Present Scenario of Ocean Warming (OW) and Ocean Acidification (OA) in the Coastal and Marine Waters of the Bay of Bengal, Bangladesh and Implications of OW and OA on Fisheries and Seafood of Bangladesh: A First Regional Review Study

Bangladesh is one of the most vulnerable countries in the world to climate change. However, data relevant to ocean warming (OW) and ocean acidification (OA) are not readily available. This is the first study to review the available data relating to OW and OA covering the three parts (eastern, central and western parts) of the coastal marine waters (CMWs) of the Bay of Bengal (BoB), Bangladesh. The review compared the data collected from the three parts of the BoB, Bangladesh with the data and information of previous research carried out within the Indian subcontinent of the BoB (2000-2023). The present research provides an overview of water quality data relevant to OW and OA and the correlation among different water quality parameters. Our research found that the sea surface temperature is increasing and pH levels are decreasing in the BoB, Bangladesh. The current pH in BoB, Bangladesh is still alkaline, with an overall mean pH of 7.58 compared with the global ocean pH of 8.1. DO (overall mean: 6.09 mg/L), Omega arg (overall mean: 2.27) and Omega cal (overall mean: 3.59) levels were found to be within the safe thresholds for marine biota (fish, crustaceans, mussels, oysters, corals and echinoderms). Conversely, nitrate levels (mean: 2.29 mg/L) were found to be high, the concentration of which may enhance nitrogen pollution, algal blooms and hypoxia in the BoB, Bangladesh. The implications of OW and OA on Bangladesh's fisheries and seafood have been briefly discussed.