Journal of Fisheries

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

Debojit Dutta — 2025-12-15

Pesticides, 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.

Growth and nutrient profile of Tetraselmis chuii under different urea concentrations: implications for sustainable uses

Md. Jahid Hossain — 2025-12-14

Nitrogen is regarded as one of the most important nutrients for algal cells, having a direct impact on the growth and biochemical contents of microalgae. The goal of this research was to compare the growth and proximate components of Tetraselmis chuii cultivated in various urea concentrations as an available source of nitrogen. Results disclosed that T. chuii cultivated in urea at 93.4 mg L^–1 N had higher cell density, biomass, and optical density compared to 11.67 mg L^–1, 23.35 mg L^–1, 46.7 mg L^–1, and 233.5 mg L^–1 N, respectively. Protein content was highly significant for urea at 233.5 mg L^–1 N concentration compared to other concentrations. In contrast, higher carbohydrate content was found at 11.67 mg L^–1 N compared to other concentrations of urea. Thus, the current study found that raising or decreasing urea concentrations had a substantial effect on the growth and proximate composition of indigenous marine T. chuii, and the highest biomass was recorded at 0.0145 g L^–1 (dry biomass) from 93.4 mg L^–1 N. These findings have implications for the cultivation of microalgae for various applications, including biofuel production, wastewater treatment, mariculture developments, and a sustainable blue economy in Bangladesh.

Comparison between Indian spinach production in aquaponics utilizing fish wastewater and hydroponics biogas slurry solution

Bably Akter — 2025-12-07

The 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.

First record of the toxic shadow goby Yongeichthys nebulosus (Gobiidae: Gobiinae) from West Bengal, eastern India

Priyankar Chakraborty — 2025-12-03

Herein, the first specimen-based record of Yongeichthys nebulosus (Forsskål, 1775) (Gobiidae) is reported from West Bengal, eastern India. Three individuals were collected from mangrove-associated waters in the Indian Sundarbans, one of which was preserved as a voucher specimen at the Zoological Survey of India. This record represents a north-eastward range extension for the species, which has previously been recorded from other parts of the Indian coast, including the neighbouring state of Odisha. Morphological and meristic features of the voucher specimen are consistent with published diagnoses. The discovery highlights the importance of specimen-based documentation for accurately recording species distributions and emphasises the need for sustained biodiversity monitoring in estuarine habitats.

Effects of dietary protein on growth and nutrient utilization in ornamental koi fish Cyprinus rubrofuscus (Lacepede, 1803)

Waqas Ahmad — 2025-11-20

Ornamental 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.