Harmful algal blooms in the coastal waters of Bangladesh: an overview

Harmful algal blooms (HABs) constitute a global problem, affecting aquatic ecosystems, human health, fisheries and local economies. The Bay of Bengal, along the Bangladesh coast, is exceedingly suffering from pollution or anthropogenic nutrification that influences frequently occurring HAB species. The progression of climate change and eutrophication invigorate HAB trends and responses that in turn affect the respective coastal livelihood and economic growth. Tripos spp., Dinophysis spp., Protoperidinium spp., Chaetoceros spp., and Pseudo-nitzschia spp. are the common bloom-forming HAB species in the coastal waters of Bangladesh. Despite having huge potentiality for regional and global perspectives, the coastal region of Bangladesh remains relatively unexplored compared to other regions in the context of HABs and their pernicious effects. As a result, harmful algal blooms and the accumulation of algal toxins may interrupt fisheries, aquaculture, aquatic ecosystems and public health in the country. Therefore, proper research on the biology and ecology of harmful algae, biotoxins and their relationship with environmental factors need to be adequately understood to minimize their adverse effects on the noted marine resources of the Bay. This review focused on an overview of the HAB related issues – causes of HABs, their occurrences and abundances, associated environmental factors and adverse effects in the coastal zone of Bangladesh.