Productivity and coastal fisheries biomass yields of the northeast coastal waters of the Bay of Bengal Large Marine Ecosystem

Abstract

Abstract Myanmar (Burma) is the second largest territory in Southeast Asia with a 2200\u202fkm coastline and continental shelf of 230,000\u202fkm2. The Myanmar exclusive economic zone (EEZ) occupies 80% of the northeast coastal waters of the Bay of Bengal Large Marine Ecosystem (BoBLME); a 300\u202fkm stretch of the Bangladesh coastline completes the area. Four decades ago a combination of extensive mangrove forests, large continental shelf and fertile deposits from the rivers systems discharging into the Bay from two mega deltas (Ganges–Brahmaputra–Meghna and the Ayeyarwady) generated high productivity and valuable coastal fisheries. In terms of productivity, the end of the dry season (April) is the most productive, with 2590\u202f±\u202f1560\u202fmg\u202fC m⁻2 day⁻¹\u202fand high concentrations of chlorophyll a (3.14\u202f±\u202f2.64\u202fµg\u202fL⁻¹). In 2016, the Department of Fisheries (DoF Myanmar) reported marine fishery landings in Myanmar s waters of 2.9 million metric tons (mt), which would have accounted for 47% of the total BoBLME fish catch and 3% of global fisheries coming from 10% of the BoBLME maritime area of 6.2 million km2. Sequential fisheries assessments by Fridtjof Nansen Fisheries Research vessels over four decades have shown that in 2015 a combination of factors has led to reduced yields of valuable fish species by 80% while low value, fast-recruiting fish species have increased. A 2011 Transboundary Diagnostic Analysis (TDA), delivered by the Global Environment Facility (GEF) co-funded FAO implemented BoBLME eight-country project, describes the causes for this dramatic reduction in biomass yields. A Strategic Action Programme (SAP) designed to mitigate the problems was endorsed in 2016 and will be implemented in 2019. The area s coastal fishing fleets are 95% artisanal. There is a combined total of 442 species of fish, prawn, shrimp and lobster in the area. The transboundary hilsa (Tenualosa ilisha) fishery is the most economically important in both Bangladesh and Myanmar. WorldFish and the DoF (Bangladesh and Myanmar) are currently operating hilsa conservation projects in both countries with the International Institute for Environment and Development (IIED) and USAID funded Enhanced Coastal Fisheries in Bangladesh (ECOFISH) projects. A 2018 FAO-WorldFish fisher folk vulnerability and social protection study has demonstrated the precarious nature of coastal fishers.