Development and analysis of a geospatial database for maritime spatial planning in Bangladesh.

In this research we collect, prepare and analyze a geospatial database of maritime activities located in the northern Bay of Bengal with the final aim to simulate maritime spatial planning (MSP) - ready information source for future sectoral and multi-sector MSP in Bangladesh. The database is composed of 28 anthropogenic and environmental layers categorized into seven Blue Economy sectors. The database is analyzed with a set of geospatial models aimed at understanding the intensity distribution of human activities at sea and the potential marine use conflicts emerging from the aggregation of human activities. Ecological resources were characterized in terms of marine mammals, lobsters, commercially important and threatened fish species, and pelagic birds and mapped as biodiversity hotspots using geographic cluster analysis. Results show that the most intensely used sea areas are located along the northeastern coast of Bangladesh, as well as in the Swatch of No Ground (SoNG) area, with maximum Marine Use Intensity (MUI) scores ranging from 5 to 8. Offshore waters of Saint Martin's Island have higher MUI scores (≥ 5) as well. The pairwise spatial conflict analysis shows that nature protection sites particularly SoNG Marine Protected Area (MPA), Nijhum Dwip Marine Reserve (MR), and Saint Martin's Island MPA are exposed to the high Marine Use Conflicts (MUC) induced by fishing and shipping activities. Fishing operations generate the highest MUC value (MUC = 30) in SoNG MPA, whereas shipping activities produce the highest MUC value (MUC = 24) in Nijhum Dwip MR. Both of the MPAs exhibit 6 to 12 MUC scores induced by shipping. The proposed database together with the illustrated analytical techniques used in this study and key findings can provide the first understanding of the priorities for Ecosystem Based Management of Bangladesh's marine space and provide valuable insights on the urgency for MSP process in the country. The study concludes with an outlook on the utility of the database for future analysis.

Bioaccumulation and Bioremediation of Heavy Metals in Fishes-A Review.

Heavy metals, the most potent contaminants of the environment, are discharged into the aquatic ecosystems through the effluents of several industries, resulting in serious aquatic pollution. This type of severe heavy metal contamination in aquaculture systems has attracted great attention throughout the world. These toxic heavy metals are transmitted into the food chain through their bioaccumulation in different tissues of aquatic species and have aroused serious public health concerns. Heavy metal toxicity negatively affects the growth, reproduction, and physiology of fish, which is threatening the sustainable development of the aquaculture sector. Recently, several techniques, such as adsorption, physio-biochemical, molecular, and phytoremediation mechanisms have been successfully applied to reduce the toxicants in the environment. Microorganisms, especially several bacterial species, play a key role in this bioremediation process. In this context, the present review summarizes the bioaccumulation of different heavy metals into fishes, their toxic effects, and possible bioremediation techniques to protect the fishes from heavy metal contamination. Additionally, this paper discusses existing strategies to bioremediate heavy metals from aquatic ecosystems and the scope of genetic and molecular approaches for the effective bioremediation of heavy metals.