Abu Kawsar Didar

The Meghna River, vital for Bangladesh’s ecosystems and livelihoods, faces threats from urbanization, agriculture, industrialization, pollution, and climate change. This study examines the basin’s spatio-temporal dynamics, focusing on hydro-physico-chemical properties (temperature, pH, dissolved oxygen, salinity) and bio-resources (phytoplankton, zooplankton, and benthic macroinvertebrates). Field surveys, laboratory analyses, and satellite imagery revealed consistent patterns, highlighting the ecosystem’s vulnerability and the urgent need for conservation strategies to sustain ecological balance and livelihoods.

This study investigated diversity, availability, current status, population trend, threats and conservation status of SIS in floodplain-rich haorbasin from September 2017 to April 2018. A total of 140 SIS belonging to 35 families and 89 genera were collected from 43 sampling sites (10 in arats/wholesale fish markets, 16 in retail markets, and 17 in fishing locations). Cypriniformes were the most diverse group. 47%, 29%, 14% and 9% of species were moderately available, commonly available, rarely available and abundantly available, respectively. Fish belonging to Cypriniformes and Siluriformes were under moderately available and rarely available categories. Carnivorous was dominant group (49%). National and global population trends of 44% and 13% recorded fish were declining (Perciformes, Siluriformes and Clupeiformes were dominant), whereas most of the species don't have enough biological informationstatus. Out of the 140 species, 4 belong to `critically endangered`, 18 `endangered` and 14 `vulnerable` at national level, beside the order Osteoglossiformes, Sygnathiformes and Cypriniformes were more threatened. Additionally, Mastacembelus oatesiiand Rita ritawere endangered and Channa orientalisand Barilius dogarsinghiwere vulnerable at the global level. Indiscriminate fishing, poisoning, illegal fishing, siltation, pollution and invasive species posed the greatest threat to fish diversity. Climatechange is hard to predict and drastically changing fish habitats and putting SIS at risk. Eco-friendly modern fishing technology, restoration, and potent conservation measures are urgently needed at multiple scales to conserve the fish fauna.