Journal of Fisheries (University of Rajshahi)
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Stock assessment of Crossocheilus diplochilus (Heckel, 1838) in Dal Lake of Kashmir Himalayas
Full text linkThe intricate dynamics governing population parameters stand as pivotal pillars in the realm of fish management and conservation. Accordingly, the various parameters of population dynamics of Crossocheilus diplochilus (Heckel, 1838) from the Dal Lake of Kashmir valley were investigated. The study reported that the fish exhibits a length range of 5.4 to 14.8 cm and a weight range of 1.24 to 17.19 g. The b value was reported to be 2.9 depicting negative allometric growth. The Fulton and relative condition factors were reported to be 0.86 and 0.99 respectively. The growth constant, asymptotic length, age at zero length and growth performance index were reported to be 0.33 year–1, 17.40 cm, –0.62 years and 2.0 respectively. Fishing mortality was found to be higher than the natural mortality. The exploitation ratio was reported to be 0.52 which was found to be lower than the exploitation rate producing maximum yield (0.81). This is suggestive of an underexploited state of fishery of C. diplochilus from this lake
Comparison between Indian spinach production in aquaponics utilizing fish wastewater and hydroponics biogas slurry solution
Full text linkThe experiment compared Indian spinach production in aquaponics utilizing fish wastewater and hydroponics with biogas slurry solution. The aquaponics system involved 60 juvenile tilapias, released into a 750 L tank with an average initial length and weight of 14.41 ± 0.66 cm and 49.81 ± 4.29 g, respectively. The fish were fed commercial pelleted feed twice daily and maintained suitable water quality parameters, including pH, temperature, and DO, within the required range. The hydroponics system used biogas slurry as nutrient media. In each system, 3 plant beds were used, and 4 Indian spinach plants were planted in each bed. Physical parameters of water indicated that the aquaponics system had higher levels of EC, HCO3, CO3, Total-N, potassium, sulphur, and sodium than the hydroponics system. After 90 days, aquaponics had the largest plant weight (82.05 ± 23.31 g), with significantly higher levels of nitrogen, potassium, and sulphur content (by 5.54%, 3.10%, and 0.61% respectively) in leaves was found in aquaponics, while the phosphorus (0.85%) was higher in hydroponics. The yield of Indian spinach was higher in aquaponics (2.88 kg m–2) than in hydroponics (1.52 kg m–2). Length gain of experimental fish in aquaponics was 10.54 ± 1.51 cm, weight gain 112.71 ± 21.75 g, with a percent weight gain of 227.23 ± 42.98, specific growth rate of 1.4 ± 0.16% day–1, which was normal. The study concluded that wastes from tilapia aquaponics are more suitable for Indian spinach cultivation than low-cost biogas slurry hydroponics
Effects of carbon sources on production performance, enzymatic efficiency and biochemical indices of Nile tilapia under biofloc culture system
Full text linkBiofloc technology (BFT) is a sustainable aquaculture system based on the principle of nutrient recycling. This study evaluated the effects of starch, molasses and corn flour as carbon sources on water quality, growth performance, proximate body composition, hematological indices, immune responses and antioxidant status of Nile tilapia in biofloc system. A 12-week trial was conducted with juvenile Nile tilapia (25.3 ± 0.6 g), which were randomly assigned to four treatments. The treatments were BFT with corn flour (BFT+CF), molasses (BFT+M), starch (BFT+S) and a control group. Physicochemical parameters of water were affected by the carbon sources but remained within the optimal range for tilapia culture, with the highest biofloc volume (34.1 mL L–1) observed in BFT+M. Growth performance was significantly increased in BFT+M, which yielded the superior weight gain (125 g), survival rate (99.03%) and the lowest feed conversion ratio (17.1). Proximate analysis revealed the highest crude protein levels in fish reared under BFT+M and BFT+S. Hematological parameters (hematocrit, hemoglobin, WBCs and RBCs) and non-specific immune responses (albumin, globulin, immunoglobulin and lysozyme activity) were significantly improved in BFT+M and BFT+S groups compared to the control. In conclusion, the supplementation of biofloc system with molasses and starch as carbon sources significantly improved growth performance, hematology, immunity and antioxidant capacity of Nile tilapia
Investigation on the cypermethrin-induced genotoxic, biochemical, and antioxidant gene expression modulations in the gill tissue of Pethia conchonius, a resident fish of river Teesta, India
