The agriculture, forestry and fishery in Shiga Prefecture, Japan have coexisted with the lake for more than 1,000 years. It is lake to land integrated system. We call this system “Lake Biwa System”. Lake Biwa System was certified as a Globally Important Agricultural Heritage System in July 2022.
Globally Important Agricultural Heritage Systems (GIAHS) are globally significant sustainable agriculture, forestry and fishery industries which have been developed and shaped for generations while adapting to the society, environment, culture, landscape and biodiversity that they are connected with. These are systems that the United Nations Food and Agriculture Organization (FAO) certifies.
“Lake Biwa System” is centered on traditional inland water fisheries which have developed along with paddy agriculture. It comprises paddy agriculture that provides safe breeding grounds for spawning lake fish. Traditional fishing methods enable the selective catching of only a required amount of lake fish of a certain size. This system has a history of more than 1,000 years that integrates agriculture and fisheries, and it has continued to provide sustainable resource use in freshwater systems located in an area where urbanization has taken its course. For this reason, Lake Biwa is a very important water sources fishing ground for inland water fisheries.
However, in 1977, the first major bloom of freshwater red tide occurred in Lake Biwa. Public campaigns to use soap instead of synthetic phosphorus detergents led to the enactment of the Ordinance Concerning the Prevention of Eutrophication of Lake Biwa in 1979, based on which reduced fertilizer use and measures to treat agricultural wastewater were promoted in the agricultural area surrounding Lake Biwa. Even now, to conserve the water quality and ecosystem of Lake Biwa, many farmers are implementing environmentally friendly agriculture. Lake to land focused environmentally sound agricultural products are produced by reducing the use of synthetic agrochemicals and chemical fertilizers by 50% in addition to applying drainage management to prevent soil runoff. To support this initiative, the Ordinance Concerning the Promotion of Lake to Land-Focused Environmentally Sound Agriculture was enacted in March 2003.
As a result of these initiatives, Outflow loads from agricultural lands flowing into Lake Biwa has decreased and agricultural land has also become rife with various lifeforms.