Iranian Journal of Fisheries Sciences
Volume:24 Issue: 2, Mar 2025

Eutrophication phenomenon is a global concern in wetland ecosystems. In the present research, the trophic state index (TSI) was initially determined in four main parts of the Anzali wetland using Carlson's TSI. Then, the key variables driving the eutrophication phenomenon were identified in the wetland using principal component analysis (PCA) and classification tree model (CT). Sampling was conducted monthly at 4 different and main parts of the wetland for one year (April 2019-March 2020). Based on the TSI results, all sampling sites are categorized as a hypertrophic state. However, among the sites, the Pirbazar and Sorkhankol had the highest (88.44) and the lowest TSI (76.86), respectively. The decrease in the ratio of total nitrogen (TN) to total phosphorus (TP) in the Pirbazar (5.54), shipping channel (6.58), and Sorkhankol (9.27) indicated the limitation of TN in these sites. On the contrary, the high ratio of TN/TP in the Abkanar (14.85) indicated the limitation of TP in this section. The low average ratio of the TN to TP in the four different parts of the wetland (9.06) revealed the limitation of TN in the entire wetland. Considering the TSI average in the whole wetland (22.83), it can be concluded that all parts of the wetland are classified as a hypertrophic condition. Based on the PCA biplot (the first component), the most influential factors driving the eutrophication in the wetland were TP, water transparency and chlorophyll-a (chl-a), respectively. According to the CT model’s prediction, water temperature, TP, and water transparency contributed more than other factors to the wetland eutrophication process.

Argyrops spinifer, commonly known as king soldier bream, is a species from the Sparidae family in the Persian Gulf and Oman Sea. This study was conducted to investigate the genetic diversity and demographic structure of the mentioned species based on the mitochondrial cytochrome c oxidase I gene. DNA was extracted using the ammonium acetate method from the caudal fin of 90 samples. The PCR reaction was performed using a pair of primers of the nucleotide sequences of the mitochondrial COI gene, and its PCR products were sequenced. Based on the results, the mean haplotype diversity was relatively high in Bandar Abbas (1.000), Chabahar (0.93), and moderate in Bushehr (0.533). The mean nucleotide diversity was also 0.194 in Bandar Abbas, 0.022 in Chabahar, and 0.0133 in Bushehr. Tajima’s neutrality test and Fu’s Fs index between the studied regions were -1.32 and -0.64, respectively (p≤0.05). The highest FST genetic distance was between the Chabahar and Bushehr populations (0.48). Also, the lowest genetic distance of 0.17 was observed between the Chabahar and Bandar Abbas populations. The results showed the presence of different populations of this genus in the Persian Gulf and Sea of Oman.

Metal oxide nanoparticles are the most widely used compounds among nanoparticles, and the increasing use of nickel oxide (NiO) nanoparticles requires a better understanding of their toxic potential impact on various organisms. Although aquatic organisms are predicted to be the main targets of nanoparticles released into the environment, the toxicity of nickel (Ni), especially NiO nanoparticles, in aquatic organisms has not been well studied. This study aims to investigate the oxidant effect of NiO nanoparticles as well as the antioxidant effect of curcumin-coated chitosan-alginate nanoparticles in the Gold fish (Carassius auratus). In this study, five groups of fish (mean weight 8.65±0.45 g; mean length 5.58±0.33 cm) were used for experiments within 4-week treatments. The study groups were included: (i) control group, (ii) treatment group of NiO nanoparticles, and (iii) 3 treatment groups of NiO nanoparticles+ curcumin-loaded alginate-chitosan nanoparticles. At the end of the study period, liver samples were isolated and collected for oxidative damage. Total antioxidant levels, MDA, glutathione, and antioxidant enzymes–catalase (CAT), glutathione-S-transferase (GST), and superoxide dismutase (SOD) – were measured in all groups. The results showed that NiO nanoparticles decreased the level of total antioxidants while increased the level of MDA in the NiO nanoparticle treatment group, but the groups that received NiO nanoparticles + curcumin-loaded alginate-chitosan nanoparticles had better antioxidant parameters. These results showed strong evidence of induction of cellular oxidative stress due to exposure to NiO nanoparticles as well as the protective effect of curcumin-loaded alginate-chitosan nanoparticles.

Molluscs, especially gastropods are essential to the operations of ecosystems. They serve as the food chain's higher trophic organisms' transporters of contaminants. They are also thought to be sensitive markers of changes in the environment, particularly contaminants like heavy metals and microplastics. Due to the high prevalence of microplastics in both freshwater and marine organisms, microplastics are receiving more attention globally. Still, there is a dearth of knowledge regarding animals found in estuaries. In this baseline investigation, the distribution and abundance of microplastics in Babylonia spirata from Indus Delta, Sindh Pakistan are assessed. The mean abundance of microplastics in Babylonia spirata was 28.81±12.94 items/ind and 16.54±12.53 items/g of tissue. Fibers were the dominant type of microplastics (69%), among which black color (37%) was common. PE (25.8%) was the dominant polymer type of microplastic which was identified by FTIR. Evaluating the degree to which Babylonia spirata were contaminated by microplastics sheds light on the potential use of gastropods as bioindicators for baseline research and monitoring.

