Potential opportunities of Blue economy of Bangladesh The coastal areas and the Bay of Bengal are the heart of blue economy in Bangladesh. Most of theocean economic activities including marine fishing, tourism, research based on the Bay of Bengal consequently change the livelihoods and social status of millions of people inhabiting across the coastal areas. There are several sectors of the blue economy that offer potentials for development to achieve food security and economic development objectives. The potential highlighted sectors for the development of ocean economics in Bangladesh including Fisheries, Marine Biotechnology, marine tourism, marine commerce, shipping and navigations, salt productions, oil and gas mining, bio fueling, and extraction of ocean energy. It has been observed that different economic sectors contributed to the blue economy of Bangladesh with increasing trend.
Potentialities of fisheries and coastal Aquaculture Global food security is very closely related to the sustainable use of marine biodiversity particularly to the exploitation of wild fisheries. One billion people in developing countries depend on seafood for their primary source of protein. The most important areas of the national economy of Bangladesh are the Bay of Bengal and adjacent coastal areas which are enriched with very wide ranges of diverse flora and fauna including fishes, shrimps, mollusks, crabs, mammals, seaweeds etc. The current total fish production is 3.68 million tons, contributing to the 3.69% GDP. The capture fishery contributes to 1.0 million tons (28%), aquaculture 2.2 million tons (56%) and marine fisheries 0.6 million tons (16%) of total fish production (Shamsuzzaman et al., 2020). The single fish species, Tenualosa ilisha, accounts nearly about 42% of total marine catches and 10.5% of the total fish production of the country (Asaduzzaman et al., 2020). In fact, marine aquaculture is mainly based extensively with tiger shrimp (Penaeus monodon) culture (Chowdhury et al., 2019) and at a limited scale with soft cover crab (Scylla serrata) culture and major export is being presently dominated by frozen shrimp and live mud crab and contribution of fin fishes as export items are scanty (Rouf et al., 2016, Sarwer et al., 2017, Bir et al., 2020). In the year 2015, total mollusk fish and fin fish exported from Bangladesh about US$ 582 million (DoF, 2016).
Capture and culture fisheries in Bangladesh Fisheries sectors including culture and capture fisheries greatly contribute the economic development of Bangladesh. Artisanal small-scale fishery contributes 0.51 million tones (86.8%) of the total marine catch (DoF, 2016) including gill nets, set bag net, seine net, push net, hook and line, trammel net etc. are mostly used for fishing within 10-30 meters water depth where trawl fishery contributes only 0.084 million tones which is 14.2% of total marine production (DoF, 2016). Large trawlers are used for mostly penaeid shrimps and finfish fishing within the depth of 40- 100 meters (Hussain et al, 2017, Rahman, 2017). In case of marine capture fisheries, still depending on traditional fishing practices beyond the standing fishing grounds within 200 nm of EEZ (Shamsuzzaman et al., 2020). Another important task is the rehabilitation of hilsa fishery. At present 50-60% of global hilsa catch takes place in the coastal and marine waters of Bangladesh, 20-25% in Myanmar, 15-20% in India and the remaining 5- 10% in other countries (Hossain et al., 2014, Asaduzzaman et al., 2020). Hilsa is a transboundary species of Bay of Bengal and Bangladesh, India and Myanmar might be effective to prevent the harvest of hilsa juveniles (Asaduzzaman et al., 2020). The government of Bangladesh has already taken initiatives to protect the mature brood stock during the banning period and being successful in this issue. Similarly, some regulation measure can be addressed on indiscriminate harvesting of mature mother shrimp, P. monodon by trawling at the depth of 10-40 meters of inshore marine waters and it will certainly conserve the tiger shrimp brood stocks.
Culture of nontraditional fauna There are also many existing opportunities for mariculture of some nontraditional species. These nontraditional species include not only seaweeds but also some other macroalgae, mussels, oysters and other mollusk like edible oysters, Crassostrea sp., Saccostrea sp., pearl oyster, Anadrasp., green mussel, Pernaviridis, clam, Meretrix meretrix, Marcia opima, sea snails etc. Lesson, for adopting innovative technologies, can be learned from the other countries to initiate mariculture of above-mentioned species and also for sea urchin, sea cucumber, etc.
Production of rock and sea salt Bangladesh has huge opportunities of sea salt production because of huge coastal area with the favorable environment. Salt production in Bangladesh has been traditionally practiced mostly onshore areas like Chakaria, Cox's Bazar, Bashkhali, Technaf, etc. In spite of having enormous potentiality, still most of the salt farm remain in small scale just conventionally the farmers lease the landfrom landowners and captive the seawater with a fence (Hossain et al., 2006). There for the production and quality of salt not enough satisfactory level. Here in Bangladesh average crude salt production is about 7000-10,000 kg/ha (Alam, 2014). Moreover, salt industry is tremendously affected by sea level rise, degradation of coastal areas and ocean pollutions thus reduces the rate of salt production. Recently, some advanced countries in Europe and North America are using modern techniques and collecting and refining common salt by mining. If we can introduce these technologies, salt productions will increase and might be a good renewable resource in Bangladesh.