Iranian Journal of Fisheries Sciences
Volume:24 Issue: 6, Nov 2025

This study aimed to assess the population structure and genetic diversity of captive Lates calcarifer. The investigation included three cultured cohorts initially imported in 2016, 2018, and 2019 (hereafter termed 96, 98, and 99, respectively) as fry to a Marine Fish Research Station (MFRS) at 12 gene loci. The results indicated that all microsatellite markers were polymorphic in all populations. Across three cohorts, the average allele number was 18.5 per locus with nearly half (49%) of 65 unique alleles detected in cohort 99. The average observed alleles (Na), allele richness (Ne), and Shannon Information index (I) in the whole population were 6.25, 4.22, and 1.54, respectively. The mean observed heterozygosity (Ho) in all three cohorts was obtained as 0.733, which accorded with expected heterozygosity (He). The highest and lowest observed alleles were detected in 99 and 96, respectively. The highest mean Na (7.5), Ne (5.02), and Shannon index (1.72), and lowest mean Na (5.33), Ne (3.67), and I (1.39) were observed in cohorts 99 and 96, respectively. Stock 98 represented the Na, Ne, and I as 5.92, 3.97, and 1.5, respectively. The maximum and minimum Ho belonged to 98 (0.787) and 96 (0.675) cohorts, respectively. The fixation index (F) was low in three cohorts and even showed a negative value in 98 (-0.069). Wright's F-statistics, including FIS, FIT, and FST, estimations were evaluated as -0.01, 0.05, and 0.06, illustrating the non-inbreeding coefficient within the population and overall population and the low coefficient of co-ancestry, respectively. Chi-square tests revealed that all 12 markers conformed to Hardy-Weinberg equilibrium (HWE) in the 98 cohorts. In contrast, cohorts 96 and 99 deviated meaningfully from HWE in one locus (Lca098) and two loci (Lca130 and Lca137) (p<0.01), respectively. Nei's standard genetic distance and Pairwise FST distance between the three cohorts showed the lowest and highest genetic distance between pair cohorts 96-98 and 96-99, respectively. Analysis of molecular variance determined that between-population component of genetic variance (3%) was firmly lower than the within-population component (97%), resulting in meaningful genetic differentiation between populations (FST = 0.033) (p<0.01). Based on the population genetic structure analysis, under the admixture model, the most negligible probability is associated with K=2 in seabass cohorts, meaning two significant distinct genetic structures. We found that these populations in the MFRS may create a base population, a prerequisite for further selective inbreeding programs.

This study investigated the effects of irradiated-propolis (GI-EEP) supplementation on rainbow trout (Oncorhynchus mykiss) during an Ichthyophthirius multifiliis (Ich) challenge, aiming to determine if it could enhance the fish immune system and improve its response against Ich. In this experiment, 150 fish (35.80±3.95 g) were divided into five groups and fed diets containing gamma-irradiated or non-irradiated propolis extracts or no treatment (control) for 60 days. The fish were then challenged with 5000 I. multifilis theronts per fish. Then, five days post-challenge, blood and skin samples were taken for hematological, biochemical, and gene expression analysis. The results showed that 0.5 g kg-1 of gamma irradiated- ethanol extract propolis (GI-EEP) supplementation regulated electrolyte levels, improved blood biochemical parameters, and enhanced the immune system's response in Ich-infected rainbow trout. It increased lysozyme activity, elevated white blood cell counts, and improved red blood cell counts. Supplementation with GI-EEP positively influenced these parameters, including increasing total protein and albumin and decreasing globulin levels. It also elevated alkaline phosphatase activity, indicating improved inflammation control. Gene expression analysis revealed increased levels of inflammatory and immune response markers, including interleukin 8, and immunoglobulin M. No significant changes were observed in C3 complement mRNA gene expression levels. Elevated major histocompatibility complex II mRNA levels indicated an effective immune response. Overall, administering IPE to Ich-infected rainbow trout regulated electrolytes, improved blood parameters, and boosted the immune system's ability to combat the infection. Results showed that the optimal propolis dose for regulating physiological parameters and immune responses in Ich-exposed fish was 30 KGy.

