Iranian Journal of Fisheries Sciences
Volume:24 Issue: 5, Sep 2025

The absorption or accumulation of metals by the organisms of an ecosystem will have a different effect on their food chain. This research compares the heavy metal absorption of copper and chromium in algae, amphipods, and sturgeon species. In Materials and Methods respectively, included the preparation stage including algae cultivation, catching and propagating gammarus and fish and the digestion stage including initial digestion by nitric acid and the final digestion by Header Digest. In this research, algae had a better efficiency in chromium absorption at the initial time. A significant difference was observed in the absorption of algae between copper and chromium (p<0.01). On the contrary, gammarus had a better efficiency in copper absorption, and the absorption process increased during the time. A significant difference was observed in the biosorption of gammarus between heavy metals copper and chromium (p<0.01). The accumulation of heavy metals in the liver was more than in muscle. There was a significant difference between fish tissues in the accumulation of heavy metals (p<0.01). In body tissue, copper accumulates more than chromium. A significant difference was observed, the comparison between the accumulation of copper and chromium metals in fish tissues (p<0.01). The highest absorption and accumulation of metal was observed by algae and gammarus respectively, in fish body tissues. Algae are strong metal absorbers from the environment and remove metal from the fish body. Gammarus absorbs the metals from the environment and transports them to the fish body. The absence of Spirulina algae in the coastal ecosystem of the Caspian Sea causes the direct transfer of heavy metals to small organisms such as gammarus, and the consumption of these organisms by fish will have harmful effects on their health and ultimately on humans.

This study investigated the effects of biofloc technology (BFT) on water quality, productivity, and intestinal microbial diversity in Far Eastern catfish and Japanese eel. A total of 450 Far Eastern catfish or 50 Japanese eels were housed in separate tanks during a 4-week experiment that compared BFT and the control group. The ammonia nitrogen (NH₄⁺-N), nitrite nitrogen (NO₂⁻-N), and nitrate nitrogen (NO₃⁻-N), along with the growth performance and the gut microbial diversity indices were evaluated. Post-breeding, NH₄⁺-N and NO₂⁻-N levels were consistently maintained below 1 mg/L in BFT tanks, while NO₃⁻-N levels exhibited continuous increases. Compared to the control group, BFT tanks showed superior growth metrics for both species, particularly Far Eastern catfish, which displayed significantly higher values for body length, body weight, and stocking density (p<0.05). Principal coordinates analysis revealed notable similarities in microbial communities across treatments. The Firmicutes phylum was predominant in the gut microflora of both fish, while Proteobacteria, Bacteroidetes, and Fusobacteria predominated in the breeding water. The Firmicutes/Bacteroidetes ratio increased in BFT group, suggesting a positive impact on growth. Operational taxonomic units ranged from 94 to 293 for Japanese eels and 234 to 353 for Far Eastern catfish. Based on Venn diagram analysis, 36 to 75 unique species were identified in Japanese eel gut samples, while Far Eastern catfish gut samples contained 72 to 145 unique species. In conclusion, BFT positively impacts water quality, fish growth, and beneficial intestinal microbes.

This study provides detailed information on the population structure, growth, mortality, probability of capture, and longevity of the Deep-water rose shrimp (Parapenaeus longirostris, Lucas 1984) along the coast of Ghana. A total of 1,164 specimens were collected monthly from July 2020 to June 2021. The mean total length of the species was 9.72±2.22 cm. The length-weight relationship, in log-transformed format, was Log BW=2.841 Log TL–2.109, indicating a negative allometric growth pattern. The Von Bertalanffy growth parameters for total length were estimated as L∞=17.85 cm TL, t₀=-0.21, and K=0.87 year⁻¹. The critical length at capture ratio was 0.56, suggesting potential growth overfishing due to intensified fishing efforts. Natural and fishing mortality rates were 1.84 per year and 1.98 per year, respectively. The exploitation rate was 0.52, indicating relatively optimal exploitation of the stock along the coast of Ghana. Continuous monitoring and extended closed seasons are some of the recommended management measures required to enhance the sustainability of the sampled species in the coast of Ghana.