The Asian sea bass (Lates calcarifer), also known as barramundi, is a species of great importance in Iran’s aquaculture industry. This fish has been farmed for many years to fulfill the rising domestic demand for fresh seafood and to promote exports. However, bacterial diseases and infections pose a significant threat to the growth of this popular species, leading to substantial losses. This study aimed to investigate bacterial contamination in barramundi at coastal cage farms located in the Bushehr and Hormozgan provinces of Iran, as well as to identify the signs and lesions resulting from these infections. According to the criteria for bacterial infection, 30 fish samples were collected from farms. Necropsies were performed on the collected fish, followed by bacteriological analysis and genotyping using 16S rRNA sequencing. The bacteriological results revealed five bacterial strains, confirmed through agent isolation, biochemical profiling, and 16S rRNA sequence verification. The identified isolates comprised Streptococcus iniae strain SB1 (60%), Streptococcus agalactiae strain 20 (70%), Shewanella algae strain 16 (60%), and Vibrio species such as V. azureus strain N3 (86%) and V. harveyi strain N4 (90%). The identification of bacterial species is crucial for resolving health issues and reducing mortality in farmed barramundi. This study comprehensively identified bacterial pathogens impacting barramundi in Iran. The findings, along with the detection methods and bacterial genotyping techniques used, offer practical insights for future research in this area. Additionally, this study increases awareness among researchers, farmers, and clinicians, facilitating the adoption of effective management strategies in aquaculture practices.

The unique behavior of silver nanoparticles (AgNPs) led to their increasing use in a wide range of products and the high discharge of these particles in the aquatic ecosystem. Regarding little information about the toxicity of AgNPs in the aquatic environment, the prediction of possible environmental hazards is the hot topic of current research studies. This study aimed to investigate the effects of long-time exposure of Asian seabass (Lates calcarifer)‎ to green (using brown macroalga extract) and chemically synthesized ‎AgNPs on oxidant/antioxidant and immunological responses. The LC50 of both synthesized AgNPs was determined on fish (mean weight: 15±2.2 g) after 96 h (LC50 for green synthesized AgNPs= 18.27 mg/l and for chemical synthesized AgNPs= 1.32 mg/L). Fish were exposed to green and chemical synthesized AgNPs concentrations of 0 (control), 5, 10, and 25% LC50 for 60 days. For each treatment, 90 juveniles (22±1.5 g) were distributed in fiberglass tanks (300 L) and fed for 60 days. Fish were sampled at 1, 30, and 60 days after exposure. The liver tissue of fish samples was isolated and homogenized and then the activity of catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH), and malondialdehyde (MDA) was determined. The complement pathway activity (ACP), total immunoglobulin (Ig), total protein, albumin (ALB) ‎concentration, and globulin (GLO) were measured in fish blood samples. The results showed that green synthesized ‎AgNPs first ‎increased the activity of the antioxidant system and then significantly reduced its activity. However, after exposure to chemically synthesized AgNPs, ‎the activity of the antioxidant system showed a significant decrease. Both green and ‎chemically synthesized AgNP exposure caused an increase in proinflammatory activities and ‎immune proteins, and these activities were more ‎pronounced after exposure to green-synthesized AgNP.

Fish species can be identified based on the analysis of morphological indices including basic dimension parameters and shape index. Several pattern recognition methods have been proposed to classify fish species through the morphological characteristics of otolith outlines. Machine learning methods have been applied in various fields, particularly in the differentiation of object shapes. Applying machine learning models to identify species based on basic dimension parameters and shape index of otoliths is highly promising. The purpose of this study is to apply machine learning models to classify marine fish species, aiming to determine which machine learning model and indices are suitable for otolith shape classification. A total of 720 samples of left otoliths (sagittae) from 12 fish species, with 60 individuals per species, were used to develop and evaluate the identification model using Python language. For the first time, a comparative evaluation of six machine learning models and three deep learning models was conducted to distinguish 12 fish species in the nearshore areas of northern and central Vietnam. The results of this study have identified machine learning and deep learning models based on high-performing basic dimension parameter (BDP) and/or shape index ShI indices for species identification. This lays the groundwork for developing software for automatic species or population identification based on otolith morphological analysis.

