Abstract
<title>Abstract</title> <p> The Vulnerable Irrawaddy dolphin ( <italic>Orcaella brevirostris</italic> ) faces critical threats in Bangladesh, home to a key population in the Sundarbans ecosystem. This study analyzes spatio-temporal mortality patterns from 29 events (135 deaths) recorded between 2000 and 2024. Using integrated geospatial and statistical methods, we identified significant mortality clustering (Global Moran's Index = 0.782, p < 0.00001), with hotspots at the Kuakata Coast and Sonarchar. Mortality rates accelerated, with mean deaths per event rising from 2.3 (2000-2009) to 6.7 (2020-2024). Bycatch was the primary cause (68% of deaths), followed by vessel strikes (26%), with mortality strongly correlated with proximity to fishing ports (r = -0.62, p = 0.003). A composite risk model prioritized critical zones covering 147 km², which accounted for 68% of mortality. This provides an evidence-based framework for targeted conservation, recommending spatial management, fishing restrictions, and enhanced monitoring to mitigate anthropogenic impacts on this threatened population. </p>