The objective of this study was to analyze growth and mortality parameters, growth patterns, and sex ratios of blue swimming crabs (BSCs) for the population management policy in Southeast Sulawesi waters. The samples were collected weekly at Pamandati, Bungin Permai, and Kasipute mini plants from July to September 2023. Growth parameters were relatively similar to other tropical waters, but total mortality was high. The exploitation rate (E) was generally low (E< 0.5), except in Pamandati (E = 0.58). BSCs exhibited negative allometric growth (b<3), with carapace width (CW) contributing >55% to weight (W). Poor environmental conditions of BSC habitat were indicated by a negative condition factor. Efforts to maintain the sustainability of BSCs population while providing high economic and social value suggest that BSCs exploitation can still be increased until reaching E=0.5, but BSC females should outnumber males to support reproduction. Juveniles (<10 cm CW) and spawning females should be protected, and mangrove habitats preserved. This study supports and strengthens sustainable BSC management in Indonesia.

Skipjack tuna (Katsuwonus pelamis) represents an essential fishery resource in the waters off Malang's South Coast in East Java, possessing significant economic and ecological importance. However, escalating fishing pressures and climate variability, particularly fluctuations in sea surface temperature (SST), have raised concerns about the sustainability of its stock. This research aimed to evaluate the fishing vulnerability and population dynamics of skipjack tuna in the area. Data was gathered from January 2021 to October 2021 at the Pondokdadap Coastal Fishing Port (CFP) Malang South Coast Waters, involving the analysis of 1,062 skipjack tuna. The Productivity and Susceptibility Analysis (PSA) was utilized to assess vulnerability, while growth, mortality, and recruitment patterns were examined through length-frequency distribution and the von Bertalanffy growth model. The findings revealed that skipjack tuna had a productivity score of 2.44 and a susceptibility score of 2.33, resulting in a low vulnerability classification (1.44). Nonetheless, the species faces overfishing, as indicated by an exploitation rate (E=0.58) surpassing the sustainable threshold of 0.50. The relationship between SST and catch per unit effort (CPUE) and recruitment patterns showed a low to moderate inverse correlation, indicating that environmental factors affect stock variations. To promote sustainability, it is crucial to implement effective management strategies, including regulations on fishing efforts, size restrictions, and seasonal closures. Adopting ecosystem-based fisheries management (EBFM) approaches incorporating climate adaptation strategies is also advisable. These results offer important insights into the interplay between SST dynamics and skipjack tuna fisheries, aiding future stock management and conservation initiatives.

The Nemipteridae fish family is a colored marine fish species having elongated bodies and filamentous dorsal fin extensions. They are widely distributed in the Indo-Pacific Oceans and prefer to live in shallow coastal waters, often over muddy and sandy bottoms. This fish family has economic value in Southeast Asia and is widely consumed as food. In this study, we conducted the DNA barcoding of the Nemipteridae fish family. Five different species of Nemipteridae were taken from the marine waters of Pakistan. A total of 33 specimens belonging to five species and three genera were collected from 2019 to 2023. This study delineated two cryptic species (Nemipterus japonicus and Nemipterus randallii) on the molecular basis. The phylogenetic tree was made and showed genus-wise clustering of the species. A clear sister clade was able to be seen within the N. japonicus and N. randalli, Moreover, the barcode gap showed a significant genetic gap between these species, validating them as separate species. The present study of DNA barcodes has demonstrated high efficiency in the identification of species. This is the first study that explores the genetic basis of the family Nemipteridae from the coastal area of Pakistan.

This study aimed to evaluate the therapeutic potential of siam weed (Chromolaena odorata) leaves meal (SWLM) on the growth performance, reproductive indices, intestinal morphology, and blood profiles of African sharptooth catfish (Clarias gariepinus) broodstocks. One hundred and twenty male and female broodstocks with an average body weight of 450±0.01g were obtained for the experiment and allocated into 12 experimental fiber tanks at 10 fish per tank (5 males and 5 females). Six diets were formulated (40% crude protein) with different inclusion levels of SWLM; 0, 15, 30, 45, 60, and 90% denoted as the control, SWLM2, SWLM3, SWLM4, SWLM5, and SWLM6 diets, respectively. The fish were fed twice daily at 3% body weight with replicated twice, for 56 days. The results showed that the fish fed with experimental diets significantly improved growth performance, such as weight gain, specific growth rate, and feed conversion ratio. The reproductive indices were significantly higher (p<0.05) in the fish fed with SWLM compared to the control group. The dietary groups treated with SWLM at 30%, 60%, and 90% improved growth performance, intestinal morphology, reproductive indices, and blood profiles of C. gariepinus. The results of the intestinal morphology also showed that SWLM had a significant effect (p<0.05) on the broodstocks. In conclusion, incorporating SWLM in the diets can improve growth performance, blood profiles, intestinal morphology, and reproductive indices in the catfish broodstocks.

