Spatial differences in kombu aquaculture in Minamikayabe, Hakodate City, Hokkaido

Abstract

This study aims to clarify how and why two different techniques of kombu (edible kelp) aquaculture were introduced in Minamikayabe, Hakodate city, at its geographical conditions. Because of the loss of territory in Japan after the Second World War, kombu processors requested for the redevelopment of domestic production centers and began to import kombu from China, Korea, and Russia in the 1960s. Minamikayabe, a well-known production center of natural kombu, faced some difficulties such as the instability of "natural" kombu resources. Consequently, fishermen in this area took up kombu aquaculture, an alternative to the traditional natural kombu production. In 1966, the Kakkumi Fisheries Cooperative began focusing on intensive kombu aquaculture as a part of the pilot program of the Hokkaido Development Bureau. This project successfully implemented intensive kombu aquaculture in this region. An additional benefit of this project was that cultured kombu takes one year to mature, while natural kombu takes two. Subsequently, kombu aquaculture spreaded in other fisheries cooperatives, and Minamikayabe became the largest producer of kombu in Japan. In addition to intensively cultured kombu, the biennial cultured kombu, which can be harvested only after two years, is cultivated in this region. Among the six fishing districts in Minamikayabe, the choice of two techniques of kombu aquaculture differed in Osatsube and Ofune. This choice was partly influenced by hamakakusa, a traditional practice followed in kombu trading, in which the prices of kombu are ranked according to differences in the quality of kombu by district, and which is applied to both natural and biennial cultured kombu. For example, in Osatsube, which has a higher rank under hamakakusa, a certain amount of biennial cultured kombu is continually cultivated. On the other hand, in Ofune, a district with a lower rank, only intensive culture is practiced, because intensively cultured kombu takes less time to mature compared with natural kombu. Thus, in Ofune, the quality of kombu was commensurate with the effort put into production. However, the prices of intensively cultured kombu are not influenced by hamakakusa. The introduction of kombu aquaculture in Minamikayabe enabled fishermen to select either of the two techniques of kombu aquaculture while considering hamakakusa and thereby decreased regional economic disparities.