This study was conducted in Iraqi marine waters in the northwest of the Persian Gulf. The data for boats and annual catches were collected from the Al-Nasr Fishing Association Ltd. in Al-Faw and the Basrah Agriculture Directorate, which depend on commercial transaction data for documentation on the 2021 fishing season. The fish landing site in Al-Faw city is in the southernmost of Iraq. The amount of experimental catch per unit of effort (CPUE, kg/hour/boat) was measured during regular monthly trips in 2021. The CPUE for large boats peaked in June (16.66 kg/hour /boat), whereas the highest value of CPUE was recorded in May for demo fishing by small boats employing gillnets (11.8 kg/hour/boat). Shrimp was dominated in the Iraqi catch, constituting 16.13% of the total catch. The commercial transaction data registered by the responsible administration did not agree with the demo fishing results of the estimated CPUE in re-estimating the Iraqi marine catch. The study found a significant flaw in the fish statistics based on the commercial transactions registering data in Iraqi marine catches. The current study also estimated that the unreported artisanal commercial catch in Iraq during 2021 was about 48%, which is higher than other studies in re-estimating the Iraqi marine catch. The study documented a significant decrease in the number of fishermen, with their count reaching (2025) compared to the previous years. Thus, it is necessary to assign an independent authority to document the Iraqi marine catch.

In this study, two probiotics (Citrobacter freundii and Bacillus foraminis) with indigenous quorum quenching (QQ) were isolated from the intestine of Cyprinus carpio and their effects on hemato-serological parameters and innate immune responses, antioxidant capacity and disease resistance in C. carpio were determined. The juveniles (n=450, 50.26±10.47 g mean weight) were randomly divided into 6 groups (with 3 replications) and fed with diets containing 1×109 cfu g-1 of C. freundii (QQ1, G1), B. foraminis (QQ2, G2), Lactobacillus plantarum (without characteristics QQ, WQQ, G3), QQ1+QQ2 (G4), QQ1+QQ2+WQQ (combine, G5), and a control diet (without probiotic) for 60 days. The hematocrit level was increased in the fish fed with QQ1 and WQQ supplemented diets compared to the control group. At 30 days, the combined probiotic treatments (QQ1+QQ2+WQQ) significantly increased hemoglobin and total leukocyte count compared to QQ1 and control, though these differences were not observed at 60 days. QQ2 notably improved complement activity and lysozyme levels after 30 days, while QQ1+QQ2 showed a higher antitrypsin activity at 30 days. The myeloperoxidase levels were elevated in the combined treatments at 60 days. The hepatic catalase activity was higher in QQ probiotic groups at 30 days but it was decreased by 60 days with significant differences noted between WQQ and other groups. The highest superoxide dismutase activity was obtained in QQ2 at 30 and 60 days. The liver glutathione level was decreased in the mixed probiotic groups but it was increased in the combined group at 60 days. A lower content of malondialdehyde was in QQ1 and QQ2 groups at 60 days. The probiotic-treated groups showed significantly lower mortality rates compared to the control against A. hydrophila infection, with the highest mortality occurring 30 hours post-infection [G1 (30.6%), G2 (30.6%), G3 (40.63%), G4 (30.6%), G5 (40.63%), and the control group (60.3%)]. Overall, the indigenous probiotics cause an improvement in various health parameters and could reduce mortality rates in infected fish.

