is the largest freshwater

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

in Japan, located entirely within

Shiga Prefecture is a prefecture of Japan located in the Kansai region of Honshu. Shiga Prefecture has a population of 1,412,916 (1 October 2015) and has a geographic area of . Shiga Prefecture borders Fukui Prefecture to the north, Gifu Prefecture to the north ...

(west-central

Honshu , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island se ...

), northeast of the former capital city of

Kyoto Kyoto (; Japanese language, Japanese: , ''Kyōto'' ), officially , is the capital city of Kyoto Prefecture in Japan. Located in the Kansai region on the island of Honshu, Kyoto forms a part of the Keihanshin, Keihanshin metropolitan area along wi ...

. Lake Biwa is an

ancient lake An ancient lake is a lake that has consistently carried water for more than one million years. Many have existed for more than 2.6 million years, the full Quaternary period. Ancient lakes continue to persist due to plate tectonics in an active ...

, over 4 million years old. It is estimated to be the 13th oldest lake in the world. Because of its proximity to

, references to Lake Biwa appear frequently in Japanese literature, particularly in poetry and in historical accounts of battles.

Name

The name ''Biwako'' was established in the

Edo period The or is the period between 1603 and 1867 in the history of Japan, when Japan was under the rule of the Tokugawa shogunate and the country's 300 regional '' daimyo''. Emerging from the chaos of the Sengoku period, the Edo period was characte ...

. There are various theories about the origin of the name ''Biwako'', but it is generally believed to be so named because of the resemblance of its shape to that of a stringed instrument called the '' biwa''. Kōsō, a learned monk of

Enryaku-ji is a Tendai monastery located on Mount Hiei in Ōtsu, overlooking Kyoto. It was first founded in 788 during the early Heian period (794–1185) by Saichō (767–822), also known as Dengyō Daishi, who introduced the Tendai sect of Mahayan ...

in the 14th century, gave a clue to the origin of the name ''Biwako'' in his writing: "The lake is the Pure land of the goddess Benzaiten because she lives on

Chikubu Island is a small island in the northern part of Lake Biwa in Shiga Prefecture, in the Kansai region of Japan. It has been known since ancient times for the beauty of its scenery and for its small Shinto shrine and Buddhist temples. Administrativel ...

and the shape of the lake is similar to that of the ''biwa'', her favorite instrument." The lake was formerly known as the or the . Later the pronunciation ''Awaumi'' changed to the modern ''Ōmi'' as in the name of

Ōmi Province was a province of Japan, which today comprises Shiga Prefecture. It was one of the provinces that made up the Tōsandō circuit. Its nickname is . Under the '' Engishiki'' classification system, Ōmi was ranked as one of the 13 "great countr ...

. The lake is also called in literature.

Area and use

The area of this lake is about 670 km² (258.69 sq mi). Small rivers drain from the surrounding mountains into Lake Biwa, and its main outlet is the

Seta River The , also called the Seta River (瀬田川 ''Seta-gawa'') and the Uji River (宇治川 ''Uji-gawa'') at portions of its route, is the principal river in Osaka Prefecture on Honshu, Japan. The source of the river is Lake Biwa in Shiga Prefec ...

, which later becomes the Uji River, combining with the Katsura and Kizu to become the

Yodo River The , also called the Seta River (瀬田川 ''Seta-gawa'') and the Uji River (宇治川 ''Uji-gawa'') at portions of its route, is the principal river in Osaka Prefecture on Honshu, Japan. The source of the river is Lake Biwa in Shiga Prefectur ...

and flows into the Seto Inland Sea at

Osaka Bay Osaka Bay (大阪湾 ''Ōsaka-wan'' ) is a bay in western Japan. As an eastern part of the Seto Inland Sea, it is separated from the Pacific Ocean by the Kii Channel and from the neighbor western part of the Inland Sea by the Akashi Strait. ...

. It serves as a reservoir for the cities of

and

Ōtsu 270px, Ōtsu City Hall is the capital city of Shiga Prefecture, Japan. , the city had an estimated population of 343,991 in 153458 households and a population density of 740 persons per km². The total area of the city is . Geography Ōtsu is ...

and is a valuable resource for nearby textile industries. It provides drinking water for about 15 million people in the

Kansai region The or the , lies in the southern-central region of Japan's main island Honshū. The region includes the prefectures of Nara, Wakayama, Kyoto, Osaka, Hyōgo and Shiga, often also Mie, sometimes Fukui, Tokushima and Tottori. The metropoli ...

