Grey mullet possess highly economic value in the coastal fisheries and aquaculture in Taiwan. So-called Wu-Jin in Chinese represents the valuable status of grey mullet like gold in Taiwan. According to the annual reports of fisheries during the period 2000- 2010, the area of the grey mullet culture in Taiwan is about 500-1300 more hectares. The annual production volume is about 1500-2700 tons for the recent 20 years. However, the capture volume of the wild grey mullet have been reduced to few hundreds to 1500 tons because the global climate changed and the neighbor country intercepted. After 2016, the annual production volume of the grey mullet roe is about 50-70 tons whose value is approximately 100- 140 million NTD. The grey mullet culture district in Chubei City is located in the Ba La Ku reclaimed land where has good quality of water resource. The grey mullet roes produced here are the best quality in Taiwan since there are fully sunshine and local winds. Our institute has been successful to make the artificial propagation of the grey mullet in 1970s. The grey mullet farmers still used to take the wild grey mullet larvae for culture because of the cost and affordable supply of the wild larvae. The time of grey mullet culture takes 3 years to harvest the roes. Therefore, to choose the suitable grey mullet larvae lineage for culture could reduce the economic loss due to the growth failure of the roes. This project is aimed at the examination of the correlation between the grey mullet lineages and their gonadal somatic index(GSI). It could provide the farmers practical information when they begin to culture the grey mullet larvae. In addition, it would increase the farmers’ incomes and reduce the cost of risks among various mullet larvae lineages. This year we plan to establish the Recombinase Polymerase Amplification (RPA)& lateral flow (LF) detection technology for the identification of the Taiwanese grey mullet three lineages in order to fit the demands of the mullet farms.