Japanese jack mackerel is distributed along the Pacific coast of Japan south of Tokyo, in the waters of the Republic of Korea, Democratic People's Republic of Korea and China in the Yellow and Bohai Seas, and south along the coasts of China and Taiwan to Vietnam ((IUCN 2017; Froese and Pauly 2019). Japanese jack mackerel is a transboundary species but since its habitat is generally on the continental shelf it is not likely to be a straddling species. Genetic studies are limited but one which involved testing samples from the east and west coasts of Japan as well as from near Hainan Island (China) found a high level of gene flow between the locations (Zhao et al. 2015). Japan conducts separate annual assessments for the Japanese Pacific coast and Tsushima current fishery units. Jack mackerel catches are primarily taken by purse seines (60%) and set nets (30%) in both fishery units (JFA 2019)(JFA 2019).