. Lake Biwa is a breeding ground for freshwater fish, including

trout Trout are species of freshwater fish belonging to the genera '' Oncorhynchus'', '' Salmo'' and '' Salvelinus'', all of the subfamily Salmoninae of the family Salmonidae. The word ''trout'' is also used as part of the name of some non-salm ...

, and for the pearl culture industry. The Lake Biwa Canal, built in the late 1890s and later expanded during the Taishō period played a role of great importance in the rekindling of Kyoto's industrial life, after a steep decline following the transfer of the capital to Tokyo. Lake Biwa is home to many popular beaches along the north-western shore, in particular, for example,

Shiga is a prefecture of Japan located in the Kansai region of Honshu. Shiga Prefecture has a population of 1,412,916 (1 October 2015) and has a geographic area of . Shiga Prefecture borders Fukui Prefecture to the north, Gifu Prefecture to the nort ...

Beach and Omi-Maiko. The Mizunomori Water Botanical Garden and The

Lake Biwa Museum The is in Shiga Prefecture, Japan. It was founded in 1996. The theme of the museum is "relationship between lakes and people" and introduces the nature and culture of Lake Biwa, the largest and oldest lake in Japan. The Lake Biwa Museum's aquari ...

in Kusatsu are also of interest. The Lake Biwa Marathon takes place in Ōtsu, the city at the southern end of the lake, annually since 1962.

Natural history

Lake Biwa is of

tectonic Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents ...

origin and is one of the world's oldest lakes, dating to at least 4 million years ago.Tabata, R.; Kakioka, R.; Tominaga, K.; Komiya, T.; Watanabe, K. (2016).
Phylogeny and historical demography of endemic fishes in Lake Biwa: the ancient lake as a promoter of evolution and diversification of freshwater fishes in western Japan.
' Ecology and Evolution 6(8): 2601–2623. This long uninterrupted age has allowed for a notably diverse

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

to evolve in the lake. Naturalists have documented more than 1000 species and subspecies in the lake, including about 60 endemics. Lake Biwa is an important place for

water birds A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in freshwater ecosystems, although others make no distinction from seabi ...

. About 5,000 water birds visit Lake Biwa every year. There are 46 native fish species and subspecies in the lake,Kawanabe, H.; Nishino, M.; and Maehata, M., editors (2012). ''Lake Biwa: Interactions between Nature and People.'' pp 119-120. including 11 species and 5 subspecies that are endemic or near-endemic. The endemic species are five

cyprinids Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest vert ...

('' Carassius cuvieri'', ''

Gnathopogon caerulescens ''Gnathopogon caerulescens'' is a species of ray-finned fish in the genus ''Gnathopogon'' endemic to Lake Biwa is the largest freshwater lake in Japan, located entirely within Shiga Prefecture (west-central Honshu), northeast of the former ...

'', '' Ischikauia steenackeri'', ''

Opsariichthys uncirostris ''Opsariichthys uncirostris'' is a species of cyprinid in the genus '' Opsariichthys''. It inhabits Siberia, China, Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38 ...

'' and '' Sarcocheilichthys biwaensis''), a true loach ('' Cobitis magnostriata''), two

gobies Gobiidae or gobies is a family of bony fish in the order Gobiiformes, one of the largest fish families comprising more than 2,000 species in more than 200 genera. Most of gobiid fish are relatively small, typically less than in length, and the ...

(''

Gymnogobius isaza ''Gymnogobius'' is a genus of gobies found in marine, brackish and fresh waters of Asia and the western Pacific Ocean. Species There are currently 16 recognized species in this genus: * '' Gymnogobius breunigii'' ( Steindachner, 1879) * '' Gymno ...

'' and ''

Rhinogobius biwaensis ''Rhinogobius'' is a genus of primarily freshwater gobies native to tropical and temperate parts of eastern Asia. Most are small, streamlined in shape, and often sexually dimorphic. Few are of commercial importance, but ''R. duospilus'' is fair ...

''), two silurid catfish (''

Silurus biwaensis ''Silurus biwaensis'', the giant Lake Biwa catfish or ''Biwako-o'namazu'' (ビワコオオナマズ (Japan)), is a large predatory catfish species endemic to Lake Biwa in Japan. Description The giant Lake Biwa catfish is very similar to wels ca ...

