In the past, studies of the mackerel and scad fishery emphasize on the biology aspects, such as reproductive biology of the adult fish, age and growth, distribution and migration. Besides, catch and effort data were also discussed to evaluate the status of the stock. Early life history of larval fish determines the success of recruitment and consequently affects the mackerel and scad resources. However, studies about the abundance and distribution of mackerel and scad larvae as well as it’s relationship with environmental factors in the northeastern waters of Taiwan are scarce. Moreover, previous studies about the fishing grounds environment were mostly depend on satellite information and lack of in situ hydrograhic measurements. Therefore, this study will use the research vessels of Fisheries Research Institute to investigate the abundance distribution of the mackerel and scad larvae associated with environmental factors in northern waters of Taiwan.