Full text linkPesticides, an integral part of agricultural practices, contaminate aquatic bodies through surface runoff and leaching and threaten non-target organisms like fish. Synthetic pyrethroids, a widely used insecticide group have been shown to have detrimental effects on fish. Pethia conchonius, a non-target fish from river Teesta was used as a model organism to evaluate the detrimental effects of pyrethroid insecticide, cypermethrin on fish. The comet and micronucleus assays revealed cypermethrin-induced severe nuclear DNA damage showing three-fold decrease in % head DNA with a concomitant 70-fold increase in % tail DNA, and up to 21 times increase in MN frequency for SLC III at 96 hr exposure. The SOD, CAT, and GPx assays in gills and their mRNA expression analysis indicated down regulation of these anti-oxidant enzymes in a concentration and time-dependent response, with the lowest decrease being 4.2, 2.2, and 1.8-folds respectively for each of the enzymes at 96 hr of cypermethrin treatment in comparison to the control (p > 0.05). Subsequently, elevated levels of MDA in the gills of cypermethrin-treated P. conchonius further indicated increased oxidative stress and lipid peroxidation. Elevated oxidative stress and ROS levels can cause DNA damage and disrupt normal cell functioning, biochemical pathways, and cell cycle. The results indicated that cypermethrin is highly genotoxic and induces oxidative stress in the fish, supporting its hazardous effect on non-target organisms in aquatic ecosystems
Effects of dietary protein on growth and nutrient utilization in ornamental koi fish Cyprinus rubrofuscus (Lacepede, 1803)
Full text linkOrnamental fish farming is an expanding sector and determining the ideal dietary protein for fish growth is crucial for the success of fish farming in developing countries. In this study, the impact of varying dietary protein (DP) levels (25, 30, 35, 40, 45 and 50%) on the growth and feed conversion ratio (FCR) of koi fish (Cyprinus rubrofuscus) were assessed. The fish fed twice daily for 90 days at a rate of 5% of their body weight and growth parameters and FCR measured every 15 days. Results revealed that the highest weight gain (170.98 g) observed with the 35% DP diet (D-3), while the lowest gain (103.98 g) occurred with the 45% DP diet (D-5). The 35% DP diet also produced the specific growth rate (0.59±0.10), protein efficiency ratio (PER) 2.27±0.27 and feed efficiency percentage (FE%) 60.57±4.40, all of which were significantly higher (p < 0.05) than those from the other diets. The best FCR value of 1.65±0.12 was also found in the 35% DP diet (D-3), which was significantly lower (p < 0.05) than the others. Nutritionally, moisture and ash content was significantly lower (p < 0.05) in D-3 as compared to other diets. Additionally, dietary protein levels had a significant effect (p < 0.05) on final weight, specific growth rate, protein efficiency ratio and protein feed of C. rubrofuscus. These findings offer important insights into the optimal dietary protein level for C. rubrofuscus, which could help improve the commercial success of ornamental fish farming
Assessment of fish consumption behaviour and market forecasts for sustainable fisheries in Manipur, India
Full text linkThis study analysed the socio-economic characteristics, consumption behaviour and expenditure patterns of fish-consuming households in Manipur, India, using data from 450 households across six districts belonging to different social background. Secondary data (2015 – 2025) obtained from government records supported a production-requirement forecast. The regression model demonstrated a moderately strong relationship between the predictors and the dependent variable (R² = 0.588; adjusted R² = 0.581). A paired t-test revealed that monthly expenditure on fish alone ₹5,326.88 (~59.20 $) was much higher than other non-vegetarian foods ₹2,310.44, comprising nearly 70% of the total non-vegetarian expenses. Holt’s exponential smoothing model (R² = 0.813, MAPE = 2.71%) projected that fish demand will exceed supply from 2024 – 2029, indicating a widening gap. The study concludes that fish holds cultural and nutritional importance in Manipur and calls for enhanced aquaculture, better market infrastructure, and improved consumer awareness for sustainable fish supply and food security
Antimicrobial resistance and phage sensitivity of Chryseobacterium sp. isolated from diseased rainbow trout (Oncorhynchus mykiss)
Full text linkThis study aimed to isolate and characterize bacteriophages infecting Chryseobacterium sp., an opportunistic pathogen responsible for considerable mortality in rainbow trout (Oncorhynchus mykiss Walbaum, 1792) aquaculture. Chryseobacterium isolates were recovered from diseased trout collected from aquaculture facilities in Mersin and Van (Türkiye) using Anacker–Ordal medium. Identification was performed through API 20E/20ZYM biochemical profiling and 16S rRNA gene sequencing. Antibiotic susceptibility was evaluated by the Kirby–Bauer disk diffusion method following CLSI and EUCAST guidelines. Phages were isolated from water samples via 0.22 μm filtration and purified using the double-layer agar method. Antimicrobial susceptibility testing revealed that Chryseobacterium isolates were sensitive to enrofloxacin, oxolinic acid, and ciprofloxacin, but exhibited pronounced resistance to most β-lactam and aminoglycoside antibiotics. A total of 19 lytic phages (CV1 – CV19) were successfully isolated. They displayed latent periods between 2.5 and 7.5 h and burst sizes ranging from 20 to 235 PFU per cell. The highest burst size and shortest latent period were recorded for the CV5 phage. Adsorption rate constants showed phage-specific variability, with overall values ranging from 1.05×10⁻⁶ to 2.55×10⁻⁶ mL·min⁻¹. Genome sizes were estimated at 48 – 75 kb. TEM revealed typical tailed morphologies consistent with the order Caudovirales. Host range assays showed strong species specificity, with limited cross-activity against Flavobacterium psychrophilum and Enterococcus faecalis. The findings confirm that these phages possess traits favorable for use as eco-friendly biocontrol agents, offering a promising strategy to mitigate Chryseobacterium-associated infections and reduce antibiotic dependence in trout hatcheries