'' and '' S. lithophilus'') and a cottid (''

Cottus reinii ''Cottus reinii'' is a species of fish in the family Cottidae. It is endemic to Lake Biwa is the largest freshwater lake in Japan, located entirely within Shiga Prefecture (west-central Honshu), northeast of the former capital city of Ky ...

''). The

Biwa trout The Biwa trout (''Oncorhynchus rhodurus'') is an anadromous salmonid fish of the genus ''Oncorhynchus'', endemic to Lake Biwa in Shiga Prefecture, Japan, but also introduced to Lake Ashi and Lake Chūzenji. While called trout, the fish is most ...

is also endemic to the lake, but some maintain that it is a subspecies of the widespread

masu salmon The masu salmon (''Oncorhynchus masou''), also known as masu ( ja, マス, , trout) or in Japan, is a species of salmon belonging to the genus '' Oncorhynchus'', found in the North Pacific along Northeast/East Asian coasts from the Russian Far ...

rather than a separate species. The remaining endemic fish are subspecies of '' Carassius auratus'', ''

Cobitis minamorii ''Cobitis minamorii'' is a species of fish in the family Cobitidae found in the rivers flowing into Seto Inland Sea, San'yō district, western Honshu , historically called , is the largest and most populous island of Japan. It is located ...

'', '' Sarcocheilichthys variegatus'' and '' Squalidus (chankaensis) biwae''. Lake Biwa is also the home of a large number of

molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ...

, including 38 freshwater snails (19 endemic) and 16 bivalves (9 endemic). Recently the

biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...

of the lake has suffered greatly due to the invasion of foreign fish, the

black bass Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white have o ...

and the bluegill. Bluegill were presented to the

Emperor An emperor (from la, imperator, via fro, empereor) is a monarch, and usually the sovereignty, sovereign ruler of an empire or another type of imperial realm. Empress, the female equivalent, may indicate an emperor's wife (empress consort), ...

and later freed in the lake as a food source for other fish. Black bass were introduced as a

sport fish Game fish, sport fish or quarry refer to popular fish pursued by recreational anglers, and can be freshwater or saltwater fish. Game fish can be eaten after being caught, or released after capture. Some game fish are also targeted commercial ...

. In July 2009, a

largemouth bass The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, bu ...

weighing 10.12 kg (22 pounds, 4 ounces) was caught from the lake by Manabu Kurita. It has been officially certified by the

International Game Fish Association The International Game Fish Association (''IGFA'') is the leading authority on angling pursuits and the keeper of the most current World Record fishing catches by fish categories. Fishermen who are sport fishers are careful to follow their string ...

(IGFA) to tie the largemouth bass

world record A world record is usually the best global and most important performance that is ever recorded and officially verified in a specific skill, sport, or other kind of activity. The book ''Guinness World Records'' and other world records organization ...

held solely by George Perry for 77 years.

Archaeology

The Awazu site, a submerged

Shell midden A midden (also kitchen midden or shell heap) is an old dump for domestic waste which may consist of animal bone, human excrement, botanical material, mollusc shells, potsherds, lithics (especially debitage), and other artifacts and eco ...

, is an important

archaeological site An archaeological site is a place (or group of physical sites) in which evidence of past activity is preserved (either prehistoric or historic or contemporary), and which has been, or may be, investigated using the discipline of archaeology a ...

of the Jōmon period. It goes back to the beginning of the Initial Jōmon period (ca. 9300 BP). It lies near the southern end of Lake Biwa, close to Otsu City, at a depth of 2 to 3 meters from the bottom.Francesco Menotti, Aidan O'Sullivan
The Oxford Handbook of Wetland Archaeology.
OUP Oxford, 2013. p.181 The site shows the use of plant and animal food resources by the Jōmon people. It also demonstrates the importance of nut consumption in this period. Shell Midden No. 3 is dated to the Middle Jōmon period. An abundance of

horse chestnut The genus ''Aesculus'' ( or ), with species called buckeye and horse chestnut, comprises 13–19 species of flowering plants in the family Sapindaceae. They are trees and shrubs native to the temperate Northern Hemisphere, with six species n ...

s were uncovered here (about 40% of their total estimated diet). This indicates that, by this later period, a sophisticated processing technology was mastered in order to remove the harmful

tannic acid Tannic acid is a specific form of tannin, a type of polyphenol. Its weak acidity ( pKa around 6) is due to the numerous phenol groups in the structure. The chemical formula for commercial tannic acid is often given as C76H52O46, which corresp ...

