal (ECM). Juvenile male Nile tilapia with an average body weight of 3.5 g±0.1 (n=17 fish per tank) were fed the experimental diets three times a day until apparent satiation for 36 days. Results revealed that the fish fed the control diet showed the highest daily growth coefficient (DGC) (p<0.05). CPM group significantly showed greater final weight and DGC in comparison to other treatments (p<0.05). CRM included diet showed lower FE and PER (p<0.05). In addition, those fish fed control diet with no canola meal content showed significantly higher feed intake, followed by CPM contained diet (663.7±9.2 g and 477±20.2 g, respectively, p<0.05). Regression analysis also revealed a statistically significant relationship between total feed intake and DGC. Our results also indicated a significant quadratic relationship between dietary glucosinolate content and DGC implying that as dietary glucosinolate content increased total feed intake and subsequently DGC decreased. Regarding dietary protein digestibility (ADCp), there were no consistent results. Regarding digestive enzymes activity, mucosal innate immunity, liver antioxidant enzyme activities and liver tissue malondialdehyde content (MDA) content, there were no significant differences among experimental groups (p>0.05). It is concluded that dietary ANTs contents mainly glucosinolate affected juvenile Nile tilapia growth performance and nutritional indices mainly via reducing feed intake following feeding on diets contained differently processed or crude canola meal.

The aim of the present study in the first stage was encapsulation of peptides produced from hydrolysis of shrimp wastes (by neutrase enzyme) with combined coating of nanoliposome and chitosan in the form of four treatments (NP or peptide-carrying nanoliposomes, NP-CH-0.05, NP-CH-0.1 and NP-CH-0.5 or peptide-carrying nanoliposomes with coating of 0.05, 0.1 and 0.5% chitosan). In the next step, physicochemical and antioxidant properties of the treatments were investigated. The results showed that average particle size and particle dispersity index in different treatments varied from 228.9±4.85 to 436.7±1.08 nm and 0.389±0.01 to 0.453±0.01, respectively. Zeta potential in nanoliposomes shifted to positive values with increasing chitosan concentration and from -62.59±4.36 mV in NP reached to +56.94±3.71 mV in NP-CH-0.5. Encapsulation efficiency improved by adding chitosan to the surface of nanoliposomes and the highest amount was found in NP-CH-0.5 treatment (94.12±3.73%). Evaluation of release profiles of treatments in Simulated Gastric Fluid (SGF) and Simulated Intestinal Fluid (SIF) showed that coating of peptides using nanoliposome and chitosan helped in protecting the structure of peptides and reduce their release rate significantly (p<0.05). Chitosan-coated nanoliposomes showed more antioxidant activity than NP treatment. Also in chitosan-coated treatments, with increasing chitosan concentration, antioxidant activity of the treatments increased significantly (p<0.05). According to the results, coating bioactive peptides with combined coating of nanoliposomes and chitosan is a suitable technique to protect and increase the efficiency of peptides.

In search for bioactive products, three zoanthid species (Zoanthus spp., Palythoa tuberculosa and Palythoa mutuki) were collected from offshore zone of Hengam Island. Three extracts of each zoanthids (methanol, dichloromethane (DCM) and n-hexane) were tested for antifungal and antibacterial activities against certified strains of bacteria (two Gram-positive: Bacillus subtilis, Staphylococcus aureus and three Gram-negative: Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris) and fungi (Candida albicans, Microsporum gypseum, Microsporum canis) through the disk diffusion assay. Cytotoxic activity of these extracts was evaluated against Artemia nauplii. The results showed that 8 extracts (88.88%) of the zoanthids were active against at least one bacterial strain and 6 extracts (66.6%) were active against at least one fungus (the activity against bacteria was moderate). Also, minimum inhibitory concentrations (MICs) of the extracts with desirable (inhibition zone more than 9mm) in the previous stage were assessed. Among the 9 zoanthids extract, 88.88% showed activity against some of the five bacteria, and 66.6% showed activity against some of the three fungi. The most active zoanthid extract against three fungi was dichloromethane extract of the Zoanthus ssp. that showed promising antifungal activity against Candida albicans in vitro models. The minimum inhibitory concentrations and LC50 values of dichloromethane extract of Zoanthus ssp were 125μg/mL and 181μg/mL, respectively. Therefore, this extract can be a candidate for candidiasis therapy.  LC50 of DCM, crude extract of Palythoa mutuki was 31µg/ml, showing high toxicity. This is the first report of biological activities of marine zoanthids from an Iranian Island of Persian Gulf.

Genus Ulva includes edible seaweed species with extensive morphological overlaps, plasticity, and intra specific variation, making it taxonomically difficult to classify. Ulva species occur in the Persian Gulf, and Oman Sea, but there is no detailed information on their genetic structure, diversity, as well as species relationships. Aims of the present study were to: (1) identify existing species of the genus Ulva in selected areas of the Persian Gulf and Oman Sea, and (2) illustrate species relationships by a combination of morpho-anatomical and molecular data. Based on morphological features, 10 Ulva species were identified which were confirmed by their DNA homology with the reported taxa. The Ulva species were delineated using a combination of morphological, anatomical and molecular data (ISSR, SCoT, ITS, rbcL, and tufA region sequences). AMOVA revealed species genetic differentiation and a higher level of intra-specific diversity in Ulva. The species relationship is discussed based on genetic and morphological data. A kind of divergent selection on morphological characters and in response to geographical coordinates is suggested.