The present study aimed to compare the effects of pituitary extract or Ovulin (containing s-GnRH and anti-dopamine) injection on spermatological parameters, hematological, and serum biochemical characteristics of male Cyprinus carpio var. Sazan. The male broodstocks were caught from the Caspian Sea and transferred to the Sijeval Center of Fish Propagation and Reconstruction of Genetic Reserves of Bony Fish in Bandar-e-Turkmen, Iran. After acclimation, the fish were divided into two experimental groups: one injected with pituitary extract (PT; 2 mg/kg) and the other with Ovulin (OV; 0.25 mL/kg). The blood samples were taken from the fish before and 12 hours after the injections (analyzed by two-way ANOVA); the sperm samples were also collected 12 hours after the injections (analyzed by t-test). The results showed that OV treatment significantly increased sperm pH, motility duration, and spermatocrit percentage, compared to PT treatment. The serum cortisol level was significantly increased in OV treatment after the injection. The serum glucose concentration and erythrocyte count were significantly increased after the injections, whereas the serum cholesterol, total protein, and sodium concentrations significantly decreased. The blood hemoglobin, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin were significantly decreased after the injection. There were no significant changes in blood leukocyte counts, serum potassium, calcium, albumin, triglyceride, and blood mean corpuscular hemoglobin concentration among the treatments (p>0.05). In conclusion, OV treatment serves as a beneficial alternative to PT extract for stimulating final spermatozoa maturation in male Sazan, without causing any health issues.

This study developed and characterized electrospun chitosan/polycaprolactone (CS/PCL) nanofibers incorporating a thyme essential oil (TEO)/zinc oxide (ZnO) nanoemulsion for active food packaging applications. Nanofibers were fabricated via electrospinning, with TEO (3% and 6% w/w) and ZnO integrated through an emulsion method, and compared against a direct mixing approach. Scanning electron microscopy (SEM) revealed well-oriented, smooth, and bead-free nanofibers with average diameters ranging from 60 nm (with TEO) to 88 nm (without TEO). Antimicrobial efficacy, assessed over five days, indicated a time-dependent decrease for most nanofibers. Crucially, nanofibers prepared via the emulsion method demonstrated significantly sustained antimicrobial activity compared to those produced by direct mixing. Specifically, TEO-loaded nanofibers, encapsulated via emulsification, effectively maintained the total bacterial count of packaged meat within the standard range (<6 Log CFU/g) for up to 6 days. These findings highlight the significant potential of electrospun CS/PCL nanofibers incorporating emulsified TEO/ZnO for developing effective antimicrobial food packaging solutions, thereby enhancing food safety and extending shelf life.

Artisanal fishers usually utilize various types of traditional fishing gear, including nets, rods, and traps. Since these choices influence their income, the current study examined how different types of fishing gear affect the income of artisanal fishers on the East Coast of Peninsular Malaysia (ECPM). Data were collected through structured interviews with 262 heads of crew, all of whom were artisanal fishers across Kelantan, Terengganu, and Pahang. A set of questionnaires was used to collect the data from October 2023 to February 2024. Since artisanal fishers are scattered along the ECPM, the researchers used a random sampling technique. Data were analyzed using budgetary analysis and one-way ANOVA. The results indicate that trap fishing yields the highest income due to its ability to capture high-value species with lower operational costs, whereas gillnet and hook-and-line fishing provide moderate earnings. The study underscores the importance of selecting appropriate fishing gear to maximize income while minimizing costs.

The present research evaluated the effects of dietary thiamin levels in low and high-fat diets on the growth performances, body composition, and hematology of Beluga (Huso huso) juveniles. A total number of 480 juveniles with an average weight of 44.98±1.96 g were distributed in 24 tanks and fed with diets containing 180 g/kg fat (high-fat, HF), 180 g/kg fat+7 mg/kg thiamin (HF-7B1), 180 g/kg fat+15 mg/kg thiamin (HF-15B1), 180 g/kg fat+25 mg/kg thiamin (HF-25B1), 90 g/kg fat (low fat, LF), 90 g/kg fat+7 mg/kg thiamin (LF-7B1), 90 g/kg fat+15 mg/kg thiamin (LF-15B1), 90 g/kg fat, 25 mg/kg thiamin (LF-25B) for 8 weeks. At the end of the feeding trial, five fish from each tank were randomly sampled and the blood samples were collected to evaluate hematological parameters. The results showed that dietary fat and thiamin levels had no significant interaction effect on the final weight, weight gain, specific growth rate, feed conversion rate, and survival rate (p>0.05). The fat had a significant effect on growth performance and high-fat diets substantially increased final weight, weight gain, and specific growth rate compared to low-fat diets (p<0.05). Different thiamin levels had notable differences in the growth performance in low and high-fat diets and growth significantly were higher in fish fed with thiamine compared to control group (p<0.05). The interaction effect of fat and thiamine on body composition was not significant (p<0.05). The effect of fat on protein is significant and beluga fed with high-fat diet had a higher protein content than beluga fed with the low-fat diet. There were significant differences in WBC, Hb between treatments and the highest level was obtained in HF-15B1 and HF-25B1 (p<0.05). The results showed that diets supplemented with thiamin improved growth performance, body composition, and hematology index in beluga sturgeon.

