Systèmes Ingénieux du Patrimoine Agricole Mondial (SIPAM)

Biwa lake to land integrated system, Japan

GIAHS since 2022


Detailed Information



Global importance

The Biwa lake to land integrated system, which have developed along with paddy rice farming, play a central role in the “Lake Biwa System for Freshwater Fisheries and Agriculture.” The system is centered on traditional eri fishing dating back over 1,000 years that has been passed down across generations by the local people. The Lake Biwa region has traditionally strived to use freshwater resources sustainably, and it currently supplies vital drinking water to 14.5 million people living downstream.

The local people have nurtured rich biocultural diversity through historical interaction between an ecosystem embracing fish and a culture founded on agriculture. They have passed down to modern times traditional resource-friendly fishing methods, social structures for resource conservation that have continued from the medieval period, paddy agriculture practices that provide safe spawning areas for lake fish, and food culture.

Today Lake Biwa is still home to sixteen endemic fish species and the place where a rich social and culinary culture was born to ensure the sustainability of natural resources and food availability. Through centuries, lake fishes and human have become dependent the one from the other.

Food and livelihood security

Around Lake Biwa, fisheries, particularly traditional eri fishing that provides animal proteins important for the local people, have been passed down through small-scale, mostly family-operated fisheries to present times, supporting the livelihoods of fishermen. Furthermore, as diets diversified with economic globalization, the local people have sought to secure food and livelihoods for future generation by passing down the food culture, collaborating with other sectors, and fostering successors.

The majority of fisheries operations are small-scale and family-based and do not target a single fish species. Local fisheries have been sustained as a livelihood by fishing for different species depending on the season, simultaneously practicing agriculture to achieve self-sufficiency in food, and sharing the work on the fishing boat between husband and wife.

In the area around Lake Biwa and its vicinity, people have been engaged in agriculture that is friendly to the water and ecosystems that support the lake fish, contributing to the continuation of the system while supplying safe and reliable agricultural products, notably rice. Lake Biwa activities also include selling cooked food products such as fish tempura and tsukudani that are sold directly to consumers at morning markets. Food processing and sales offer opportunities particularly for women from fishing villages who play a leading role in the community.


Twenty-five species, or approximately half of the 47 native species, are fisheries target species, including the round crucian carp, Honmoroko, and Biwa salmon, which are endemic to Lake Biwa. There is no other area in Japan where such a large number of freshwater fish species are fished for, making Lake Biwa the body of water with the highest diversity of freshwater fisheries target species.

The diversity of agricultural products is characterized by varieties of rice and traditional vegetables, mainly kabu radishes. The majority of farmland practicing environment-oriented agriculture taking into consideration the water quality and ecology of Lake Biwa are rice paddies that cultivate multiple rice varieties such as Koshihikari, Akinouta, and Kinuhikari, from the viewpoint of dispersing the harvesting work across the busy harvest season.

The local practice of using the reeds growing along the shoreline in daily lives has helped to conserve the water quality and the ecosystems. Since the 19th century, the local people have also conserved the water source forests as a measure to prevent floods. This has contributed to stabilizing the water volume in the rivers, thus conserving the spawning grounds of the lake fish that lay their eggs upstream. Mainly birds sit above the lake fish in the food chain and feed on insects, crayfish, frogs, and fish in the rice paddy. Many water birds inhabit the lakeshores, which become a feeding place and resting spot for 140,000 water birds, such as the tundra swan (Cygnus columbianus), particularly in wintertime.

Local and traditional knowledge systems

In Lake Biwa many fishes migrate to different areas of the lake, seasonally or in accordance with their stage of growth including the rice paddy fields. Thus, fishing methods require a strategic setting fishing gear at points where fish are likely to pass, a deep knowledge of fish species and behaviors but also the lake’s topography and influences from natural elements.

One of the most well-known traditional fishing methods is eri fishing that have developed through close interaction with paddy agriculture. Since paddy fields were first developed close to the lake, lake fish species, such as the round crucian carp have come to the paddies through water channels to spawn. Therefore, paddy fields not only bear the function of growing staple rice, but also constitute a part of the lake fish habitat, thus contributing to conserving fishery resources.

Eri fishing is a passive fishing method that involves waiting for fish to wander into a chamber in the back of the eri called the tsubo (pound), created by stretching across a su (mat originally made of reed) or a net, and has the following characteristics:

・Fish that are guided to the tsubo can continue to survive there and trace back their path to exit through the entrance.

・Small and immature fish can be excluded from the catch by setting mats and nets that are more coarsely woven.

・Once installed, eri enable the catching of the required amount fish of a target size through limited operations called tsubokaki that can be performed in between agricultural work.

Lastly, a precious knowledge regarding fish conservation has been developed by the fishermen from Lake Biwa. Indeed, the preserved food is called narezushi is a traditional way of conserving lake fish through lactic fermentation processes with rice.

Culture, value systems and social organizations

Historically, fishermen organization were created before Edo period in order to avoid competition and ensure the sustainable use of Lake Biwa resources. Nowadays fishermen organizations still exist and have led the implementation of restrictions on fishing methods and techniques and establishment of no-take periods and zones with regard to the spawning season. Through collaboration with government and research institutions, fishermen organizations have formulated more effective rules, and by enforcing them, they have succeeded in increasing catches of important endemic species, such as round crucian carp and Honmoroko.

The Biwa lake to land integrated system has historically nurtured a diverse food culture centered on lake fish. Narezushi, a preserved food made by pickling various local lake fish in rice to promote lactic fermentation, is emblematic of the co-evolution of culture and biodiversity. It is served on special occasions as a delicacy to guests and as an offering to the gods at festival held by villages, and has also cultivated human ties, or the social solidarity essential to carry on their livelihoods, such as fishing and farming. Several rituals and ceremony are associated to Narezushi and the identity of local communities.

Landscape and lakescape features

The landscape and lakescape of the system have evolved over many years through interaction between humans and nature, achieving sustainable resource use and conservation. Embracing the rice paddies developed along the lakeshores and the eri set up to catch the lake fish that use the paddies, they were formed gradually through deep interaction with nature, including fish.

Lake Biwa landscape has been largely shaped by the interaction with humans through the development of rice paddy fields but not only. Indeed, another feature of the Lake Biwa System is the use and management of non-crop plants, such as the yoshi reeds on the lakeshores. The reed beds of help conserving the water quality and ecosystems around the lake; and these functions are maintained through regular cutting.