Increase in the Value of Output by Coho Salmon Aquaculture Management Entities in Miyagi Prefecture: Focusing on Production and Shipment Activities

Abstract

In Japanese marine fish aquaculture, it is thought that the remaining small-scale management entities are sustaining their operations by increasing the value of output. The background of change in the value of output and their production and shipment activities was revealed by fishery economics and fishery geography. However, the relationship between the long-term change in the value of output and activities was not considered sufficiently, as they tended to be treated individually in some studies after the 2000s. Therefore, this study used coho salmon (Oncorhynchus kisutch) aquaculture in Miyagi prefecture, where small-scale management entities are thought to have increased the value of their output since the late 1990s, to reveal how they have increased their value of output, focusing on their production and shipment activities. To understand their activities and management conditions, interviews were conducted with 14 management entities and other actors engaging in coho salmon aquaculture and observing the operations of management entities.

The results of this study can be summarized as follows. In Miyagi prefecture, the fishing grounds for coho salmon aquaculture were already almost saturated, and competition with salmon produced in other countries was intense. In view of this, the selected 14 management entities established production systems enabling an increase in the quantity of salmon seeds released into fish tanks in order to raise the quantity of output. Specifically, they controlled the fish density in tanks, improved feeding efficiency, secured their labor force, introduced new technologies collectively, and relocated fish tanks. These activities were thought to produce positive results, as the quantity of output was estimated to increase. In addition, they improved the quality of salmon and chosen shipment forms. Improved quality of salmon prevented price reductions, but the choice of shipment form did not produce positive results. Therefore, it can be considered that management entities increased the value of output by increasing its quantity through production systems enabling a higher quantity of salmon seeds released into fish tanks, and by improving fish quality to prevent price reductions. Apart from the introduction of extruded pellets, which was confirmed by all management entities, the specific activities were differentiated, depending on the marine area where they were operating, the district or village where they were located, and their plans. The difference in activities is considered to be supported by the following background: since the superiority of any specific activity was not evident, each management entity could engage in production activities based on the conditions it faced. Therefore, it was concluded that in the absence of any superior specific activity, management entities increased the value of output by increasing the quantity of salmon seeds released into fish tanks and improving the quality of fish based on their specific conditions.