The present investigation was carried out to study the age, growth, length-weight relationship, spawning season, length at first sexual maturity, length and age at first capture, mortality, and growth performance of the commercial striped piggy fish, Pomadasys stridens (Forskål, 1775), inhabiting Lake Timsah in Egypt. Fish specimens collected during the period from January 2022 to December 2022 were selected to represent all fish size categories in the catch. The age distribution covered age groups I to V. Total length ranged from 8 to 17.8 cm, while total weight varied from 10.57 to 87.65 g. There was no significant difference between the length–weight relation (LWR) parameters of sexes and pooled data. The overall LWR was found to be W=0.0112×L3.0496. It was found that both males and females matured at a total length of about 12.3cm for males and 12.7 cm for females. The natural spawning period for P. stridens in Lake Timsah is at the end of spring and early summer, from May to July. The von Bertalanffy growth parameters were not significantly different between males and females. The model parameters for both sexes were:  L∞=21.01 cm, K= 0. 245, and t0= -1.5475. The annual rates of total, natural and fishing mortality for male and female P. stridens were calculated as 2.0405 Yr–1, 0.6367 Yr–1, 1.4038 Yr–1 and 2.0151Yr–1, 0.7035 Yr–1, 1.3116 Yr–1 , respectively. The current exploitation rate 'E' was estimated at 0.69 and 0.65 for males and females.

This study investigates the expression of miR-462 in rainbow trout (Oncorhynchus mykiss) during viral hemorrhagic septicemia (VHS) infection to understand its role in disease pathogenesis and immune defense. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression at the post-transcriptional level. VHS is a highly contagious and economically significant viral disease affecting farmed rainbow trout. In this study, 300 rainbow trout were divided into three groups: a negative control group (uninfected), a positive control group (infected without intervention), and an experimental group (infected via intraperitoneal injection with VHS virus). Brain tissue samples were collected over 14 days, and miR-462 expression levels were quantified using molecular techniques. The results showed a significant upregulation of miR-462 in the experimental group, with a 3.5-fold increase compared to controls (p<0.05), indicating its involvement in the immune response to VHS infection. These findings suggest that miR-462 plays a role in the host's response to viral infection. The study highlights the need for further investigation into the specific pathways regulated by miR-462 and its potential as a biomarker for VHS. Limitations include sample size variability, and future studies should explore the functional implications of miR-462 upregulation and its utility in disease management strategies.

Macrobenthos are a key ecosystem indicator and are sensitive to changes in sediments. This study evaluated the ecological status of the Musa estuary located in the northwestern part of the Persian Gulf (Iran) by analyzing macrobenthic community structure and applying biotic indices. The sediment and water samples were collected from six creeks during the summer and winter of 2024 using a Peterson grab and Nansen bottle, respectively. The sediment grain size, total organic matter (TOM), and macrobenthic composition were analyzed. Concurrently, bottom-water physicochemical parameters, including salinity, temperature, pH, and dissolved oxygen concentrations, were measured to assess their potential influence on benthic habitat characteristics. The ecological indices, including AZTI's Marine Biotic Index (AMBI), Benthic Opportunistic Polychaetes Amphipods Index (BOPA), Shannon, Margalef, Pielou, and Simpson, were calculated to evaluate ecological quality. Seventy taxa from seven phyla were identified, with Annelida dominating (69.62%), notably Melinna sp. and Capitella sp. Jafari Creek exhibited the highest macrobenthic density in summer, while Odeleh Creek peaked in winter. Jafari Creek also showed the highest Shannon and Margalef diversity indices across seasons. AMBI and BOPA indicated predominantly unpolluted to slightly polluted conditions, except Ghazaleh Creek, which displayed moderate to severe pollution in winter. TOM positively correlated with the benthic abundance and diversity. Findings suggest that Musa estuary’s ecological status is influenced by natural dynamics and anthropogenic pressures. The study underscores the importance of integrating multiple indices for robust ecosystem assessment.