Phytoplankton is considered the primary producer of any ecosystem and is sensitive to environmental changes. Therefore, phytoplankton is a suitable indicator for evaluating river water quality. Change of the environment leads to changes in abundance, diversity, and dominance of phytoplankton communities. Six stations were selected from beginning of Arvand River (the point of tributary from Karun River, station 1) to the sea estuary (in Arvand Kenar, station )2015-2016). Phytoplankton sampling was conducted using a plankton net with 30-μm mesh size, with three replications in each station. Meanwhile, temperature, salinity, pH, dissolved oxygen (in field operations), nitrate and phosphate were measured in the laboratory with three replications. The results showed that 43 phytoplankton species were present in the sampling area. Ochrophyta division was most abundant with 32 species, followed by four divisions Chlorophyta (5 species), Cyanobacteria (3 species), Myzozoa (2 species), and Charophyta (1 species). The most dominant species in different seasons were Coscinodiscus marginatus from Bacillariophyceae, followed by Oscillatoria sp. from Cyanophyceae and Ulothrix aequalis from Chlorophyta. Mean total value of diatom trophic index was calculated to be 62.31+3.09 during the study period, indicating poor quality of the ecosystem and eutrophic condition. According to the results of correlation analysis (PCA), phosphate content was one of the most important factors affecting abundance and diversity of phytoplankton.

This research aimed to study the histological effects of the acute water-soluble fraction of diesel (WSFD) on the liver, gill, and kidney of common carp (Cyprinus carpio). The fish were divided into four experimental groups; control (group1) (G1) without WSFD, and three groups of WSFD with densities of 4% (G2), 8% (G3), and 16% (G4). After 48 hours of exposure, sampling of liver, gill, and kidney was performed from all experimental groups, simultaneously. The results showed that the main alterations observed in the gill included goblet cell increasing, epithelial lifting, complete and incomplete fusion, filamentous edema, blood congestion, aneurysm, and infiltration of inflammatory cells causing the rank of gill tissue lesions in the G4 (3.30) and G3 (2.70) significantly differed from the G1(0.00) (p<0.005). Sever sinusoid dilation, sever blood congestion, hypertrophy a of nucleus, nucleus in lateral position, cytoplasmic vacuolization and pyknotic nucleus were observed in the liver. The rank of liver tissue lesions in the G4 (3.30) and G3 (2.70) significantly differed from the G1(0.00, p<0.005). Tubular disorganization, shrinkage and necrosis of tubule, and melanomacrophage aggregation were observed in the kidney. The rank of kidney tissue lesions in the G4 (3.30) significantly differed compared to the G1 and G2 (0.00) (p<0.005). Total lesion rank of whole aforementioned tissues in G4 (9.70) significantly differed from the G1 (0.00) and G2 (3.70) (p<0.05). The results showed that WSFD causes pathological lesions incidence in the fish liver, gill, and kidney and increase in WSFD level causes more severe tissue damages.

Kidneys play an important role in regulating the balance of water and ions in freshwater and seawater fish. However, complex kidney structures impair a comprehensive understanding of kidney function. In this study, in addition to the investigation of renal histology, Na+-K+-ATPase, Na+-K+-2Cl- cotransporter (NKCC), and Na+-H+ exchanger (NHE) were localized in the renal system of Walton's mudskipper (Priophthalmus waltoni). The kidney samples were fixed and they passed the preparing section and staining stages. The renal tubules were composed of proximal tubules and distal tubules, followed by collecting tubes and finally collecting ducts. The distribution of the Na+-K+-ATPase immune response varied in different sections of the nephron. The NKCC positioning was reported only in collecting tubes and collecting ducts, and proximal tubes and distal tubes did not respond to the antibody. Immunohistochemical response for NHE3 localization was detected only at the apex of epithelial cells of proximal tubules and collecting tubes. The distal tubes showed a negative reaction and the collecting ducts showed a weak response to NHE3 immunolocalization. In conclusion, Na+-K+-ATPase, NKCC, and NHE were differentially located in the renal system, suggesting that various physiological system operates in the renal system for ionic retention. This study provided valuable information to understand the ion regulation abilities of epithelial cells in various parts of P. waltoni nephrons.

This study determinated the enrichment effect of rotifers (Brachionus plicatilis) with Algamac 3050, Olio ω-3 and Selco parkle supplemented with L-carnitine on fatty acid composition. Rotifers were enriched with singly or in a combination of commercial products with or without L-carnitine; S. parkle, S. parkle+Algamac 3050, S. parkle+Olio ω-3, S. parkle+Algamac 3050+Olio ω-3, S. parkle+L-carnitine, S. parkle+Algamac 3050+L-carnitine, S. parkle+Olio ω-3+L-carnitine, S. parkle+Algamac 3050+Olio ω-3+L-carnitine. Considerable differences were found in the fatty acid composition of B. plicatilis fed with commercial enrichment diets. The highest EPA, DHA and PUFA were determined in rotifers enriched with S. parkle+Olio ω-3+L-carnitine, S. parkle+Algamac 3050+L-carnitine, S. parkle+Olio ω-3+Algamac 3050+L-carnitine, respectively at 6 hour. The enrichment duration was found to have significant effect on PUFA content of rotifers (p<0.05). This study clearly showed that L-carnitine can be used with commercial products to enrich the fatty acid contents of rotifers in marine fish hatcheries.

During a survey of the Gaawshan dam lake from 2014  to 2015 some specimen  obtained by seasonal sampling in 8 stations . Two different methods were used for sampling; gill net and beach seine. Due to the results 11 species of Cyprinidae  family were identified ,7 species were native and 4  species were exotic. The distribution and  abundance of species were recognized. Squalius cephalus, Capoeta trutta and  Alburnus mossulensis had the most abundance in Gaawshan lake respectively.