Plastic pollution is one of the pressing issues in freshwater ecosystems that may further contribute to coastal pollution. The present study aimed to address the state of macroplastics pollution in the Surma River system, Bangladesh. Six sampling sites were allocated in the river starting from upstream to downstream, water parameters and fin fish assemblage were recorded, and plastic debris was collected from each site. Afterward, macroplastics were categorized and weighed to measure their abundance. Previous data on rainfall, water discharge, and depth were aggregated to study the trend of river depth changes. A survey was conducted to identify the possible sources of plastic pollution in the river and awareness of the pollution. The results showed that Kazir Bazar (Site 4) and Beter Bazar (Site 5), comparatively contained poor water quality, diverse macroplastics categories, and higher macroplastics abundance. The water pollution index (WPI) also ranked the above sites as extremely polluted. Similarly, biodiversity indices revealed lower diversity at Site 4 and Site 5. The river depth analysis revealed that there was no remarkable tendency to change the depth. To conclude, the Surma River system is being polluted due to inadvertent plastic dumping. Contemporary awareness is highly required, and proper policies should be implemented to minimize the detrimental effects of macroplastics.

Determining the most appropriate stocking density for a specific fish species in an ambient condition is essential for successful cage aquaculture in terms of profitability which is mainly governed by growth. The current study was conducted to ascertain which stocking density gives the best result of widely cultured species in cage aquaculture, pangas (Pangasianodon hypophthalmus), at swamp forest environment of Ratargul Freshwater Swamp Forest, Bangladesh in terms of growth, production and economic return. Fish were reared for 93 days at three stocking densities, namely 30, 40 and 50 fish/m³ which were denoted as FSD30, FSD40 and FSD50, respectively, containing three replications of each. Growth and yield comparisons indicated that the stocking density of fish had significant (p < 0.05) effects on growth rate and productivity. Fish cultivated at the maximum density (FSD50) had lower mean weights than fish reared at lower densities. The significantly highest mean weights (376.58 ± 14.65 g) and benefit–cost ratio (BCR) (1.617 ± 0.035) obtained from FSD30 show the suitability of this density in terms of fish growth and profitability of pangas in swamp forest environment.

Heavy metal contamination in Bangladesh has become widespread due to both industrialisation and natural geological processes, posing risks to public health and agriculture. This study aimed to assess the degree of heavy metal pollution in agricultural land of Khulna in Bangladesh, specifically comparing areas near a dumping site with the site further away. Soil samples were analysed for five heavy metals: zinc (Zn), copper (Cu), lead (Pb), cadmium (Cd), and iron (Fe), using indices like contamination factor (CF), pollution load index (PLI), geo-accumulation index (I_geo), and potential ecological risk index (PERI). We observed a significant variation (p < 0.05) in heavy metal concentrations between two sites. Pearson correlations indicated significant relationships among most metals in the near dumping site, suggesting that their concentrations tend to increase. The PLI showed lower pollution (PLI < 1) at the away site compared to the nearby. The CF values indicated moderate level of contamination (1 ≤ CF < 3) at the away site, while considerable contamination (3 ≤ CF < 6) was recorded at the near dumping site. The PERI were higher (95 ≤ PERI < 190) for near dumping site compared to the site away (PERI < 95), indicating a higher ecological risk at near dumping site. I_geo revealed moderate to strong pollution levels for Pb and Cd near the dumping site, whereas away site were unpolluted to moderately polluted. Overall, the findings highlighted cropland near dumping site experiences significantly higher heavy metal pollution than away site, underscoring the need for sustainable remediation and continuous monitoring to protect the environment and public health.

In recent years, the aquaculture sector in Bangladesh has experienced significant technological advancements, notably the adoption of smartphone applications. This empirical study evaluates the current status of smartphone apps available in the aquaculture industry of the country using data obtained from the internet and field surveys. The study identified 41 smartphone apps currently used in the sector, where 58.53 % are related to pond-based aquaculture, 14.63 % are designed for biofloc system, 4.87 % pertain to cage aquaculture and 4.87 % marketing-aided corporate-related apps, 9.75 % focus on disease and treatment-related, and 7.31 % fall into miscellaneous categories. The “Poultry Animals and Aqua Index (PAAI)" app, which addresses aquaculture pharmaceutical inputs and fish disease treatment guidelines, emerged as the most downloaded app in this domain. Pearson correlation analysis indicated that app size or user ratings did not influence app downloads. The study also found that approximately 57.66 % of fish farmers are aware of these smartphone apps. Private fisheries professionals were the main driving forces behind the use of these apps, accounting for 52 % of the information spread. Despite mixed levels of satisfaction among farmers, about 25 % expressed a positive experience. Most of the farmers (57.66 %) acknowledged the awareness and beneficial impacts of using these apps in aquaculture. This study enhances the understanding of smartphone apps usage in Bangladesh to promote the aquaculture industry, highlighting its potential to promote industry growth, alleviate poverty, and contribute to economic development.