In the present study, the population characteristics of Auxis thazard and A. rochei were evaluated by sampling at three fish landing sites in the Oman Sea including Beris, Pozm, and Konarak from March 2020 to March 2023. The biometric analysis was performed on 2400 fish specimens. Growth and mortality indices were calculated, including infinite length (L∞=61 and 45 cm), growth coefficient (K=0.40 and 0.46 (yr-1)), growth performance index (Ф=3.18 and 2.93), natural mortality (M=0.77 and 0.68(yr-1)), fishing mortality (F=0.25 and 0.10 (yr-1)), total mortality (Z=1.02±0.09 and 0.78±0.09 (yr-1)), and exploitation coefficient (E=0.25 and 0.13 (yr-1)), as well as t0 (-0.33 and -0.32 yr-1). Relative production per recruitment, relative biomass per recruitment, and exploitation rate of this species were Y / Rp = 0.04, B/Rp=0.23(yr-1), and U=0.2 and 0.09 (yr-1), respectively. The present study showed that the Frigate tuna (FRT) and Bullet tuna (BLT) had desirable stock conditions, and therefore, specific measures should not be taken to reduce catch and fishing efforts. The ratio of spawning potential based on length (LBSPR) of A. thazard and A. rochei was 0.39 (0.35-0.44) and 0.66 (0.59-0.77), respectively. The present study (ratio of LBSPR index and the value of fishing, total mortality and exploitation coefficient) showed that the Frigate tuna and Bullet tuna stock have not reached overfished status. The insights garnered from this research are poised to aid in the management and enduring exploitation of the fish stocks. The findings of this study can assist in the management and sustainable harvest of these tuna species.

Main chitin protein (MCP) is a crucial component of cyprinid herpesvirus 3 (CyHV-3), also known as koi herpesvirus (KHV), found on the surface of the viral capsid. It plays a vital role in protecting viral DNA and assembling viral particles, contributing to the virus's high infectivity and lethality. This study aims to characterize the MCP-encoded protein of CyHV-3, investigate its subcellular localization, and assess its impact on the expression of immune factors through in vitro experiments. Our findings revealed that the CyHV-3 MCP protein consists of 579 amino acids. Despite analyzing evolutionary trees of homologous proteins from three carp herpesvirus sources, no significant similarities were observed. Subcellular localization experiments indicated that the green fluorescent signal of the pEGFP- MCP protein predominantly diffused within the cytoplasm. Remarkably, overexpression of MCP significantly suppressed the expression of immune factors in Channel Catfish Ovary (CCO) and Epithelioma papulosum cyprinid (EPC) cell lines, highlighting its role as a viral immune escape factor. These results enhance our understanding of the immune function of CyHV-3 MCP and provide a theoretical foundation for developing new vaccines against CyHV-3 infections. These results provide further insights into the immune function of CyHV-3 MCP and provide a theoretical basis for the development of new vaccines against CyHV-3 virus infection.

This paper studies the differential changes in growth performance, physiological and biochemical indicators, and intestinal flora of Largemouth Bass in different growth stages, and explores and explains the reasons for the differences, so that breeders can take effective measures to improve the breeding efficiency in the necessary growth stages, and add a complete fish production file to the local and similar areas. The aquaculture pond was regularly monitored and sampled for about five months, with a total of 153 days and an interval of 30 days. After sampling the fish tissue in the test base, put the sample into a foam box with ice bags, and take it back to the laboratory to measure the changes in growth indicators, liver function indicators, antioxidant indicators, and Digestive enzyme indicators of Largemouth Bass in each group according to the national monitoring standards. In addition, the high-throughput sequencing method was used for the intestinal microorganisms of each group, and 16s rRNA analysis was carried out. During the breeding process of Largemouth Bass, the average range of weight gain rate is 35.33-71.33 (p<0.05), of hepatosmatic index is 1.61-2.71 (p<0.05), of total bilirubin is 1.00-4.12 (p<0.05), of cereal grass Transaminase is 3.24-9.53 (p<0.05), of Alanine transaminase is 10.45-38.80 (p<0.05), of Superoxide dismutase is 2.02-3.14 (p<0.05), of Catalase is 4.36-6.91 (p<0.05), and of Pepsin is 52.92-81.84 (p<0.05). The most obvious is that Largemouth Bass has a rapid growth period from June to July. In August, when parasites are widespread, the antioxidant defense system in the body of the Bass is most vulnerable to damage. In October, when the climate gradually cools, the Bass begins to accumulate fat. In addition, among the intestinal flora, the dominant bacteria indifferent growth stages are mainly Mycoplasma and Cetobacterium, and the difference in intestinal flora in different stages is obvious. With the change in growth months, there are obvious differences in the growth performance, physiology and biochemistry, and intestinal flora of Largemouth Bass in different growth stages. In the necessary stages of the breeding process, measures should be taken to improve the health status of the fish, feed nutrition, and pond water quality, and some microecological reagents can be accurately used to improve breeding efficiency. This experiment provides data support for breeding technology improvement, probiotics screening, disease prevention, and intestinal microecology research of Largemouth Bass during its growth.

