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Tilapia lake virus (TiLV) is an emerging pathogen in aquaculture, reportedly affecting farmed tilapia in 16 countries across multiple continents. Following an early warning in 2017 that TiLV might be widespread, we executed a surveillance programme on tilapia grow-out farms and hatcheries from 10 districts of Bangladesh in 2017 and 2019. Among farms experiencing unusual mortality, eight out of 11 farms tested positive for TiLV in 2017, and two out of seven tested positive in 2019. Investigation of asymptomatic broodstock collected from 16 tilapia hatcheries revealed that six hatcheries tested positive for TiLV. Representative samples subjected to histopathology confirmed pathognomonic lesions of syncytial hepatitis. We recovered three complete genomes of TiLV from infected fish, one from 2017 and two from 2019. Phylogenetic analyses based on both the concatenated coding sequences of 10 segments and only segment 1 consistently revealed that Bangladeshi TiLV isolates formed a unique cluster within Thai clade, suggesting a close genetic relation. In summary, this study revealed the circulation of TiLV in 10 farms and six hatcheries located in eight districts of Bangladesh. We recommend continuing TiLV-targeted Tilapia, which comprises more than 100 species, is the second-most important group of farmed fish worldwide, after carp, and is considered to be among the most significant fish species to meet the rising global demand for protein, vitamin and mineral sources (Amal et al., 2018; Ng & Romano, 2013). Tilapia is farmed in over 135 countries, with global production estimated at 6.5 million metric tons (MMT) (FAO, 2017a). In 2015, the top four producers were China (1.78 MMT), Indonesia (1.11 MMT), Egypt (0.88 MMT) and Bangladesh (0.32 MMT) (FAO, 2017a). Overall, Bangladesh ranks fifth in the world in aquaculture production (FAO, 2017a) and has a total annual fisheries production of 41.34 MMT, of which aquaculture contributes 56.44% (DOF, 2018). The country earns a significant amount of foreign exchange through exporting fish, shrimps and other aquatic animal products from the fisheries sector. In 2017-2018, Bangladesh earned USD 513 million by exporting nearly 68,940 t of fish and fishery products (DOF, 2018). For the last 10 years, the annual growth of the aquaculture sector averaged 5.43% (DOF, 2018). Moreover, tilapia makes up 10.62% of total production and ranks second in the country, after channel catfish (DoF, 2018). Shortly after the first report of a novel disease among tilapia in Ecuador (Ferguson et al., 2014), tilapia lake virus (TiLV) was discovered as a newly emerging virus that caused mass die-offs in tilapia in Israel (Eyngor et al., 2014). Molecular analyses indicated that the same virus, TiLV, was the causative agent of these unusual mortality events in

Culture of shrimp, mainly Penaeus monodon, makes an important contribution to Bangladesh's aquaculture industry. Shrimp hatcheries are the foundation on which the shrimp industry is built. Hatchery performance and management therefore has extremely important implications for the long‐term viability of the entire shrimp sector, especially given its vulnerability to diseases such as white spot syndrome virus (WSSV). This article provides a review of the history of shrimp hatchery development in Bangladesh and an overview of the current status of the shrimp hatchery sector and the challenges it faces. This article also provides a unique historical analysis of shrimp broodstock performance and rates of WSSV infection using data collected from hatcheries between 2007 and 2013. This reveals sharp declines in broodstock quality and performance over time, and high rates of WSSV infection, with potential major implications for the future sustainability of the sector.