Monitoring, assessment and management of fish farm environments in Japan

In Japan, coastal fish farming has become a well-established industry. Intensive cultivation of finfish, however, generates large amounts of organic waste and nutrients, resulting in environmental deterioration in and around aquaculture facilities. Such negative effects have become increasingly conspicuous since the commencement of fish farming in the mid 1960s and its subsequent rapid development during the 1970s and 1980s. Various studies have attempted to measure the material fluxes in fish farms, to assess the potential environmental impacts, to determine criteria for the optimization of the location of farms and production levels, and to establish methods for improvement of aquaculture environments. In this review, research conducted during the last five decades in Japan concerning the flux of feed, environmental impacts of fish farming, factors controlling the degree of impacts, the upper limit of production and methods for improvement of environments is reviewed and current concerns for aquaculture environments discussed.