My paper examines the historical development of Japanese salmon fisheries in the northern sea (hokuyō) during the interwar years. I focus on fisheries oceanographers and their production of scientific knowledge about the northern sea and salmon’s habits. Historians have pointed out many factors for the rise and prosperity of prewar Japan’s salmon fisheries, such as abundant capital, technological innovation, rational management strategies, cheap labor forces, gunboat diplomacy, armed interventions, and ethnocentric beliefs. However, the earlier scholarship has overlooked the importance of scientific knowledge in prewar Japan’s salmon fisheries. I argue that fisheries oceanographic knowledge was crucial for maintaining prewar Japan’s vibrant salmon fisheries.
Contrary to the earlier scholarship, my paper stresses that the invention of factory ship was shifting the engine of Japanese salmon fisheries from “passive” fisheries in Russian coastal waters to “active” fisheries on the high seas, including Alaskan waters, in the early 1930s. In this process, fisheries oceanographers’ work of making the ocean and salmon’s habits scientifically legible became essential for fishermen. This was because access to salmon growingly depended on to what extent fishermen could know salmon’s migration routes and locate salmon fishing grounds on the high seas in a forecasting way. To scientifically understand salmon’s migration patterns, the fisheries oceanographers surveyed oceanic conditions in the northern sea and conducted tagging experiments even in cooperation with the Soviet Union. This paper offers a corrective to a dominant narrative that overemphasizes confrontation and rivalry between Japan and the Soviet Union over fisheries in the northern sea.