噴火湾におけるホタテガイ養殖の現状と適正養殖量推定のための諸課題

抄録

Hanging culture of Japanese scallops (Mizuhopecten yessoensis) constitutes the most important fishery in Funka Bay, located in the southeastern part of Hokkaido, Japan. Scallop culture started in the early 1970s and developed into an important industry involving scallop processing and distribution not only as locally important industries, but also as a pillar of the Hokkaido economy. The carrying capacity of scallops cultured in Funka Bay was estimated in 1977-1978 for the first time; after that, however, cultured scallop production continued to increase year by year owing to failure to control on the basis of this estimate. At present, scallop production far exceeds the carrying capacity. The carrying capacity model used to calculate that early estimate was based on the difference between food production and food consumption in the scallop culture area. Controllability of product size and quarity is a marked characteristic of mariculture. I have incorporated the idea into the old 1977-78 model. A new model proposed herein will be useful as educational tools for businesses involved in scallop culture. The huge number of scallops hanging in the coastal area, where their culture areas occupy 19% of the total area of Funka Bay, undoutedly has important ecosystem-level effects in the bay. We need to assess the ecosystem-level effects of the scallop culture and devise a new standard of carrying capacity estimation in order to improve the sustainability of this fishery.