The increasing demand and cost of fishmeal, together with seeking more sustainable feed ingredients in aquaculture have pushed the investigation of alternative protein sources, such as earthworm (EW; Eisenia fetida). A 50-day feeding trial was conducted to evaluate the effects of dietary replacement of fishmeal by EW meal on the growth performance, body composition, and survival rate of Pacific white shrimp (Litopenaeus vannamei) postlarvae. Triplicate groups of shrimps (mean weight 0.05 g) were fed with 5 isonitrogenous and isolipidic experimental diets including 0% (EW0; control), 25% (EW25), 50% (EW50, 75% (EW75), and 100% (EW100) EW meal replacing fishmeal. The final body weight, weight gain, and specific growth rate revealed significant differences among the groups, with the lowest values observed in the EW75 and EW100 groups compared to the control group (P<0.05). However, the incorporation of the 25% and 50% EW meal in the shrimp feed had the highest survival rates and also increased their capacity to convert feed into shrimp biomass. The proximate analysis indicated that 25% and 50% of fishmeal could be replaced with EW meal without any negative effects on the protein and lipid content of the shrimp carcass. Obtained results indicate that optimum replacing up to 20% of fishmeal with E. fetida meal in the diet of Pacific white shrimp (L. vannamei) does not negatively impact growth performance, survival, or body composition.

This research investigated the effects of dietary cobalt chloride (CoCl2) and ascorbic acid (AA) on growth, physiological, and molecular parameters in Siberian sturgeon (Acipenser baerii). Two hundred seventy juveniles were divided into eight groups fed diets containing 2 or 4 mg/kg CoCl2 and 200 or 800 mg/kg AA for 12 weeks. Results showed significant differences in final weight, length, weight gain, and growth rate among treatments (p<0.05), indicating differences when compared to the control group. However, no significant difference was observed in specific growth rate, condition factor, Average daily growth, or protein efficiency ratio compared to the control (p>0.05). The lowest and highest AA/cobalamin levels were found in the control and the 4 mg/kg CoCl2 with 200 mg/kg AA, and the 2 mg/kg CoCl2 groups, respectively (p<0.05). Maximum serum iron level was observed in fish fed 800 mg/kg CoCl2, and the lowest glucose was in the control (p<0.05). The cortisol level was significantly higher in 2 mg/kg CoCl2 with 200 mg/kg AA group compared to the control, which had the lowest levels (p<0.05). The highest hsp70 and p450 gene upregulation, as well as the highest GH and igf-1 expression, occurred in the 4 mg/kg CoCl2 with 200 mg/kg AA group, with the lowest expression in the control (p<0.05). Overall, 4 mg/kg CoCl2 and 200 mg/kg AA supplementation had more positive effects on growth performance, hematological and biochemical indices, and the modulation of genes associated with growth, stress response, and immunity in Siberian sturgeon.

This study successfully determined the chromosome numbers and karyotypes of two marine fish species from separate families using the short-term culture method (PB-MAX™ application). The culture incubation periods varied for each species. Kidney tissues from the fish samples were treated with PB-MAX™ for either 2.5 or 4 h. Results showed that diploid chromosome numbers, karyotypes, and arm numbers differ by species: Red Mullet, Mullus barbatus, has 2n – 44, with 3 pairs of metacentric, 7 pairs of submetacentric, 7 pairs of subtelocentric, and 5 pairs of acrocentric chromosomes (NF=64). Round Goby, Neogobius melanostomus, has 2n – 46, consisting of 46 pairs of acrocentric chromosomes (NF=46). C– and NOR–positive results were achieved through constitutive heterochromatin banding and silver nitrate staining for both species. The primary objective of this research is to demonstrate the applicability of short-term culture in producing successful cytogenetic results in marine fish. This study will support future research and facilitate chromosome studies on marine fish, making the process quick and practical.