The use of microalgae is a new and cost-effective biological method for the desalination of saline and brackish waters. For this purpose, after sampling and preparing BG-11 medium with deep aquifer well water, some physicochemical parameters of water were measured and the possibility of reducing the salinity of deep aquifer well water by Scenedesmus obliquus and Chlorella vulgaris algae with cell densities of 1.25 and 2.5×106 cells/mL was investigated. The results showed that the highest salinity, total dissolved solids value (TDS), Na+, Hardness, Nitrate, Phosphate removal and the highest biological desalination rate were observed in S. obliquus algae with a density of 2.5×106, respectively with 9.6%, 27.14%, 7.34%, 25%, 67.01 %, 97.32% reduction, and 28.5±2.50 % for biological desalination rate which showed a significant difference compared to C. vulgaris algae. The highest Chloride removal was observed in C. vulgaris with a density of 2.5×106 cells/mL from 2840 to 828.33±108.45 mg/L (70.83% reduction). The results of dry biomass and algal cell numbers indicated that the highest values were assigned to low and high densities of C. vulgaris algae, with values of 1.03±0.08 and 0.99±0.04 g/L, and 46.35±4.45 and 43.53±4.86 (×106cells/mL), respectively. According to the results, both algae have the ability to reduce deep aquifer well water salinity. Therefore, considering the impact of higher algae densities on further desalination, it is recommended that higher densities be tested.

Temperature and serum separation time from the clot can substantially influence specific biochemical components in fish blood samples. This study aimed to determine the longest permissible clot-contact duration and the most suitable temperature that exerts the least impact on serum biochemical parameters in rainbow trout (Oncorhynchus mykiss). Blood samples were stored under two temperature conditions, 4°C (refrigeration) and 23±2°C (laboratory ambient), alongside a freshly processed control group for 2, 8, and 24 hours. Following each storage interval, the samples were centrifuged, the serum was separated from the clot, and the following biochemical parameters were measured: total protein, albumin, globulin, glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP). Up to 8 hours, total protein, albumin, and globulin remained stable. After 24 hours, globulin levels increased (particularly at room temperature) relative to the control group, although this change did not reach statistical significance (P>0.05). ALT and AST showed a downward trend from the outset; notably, ALT changes became statistically significant at 8 hours under room-temperature conditions (P<0.05). AST alterations were significant at 2 hours in the room-temperature group and 8 hours in the refrigerated group (P<0.05). Glucose, identified as the most unstable metabolite, exhibited a marked but statistically non-significant decline after 2 hours (P>0.05); however, its decrease became significant after 8 hours at room temperature and after 24 hours at both temperatures (P<0.05). These findings demonstrate that AST and glucose are highly time-sensitive indices and should be measured promptly under minimal thermal stress.

The technical efficiency and the capacity utilization of purse seine fisheries in North Sulawesi, Indonesia, were assessed by employing peak-to-peak and Data Envelopment Analysis (DEA) methods. The method gauged the efficiency of fishing gear utilization by comparing the level of input utilization to the generated output. This study used an approach that focused on both input and output approaches. The findings showed an annual increase of approximately 6.7 in the number of purse seiners' cruises, but this did not translate into an increase in the catch per unit of effort. The purse seine fisheries at Tumumpa Coastal Fishing Port experienced excessive capacity utilization for a long period (from 2006 to 2020). It was essential to reduce fishing activities by an average of 54% from 2010 to 2020 to ensure exploitation at the optimum fishing capacity. We averagely computed the efficiency values for vessels with gross tonnages (GT) of less than 30 and greater than 30, respectively. It is imperative to reduce the fishing effort (number of cruises and fishing days), as these values deviated significantly from the optimal value.