Pesticides used in agriculture that wash off have a detrimental effect on freshwater fish in Bangladesh. The purpose of this research is to assess the effects of the organophosphate insecticide Malathion 57 EC on the silver barb (Barbonymus gonionotus). The effects of Malathion 57 EC at dosages of 0.001 and 0.005 ppm, respectively, were assessed using a histological bio-assay of the gill, liver, kidney, and RBC count of B. gonionotus. For B. gonionotus, the LC₅₀ value of Malathion 57 EC was estimated to be 0.08 ppm. The notable alterations included gill clubbing, missing gill lamellae, hyperplasia, nuclear hypertrophy, vacuolation, glomerular enlargement, increasing the width of renal tubules, bleeding, necrosis, and pyknosis were found in the histological analysis. Large lymphocytes, dead cells, tear-shaped cells, a fusion of cells, binucleated cells, ghost cells, senile cells, and irregular cell shapes were among the abnormalities detected in peripheral nuclear erythrocytes. In B. gonionotus, the RBC count was considerably lower (P<0.01) at lower pesticide doses compared to higher ones. The outcome of the study shows that the organophosphorus pesticide has a negative impact on the histology and haematology of various organs in B. gonionotus. Res. Agric. Livest. Fish. Vol. 10, No. 2, August 2023: 207-218

The study was carried out to evaluate the existing fish biodiversity and the socioeconomic state of fishermen in the Charai, Bara beel, and Damas beel regions of the northwestern section of Bangladesh. A field survey was conducted in around 15 locations in the Gomostapur Upazila of Chapainawabganj district. A total of 44 different species of fish have been identified, including 16 common, 17 endangered, and 11 extinct. Five types of fishing gear were available, including a fish net, a fish trap, a hook, Fish Aggregation Devices (FAD), and wounding gear/spears. Illegal and overfishing with illegal fishing gear were identified as important issues in the research areas. Fishermen employed two types of boats: Chandni boats and Dinghi boats. Only 53.3% of the fisherman utilized their own boat, while the rest had no fishing vessels, which was a concerning issue in these areas. Though fishermen employed a variety of marketing strategies, the two-step marketing channel was adopted by half of them. Among the various types of issues confronting the fishermen, the most common was the injustice perpetrated by the local extortionist. The majority of the fishermen had medium fishing experience and a primary level of schooling. Most fishermen earned between 71,000 and 1,00000 taka per year.

Pesticides have become an integral part of agricultural crop production for growing more food. However, the excessive use of pesticides ultimately reaches the aquatic ecosystems and demonstrates pernicious impacts on non‐target aquatic organisms, including fish. Hence, the current study aimed at unravelling the chronic toxicity of an organophosphate insecticide, chlorpyrifos (CPF), on a battery of blood biomarkers, somatic indices and histopathological aberrations of liver and kidney in banded gourami ( Trichogaster fasciata ). Fish were subjected to different sub‐lethal concentrations (0, 15, 50, 150 and 500 µg/L) of CPF for 75 days, and sampling was done at each 15‐day interval. Results indicated a significant rise ( p < 0.05) in glucose, white blood cell levels, mean corpuscular volume and mean corpuscular haemoglobin, and a subsequent decrease in haemoglobin, red blood cell count and packed cell volume. Hepatosomatic index exhibited an increasing pattern, whereas the kidney somatic index followed the opposite trend. Vacuolation, fatty degeneration, dilation of sinusoids and haemorrhage were evident in the liver, whereas kidney histopathology revealed occlusion of the tubular lumen, widened intertubular space, vacuolation, melanomacrophage centre and haemorrhage. Overall, chronic CPF exposure exerted concentration‐ and time‐dependent alterations resulting in anaemia, hepatotoxicity and nephrotoxicity in banded gourami. However, more in‐depth studies are required to understand the changes in fish at the molecular level, such as oxidative stress, gene expression, metabolomic profiling and so forth. The study encourages research for pesticide alternatives and interdisciplinary actions to conserve the aquatic environment as well as the aquatic biota.