The role of integrated prawn farming in climate change adaptation in Bangladesh: ecosystem services, economic viability and barriers
Full text linkThe integrated rice-prawn-vegetable culture (RPVC) is an effective farming method that ensures the efficient utilization of water and land. This study aims to evaluate the role of RPVC in climate change adaptation, its ecosystem services, and economic sustainability in Bangladesh. Integrated RPVC provides farmers with ecosystem services, including reducing use of the fertilizers and insecticides and lowering financial instability. The vegetable platform shades prawn ponds naturally, while prawns consume insects in rice fields. After rice plants are harvested, their roots can serve as food for prawns. Majority of the respondents (85%) reported that adopting RPVC increased the overall productivity. Farmers faced a variety of climatic hazards; ranked as: drought (86.3%) > erratic and sudden heavy rainfall (81.5%) > temperature fluctuation (69.6%) > salinity intrusion (67.2%) > storm (28.5%). The ecosystem services provided by RPVC helped farmers to mitigate the adverse impacts of these climate-induced challenges through ecosystem-based adaptation. Integrated RPVC has also enabled farmers to maintain a consistent cash flow throughout the year. By promoting the production of multiple commodities—rice, prawns, and vegetables—the system reduces the risk of financial destitution. Despite benefits, farmers also encountered several challenges in implementing RPVC including water shortage (85.2%), disease (73.5%), theft (60.4%), increased feed costs (70.7%), lack of information (65%), increased labor cost (58.8%), and not getting expected market value of farming products (63.2%). However, if these barriers are addressed, the integrated RPVC system holds significant potential to foster long-term socio-economic growth in the southwest region of Bangladesh
Fish and macrophyte diversity in a tropical river under threat from municipal waste
Full text linkFishes thrive in balanced ecosystems, where threats like invasive fish species and extensive anthropogenic activity can significantly reduce native fish populations. Macrophytes play a crucial role in providing shelter and breeding grounds for small native fish species. This study was conducted to assess the fish and macrophyte diversity, water quality parameters, and potential pollution sources in a tropical river (Virinjipuram (Palar) River, Tamil Nadu) in India between January and March 2025. It also highlights the anthropogenic impacts on fish population. Our results show that 20 species were identified including 18 native and 2 exotic species (Oreochromis niloticus and Oreochromis mossambicus). Cypriniformes was the most dominant order with 12 fish species, followed by Perciformes (3 species), Cichliformes (3 species) and Siluriformes (2 species). IUCN global status of native species revealed 16 species as Least Concern, Parambassis lala as Near Threatened and Devario fraseri as Vulnerable. Five macrophytes were observed, indicating potential interactions between fish populations and macrophytes in influencing habitat dynamics. The presence of invasive species and extensive municipal waste dumping along the riverbank is of major concern. Our present finding suggests that measures have to be taken to mitigate the anthropogenic activities to conserve the native fish fauna
Current status of blood cockle (Tegillarca granosa) aquaculture off Myeik City, Myanmar
Full text linkBlood cockle aquaculture has played a vital role in the local economy around Myeik City, a major fishing hub in southern Myanmar, in recent years. This study aimed to assess the current state of aquaculture grounds and to contribute to the development of sustainable blood cockle farming. To determine the status of sowing aquaculture grounds, the main fishing sites were identified through boat-based surveys and interviews with local fishermen. Environmental characteristics of these areas were estimated using satellite imagery, along with weather and sea condition data. Additionally, shell length and whole weight of blood cockles purchased from a market in Myeik City were measured, and their digestive tube contents were examined. These results revealed that farming grounds were located around coves and creeks on small islands along the east coast of Kadan Island. These areas were characterised by high turbidity, with salinity remaining stable year-round at over 20 PSU. The annual chlorophyll-a concentration, approximately 4 μg L–1, indicated a consistent presence of phytoplankton, which was also confirmed by the digestive content analysis. However, compared to data on blood cockles from other regions reported in related studies, those collected after the rainy season were noticeably lighter in weight, indicating a leaner condition. These findings suggested that alternating the use of offshore and coastal aquaculture grounds according to the rainy and dry seasons may enhance farming efficiency and realise sustainable aquaculture practices