The increasing prevalence of antibiotic resistance has led researchers to search for pharmaceutical products that can replace antibiotics or be used in combination with them. Among natural compounds, brown algae extract can have inhibitory effects on bacteria. In the present study, the effect of Sargassum glaucescens extract on virulence gene expression and its anticancer potential was investigated. Stool samples were collected from gastrointestinal infection individuals referred to Imam Khomeini and Milad Hospitals in Tehran from March 21, 2022, to September 21, 2022. Salmonella typhi isolates were identified using phenotypic and chemical tests. Next, Vir gene was confirmed through a polymerase chain reaction (PCR). In the next step, the minimum inhibitory concentration (MIC) of the methanolic extract of S. glaucescens was determined. Furthermore, the expression level of Vir, P53, and Bcl-2 was investigated using the Real-Time PCR method. Among 110 collected samples, 60 isolates of S. typhi were identified, all of which had the Vir gene. The MIC of the methanolic extract was S. glaucescens 16 μg/ml. The expression level of Vir and Bcl-2 in Caco2 cells infected with S. typhi, and treated with S. glaucescens extract was significantly decreased (p˂0.001). Besides, the expression level of P53 showed a significant increase (p<0.0001). The obtained results showed that the methanolic extract of S. glaucescens has strong anti-bacterial and anti-cancer effects.

The potential of using poultry by-product oil as a partial replacement for fish oil in the diets of young beluga sturgeon (Huso huso) (initial body weight, 270.6 ± 8.4 g) was studied. Three experimental diets with different levels of fish and poultry by-product oil were formulated as: 100% fish oil (FO), 100% poultry by-product oil (PO), and a blend of equal amounts of fish and poultry by-product oils (FPO). All diets were isoproteic (30% DM) and isolipidic (12% DM). After 8 weeks of feeding, the condition factor was significantly lower in the fish fed with FPO than in the fish oil group (p<0.05), whereas no significant differences were observed in body weight gain, feed conversion ratio, specific growth rate, protein productive value, protein efficiency ratio, crude protein, crude fat, ash, and moisture among treatments. Furthermore, the liver and viscera fat of the fish fed with PO were significantly higher than those of the other treatments (p<0.05). The results indicate that poultry by-product oil can effectively replace up to 50% of fish oil in the diet of young beluga sturgeon (as in the FPO treatment) without adversely affecting growth performance, body composition, or nutrient utilization.

Several viruses cause devastating mortality in economically crucial shrimp species, including Penaeus monodon, Litopenaeus vannamei, and L. stylirostris. In this context, the white spot syndrome virus (WSSV) is a highly contagious lethal, stress-dependent virus, which belongs to the family Nimaviridae, genus Whispovirus, and it is responsible for deadly WSSV affecting the shrimp industry worldwide. This virus possesses a large, circular, and double-stranded DNA genome that varies in sizes (292.9–307.2 kb), where different isolates exhibit differing levels of virulence. The spread of the infection through horizontal transmission may be related to the infected shrimp and carriers such as other crustaceans, seabirds, aquatic arthropods or other vectors. There are various managerial responsibilities including biosecurity measures and the implementation of vaccination programs to control the spread of WSSV in the aquaculture shrimp sectors. There are still many challenges in the management of this disease. Probiotics and immunostimulants show promise methods for controlling WSSV. Additionally, New strains of WSSV are emerging, posing a serious threat to the shrimp aquaculture due to their genetic variation and differing virulence levels, which all complicate existing disease control strategies. This review provides an overview of the current knowledge on the biology and pathogenesis of white spot disease (WSD), including the mechanisms involved in viral replication, host immune response, epidemiology and disease progression. Moreover, it discusses the various management approaches that have been developed for the control and prevention of WSD in the shrimp aquaculture industry and also highlights the challenges faced in the management of WSD and the potential future directions for research in this field.