In this study, the effects of various algal resources on water quality, growth performance, body fatty acid composition, and intestinal bacteria of Nile tilapia were studied under a zero-water exchange biofloc system. Oreochromis niloticus with an initial mean weight of 2.73±0.27 g, was cultured in five experimental tanks (150 L) including the control group (T1), biofloc group (T2), biofloc+ N. oculata group (T3), biofloc+ I. galbana group (T4), and biofloc+algal (T5) for 60 days. A total number of 225 O. niloticus was used for this study (15 individuals in each replication). The results showed the highest total ammonia nitrogen (4.54±0.05 mg L-1) in the biofloc treatment (p<0.05). There were significant differences in the growth performance among the control group with other treatments (p<0.05). In terms of fillet quality, the highest amount of saturated fatty acids (39.79±0.25%) was found in the biofloc group. The highest monounsaturated fatty acids (41.87±0.99) and polyunsaturated fatty acids (33.25±0.93%) were obtained in the biofloc+algal treatment (p<0.05). All intestinal bacteria in the biofloc group were higher than the control group (P<0.05). The current study demonstrated that biofloc could promote the growth performance of unsaturated fatty acids in the fish fillet.

This 14-day trial was conducted on 24 Persian sturgeons with a mean weight of 300 g. The treatments consisted of the control group (no cadmium), treatment 1: 200 µg/L of dissolved cadmium, treatment 2: 400 µg/L of dissolved cadmium, and treatment 3: 800 µg/L of dissolved cadmium in triplicates. Results showed that the expression level of metallothionein (MT) at 200 μg/L on the first day was 1.06±0.02, which increased to 2.51±0.13 in the control with prolonged exposure until the fourteenth day. The rate rose from 1.43±0.19 on the first day of exposure to 2.60±0.36 folds the control by the seventh day at a concentration of 400μg/L. Moreover, the expression level at the concentration of 800 μg/L rose from 1.1±0.13 on the first day to 2.15±0.09 folds in the control on the fourteenth day. The results also indicated that the highest level of MT expression (2.60±0.36) was observed in Treatment 2. Accordingly, all three concentrations of dissolved cadmium (200, 400, and 800 µg/L) significantly increased the MT expression on the last day of the trial (p<0.05 and p<0.01). Therefore, MT can be considered a biomarker of cadmium exposure in Persian sturgeons. This study also demonstrated that the MT expression was increased in the kidney tissue of the samples with longer times of exposure to cadmium, but it did not increase by increasing cadmium concentration. Hence, the length of cadmium exposure can affect the kidney MT expression level of Persian sturgeon.

Six species of the Ponyfish species (Leiognathidae) from five genera were investigated for osteological phylogeny analysis from coastal marine waters of the Northern Persian Gulf and Oman Sea. Five specimens of each species were cleared and stained for detailed osteological examination. Additionally, Diapterus auratus was selected as an out-group for comparative analysis. The resulting data matrix was analyzed to reconstruct the phylogenetic tree. Through parsimony analysis, the studied species were classified into two main clades. The first clade comprised Nuchequula gerreoides + (Aurigequla fasciata + Karalla daura). The second clade included (Deveximentum mekranense+Deveximentum ruconiu)+in Photopectoralis bindus. Results were congruent with previously reported molecular phylogenetic analysis and underscored the significance of osteological features in distinguishing taxonomic groups within the Leiognathidae family.

In Iran, rainbow trout is the sole species of cold-water fish that is farmed, and it plays a crucial role in the aquaculture industry. However, challenges like poor environmental conditions, high stocking densities, and inadequate diets lead to stress and weakened immune systems, resulting in reduced growth and increased susceptibility to various diseases. Traditionally, antibiotics have been used to control infections, but their widespread use has resulted in drug residues, health risks for consumers, antibiotic-resistant strains, higher production costs, and environmental degradation. The growing demand for eco-friendly products has intensified the need to limit or ban antibiotic usage in aquaculture. Over the past two decades, interest in utilizing medicinal plants to prevent and treat aquatic diseases has increased. The herbs can help combat antibiotic resistance, eliminate drug residues, and maintain microbial balance in aquatic environments. In this review, we assess the effectiveness of native Iranian medicinal plants on growth, immunity, blood and serum and antioxidant indices, and resistance to microbial diseases in rainbow trout. We also explore how factors such as type of plant material, dosage, duration of use, and pathogen type influence treatment efficacy. Our findings indicate that diets enriched with these plants significantly improve growth, immunity, and disease survival, regardless of the variables considered. This study highlights that plant-based supplements derived from native Iranian herbs offer a versatile alternative for fish farmers, from small-scale to industrial operations.