, and make this food safe for consumption. Ishiyama is another such site of the Early Jōmon period on Lake Biwa.

Environmental legislation

Various environmental laws cover Lake Biwa:

Eutrophication prevention

At the prefectural level, Eutrophication Control Ordinance was enacted in 1979. It was intended to control the use of synthetic detergents by companies and residents alike and followed a successful citizens' campaign known as the Soap Movement, which had emerged from women's consumer groups earlier in the 1970s.Kira, T., Ide, S., Fukada, F., Nakamura, M. (2005
Lake Biwa: Experience and Lessons Learned Brief.
International Lake Environment Committee Foundation, Shiga, Japan. Legislation to prevent

eutrophication Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytopla ...

was enacted in 1981 and first enforced on July 1, 1982; therefore, this day is called "". The legislation established standards for the

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

and

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

levels for agricultural, industrial, and household water sources emptying into the lake. They also banned people from using and selling synthetic detergents which contain phosphorus.

Wetlands protection

The lake was designated as a

UNESCO The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations (UN) aimed at promoting world peace and security through international cooperation in education, arts, sciences and culture. It ...

Ramsar Wetland (1993) in accordance with the

Ramsar Convention The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar site, Ramsar sites (wetlands). It is also known as the Convention on W ...

. The object of this treaty is to protect and sensibly use internationally valuable wetlands. The Kushiro marsh ( 釧路湿原, Kushiro Shitsugen) in Japan is under this treaty now.

Conservation of Reed Vegetation Zones

Reed Reed or Reeds may refer to: Science, technology, biology, and medicine * Reed bird (disambiguation) * Reed pen, writing implement in use since ancient times * Reed (plant), one of several tall, grass-like wetland plants of the order Poales * ...

colonies on the shore form give Lake Biwa its characteristic scenery. The reeds play an important role in purifying water as well as providing habitat for birds and fish. At one time there were large areas of reeds along the shores of Lake Biwa, which local government surveys recently found to have halved in size due to encroaching development. This Shiga Ordinance for the Conservation of Reed Vegetation Zones to protect, grow, and utilize the reed beds has been in force since 1992.

Gallery

File:Biwako Quasi-National Park Omihachiman06n3200.jpg, Lake Biwa at Chomeiji-cho,

Ōmihachiman 260px, City Hall 260px, Traditional buildings Preservation Area is a city located in Shiga Prefecture, Japan. , the city had an estimated population of 82,233 in 34747 households and a population density of 570 persons per km². The total are ...

File:三井寺疎水 - panoramio.jpg, Lake Biwa Canal File:Mangetsuji Otsu Shiga02n4500.jpg,

Mangetsu-ji is a temple beside Lake Biwa in Ōtsu, Shiga Prefecture, Japan. The Heian period statue of Shō Kannon is an Important Cultural Property. The temple, specifically the Ukimidō "floating temple" hall, features in one of the remaining views of ...

temple, one of the Eight Views of Omi File:Michigan - Lake Biwa, Japan - DSC07330.JPG, A pleasure boat from

Port File:Chikubujima.jpg,

File:Biwa Lake.jpg, Sunrise over Lake Biwa File:Port_of_imazu01s3200.jpg, Imazu Port, Takashima File:Nagahama_port01s3872.jpg, Nagahama Port File:Biwa lake.jpg, Lake Biwa (Biwa-ko) File:Kusatsu Reisho Tokaido.jpg,

Hiroshige Utagawa Hiroshige (, also ; ja, 歌川広重 ), born Andō Tokutarō (; 1797 – 12 October 1858), was a Japanese ''ukiyo-e'' artist, considered the last great master of that tradition. Hiroshige is best known for his horizontal-format l ...

File:Biwako-from-Kitahira-Toge-Pass-2014-Luka-Peternel.jpg, Lake Biwa from Kitahira-Tōge Pass

Explanatory notes

References

External links

Department of Lake Biwa and Environment, Shiga Prefecture

Lake Biwa Environmental Research Institute

Lake Biwa Museum

Ramsar site database

go.biwako - Travel Guide of Shiga Prefecture, Japan

Lake Biwa (World Wildlife Fund)

Review of Criodrilidae (Annelida: Oligochaeta) including Biwadrilus from Japan

Japan's Secret Garden NOVA / PBSFishing World Records
{{Authority control Ancient lakes Biwa Biwa Biwa Landforms of Shiga Prefecture Jōmon period Ōmihachiman, Shiga