Marine seaweeds are sources of bioactive compounds such as novel anticancer components. This study investigated the phytochemical composition, antioxidant, and anticancer activities of aqueous and methanolic extracts of three brown algae (Sargassum obtusifolium, Padina gymnospora, and Cystoseira indica) from the Persian Gulf. The contents of total polyphenols, total flavonoids, and total carbohydrates were determined. The antioxidant activity of the extracts was determined by DPPH method. The cytotoxicity of extracts was evaluated using the MTT assay on breast cancer (MCF7) and lung cancer (A549) cell lines. The aqueous extracts had higher levels of polyphenols, flavonoids, and carbohydrates (ranging from 125±11 to 202±19 mg/g) than methanolic extracts (ranging from 43.8±3.4 to 76.6±6.9 mg/g). At 50 µg/mL, the inhibition of DPPH radical ranging from 40.9±0.6 to 62.3±1.4% with an IC50 ranged from 60.9±0.5 to 30.4±0.4 µg/mL. The MTT cell proliferation assay confirmed a significant reduction in MCF7 cell line viability in the methanolic extracts at 390 µg/mL and 190 µg/mL compared to the control group. The methanolic extract of S. obtusifolium showed the highest selectivity index on MCF7 and A549 cells (1.16±0.19 and 1.77±0.16 respectively), despite containing lower levels of phytochemicals than the aqueous extracts. The findings suggest that the methanolic extract of S. obtusifolium exhibits selective cytotoxicity against MCF7 cells. Also, the aqueous extract of C. indica shows an adequate antioxidant index, usable in nutritional science.

The effect of fishmeal (FM) replacement with Spirulina (Arthrospira platensis) meal (SPM) was investigated in Asian seabass (Lates calcarifer) diet. Dietary FM was replaced with SPM at 5 (SP5%) and 10% (SP10%) and a diet without SPM served as the control group. One hundred and thirty five L. calcarifer juveniles (45.0 ± 0.2 g) were randomly distributed into nine 300-L circular polyethylene tanks (15 fish/tank). SP10% group had the highest final weight that was associated with better feed conversion ratio value. A higher gut amylase activity was observed in SPM-treated groups than the control group. SP5% group had a higher gut trypsin activity than other treatments. The liver superoxide dismutase activity in SP5% was higher than the other groups. The liver reduced glutathione level increased with increasing SPM level in the diets. The plasma lysozyme activity in SP10% group was higher than other groups. The plasma cholesterol and alkaline phosphatase contents decreased in the fish fed with SP5%. The plasma aspartate aminotransferase decreased in the fish fed with SPM-supplemented diets. Based on the above-mentioned findings, dietary FM replacement with SPM at 10% is recommended for growth and improving health status in L. calcarifer juveniles.

The sea cucumber, Holothuria scabra (sandfish), is an important aquaculture species due to its high economic value. This has led to over-exploitation causing population decline; consequently, aquaculture of sea cucumber is required to increase production. This study aims to obtain data and information on the growth performance of sandfish reared in a sea pen culture system and develop its cultivation in coastal areas of Sumberkima Village, Gerokgak District of Buleleng, Bali-Indonesia. Three 10 x 5 m2 sea pens (KJT), namely KJT-A, KJT-B, and KJT-C, with a 3-m height net, were installed at the site using bamboo and plugged into the seabed to support the net. These three KJTs have different seafloor characteristics from the experimental group. The sediment composition in the KJT-B consisted of loamy sand with high organic matter compared to KJT-A and KJT-C, which were sandy. The sandfish juveniles were stocked into each KJT at a density of 300 individual/pen with an average initial weight of 17.7±6.6 g and an average total length of 6.6±1.2 cm for 180 days. The results showed the daily growth rate of sandfish in KJT-B was the highest (1.44 %/day) when compared with KJT-A (0.92 %/day), and KJT-C (0.96 %/day). These results indicated that the growth of sandfish (H. scabra) depends on the structure and composition of the seafloor sediment. The seafloor sediment structures of loamy sand with high organic matter and C-organic content promote the best growth of sandfish.

Vibrio parahaemolyticus, autochthonous to marine and estuarine environment, is responsible for foodborne outbreaks associated with seafood. In the present study, a total of 52 V. parahaemolyticus strains isolated from various food contact surfaces in seafood pre-processing units located in Cochin were screened for antimicrobial resistance, virulence and biofilm forming capability as part of risk assessment. Multidrug resistance (MDR) was detected in 94.23% of the strains with higher resistance to ampicillin and colistin. Virulence related trh and tdh genes were present in 30.76% and 3.84% of the isolates, respectively. Among the T3SS genes, T3SS1 and T3SS2β were present in 75% and 23.07% of the isolates and none of them harboured T3SS2α genes. Among the strains, 86.54% of them were biofilm producers. V. parahaemolyticus showed significantly (p<0.05) moderate positive correlations (0.4<r</rthe presence of biofilm-forming MDR V. parahaemolyticus strains with virulence potential on food contact surfaces, thereby emphasizes the need for continuous monitoring of foodborne pathogens and for improving seafood safety in food processing facilities and retail environments.