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Lake Biwa

Coordinates: 35°15′18″N 136°04′48″E / 35.25500°N 136.08000°E / 35.25500; 136.08000
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(Redirected from Biwako)
This article is about the lake in Japan. For the album by Wadada Leo Smith, see Lake Biwa (album).

Lake Biwa
琵琶湖 (Japanese)
Lake Biwa from space
Lake Biwa is located in Japan
Lake Biwa
Lake Biwa
Lake Biwa is located in Shiga Prefecture
Lake Biwa
Lake Biwa
LocationShiga Prefecture, Japan
Coordinates35°15′18″N 136°04′48″E / 35.25500°N 136.08000°E / 35.25500; 136.08000
TypeAncient lake, tectonic, freshwater
Primary inflows118 rivers
Primary outflowsSeta River
Catchment area3,174 km2 (1,225 sq mi)
Basin countriesJapan
Max. length63.49 km (39.45 mi)
Max. width22.8 km (14.2 mi)
Surface area670.3 km2 (258.8 sq mi)[1]
Average depth41 m (135 ft)
Max. depth104 m (341 ft)[1]
Water volume27.5 km3 (6.6 cu mi)[1]
Residence time5.5 years
Shore length1235.2 km (146.1 mi)
Surface elevation85.6 m (281 ft)
IslandsChikubu, Takeshima, Okishima (inhabited)
SettlementsHigashiōmi, Hikone, Kusatsu, Maibara, Moriyama, Nagahama, Ōmihachiman, Ōtsu, Takashima, Yasu
Official nameBiwa-ko
DesignatedJune 10, 1993
Reference no.617[2]
1 Shore length is not a well-defined measure.
Lake Biwa aerial view

Lake Biwa (琵琶湖, Biwa-ko) is the largest freshwater lake in Japan. It is located entirely within Shiga Prefecture (west-central Honshu), northeast of the former capital city of Kyoto.[3] Lake Biwa is an ancient lake, over 4 million years old.[1] It is estimated to be the 13th oldest lake in the world.[4] Because of its proximity to the country's historical capital Kyoto, references to Lake Biwa appear frequently in Japanese literature, particularly in poetry and in historical accounts of battles.

Name

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The name Biwako was established in the Edo period. 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 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 and the shape of the lake is similar to that of the biwa, her favorite instrument."[5]

The lake was formerly known as Aumi (淡海, Freshwater Sea) or Chikatsu Awa-umi (Freshwater Sea Near [the Capital]). The current pronunciation of this word has become Ōmi, as in the name of Ōmi Province. The lake is also called Nio no Umi (鳰の海, "Little Grebe Lake") in literature.

Area and use

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The area of this lake is about 670 km2 (260 sq mi).[6] Small rivers drain from the surrounding mountains into Lake Biwa, and its main outlet is the Seta, which later becomes the Uji, combining with the Katsura and Kizu to become the Yodo River, which flows into the Seto Inland Sea at Osaka Bay.

It serves as a reservoir for the cities of Kyoto and Ōtsu and is a valuable resource for nearby textile industries. It provides drinking water for about 15 million people in the Kansai region. Lake Biwa is a breeding ground for freshwater fish, including trout, and for the pearl culture industry.

The Lake Biwa Canal, built in the late 1890s and later expanded during the Taishō era, played a crucial role in the revival 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 northwestern shore, in particular Shiga and Ōmi-Maiko. The Mizunomori Water Botanical Garden and the Lake Biwa Museum in Kusatsu are also of interest.

The Lake Biwa Marathon took place annually in Ōtsu, the city at the southern end of the lake, from 1962 until 2021.

Natural history

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The giant Lake Biwa catfish is the largest predatory fish in the lake and is found nowhere else.

Lake Biwa is of tectonic origin and is one of the world's oldest lakes, dating to at least 4 million years ago (mid-Pliocene).[1] This long, uninterrupted period has allowed for a notably diverse ecosystem to evolve in the lake. Naturalists have documented more than 1000 species and subspecies in the lake, including about sixty endemics.[1] Lake Biwa is an important place for water birds. About 5000 water birds visit Biwa every year.

There are 46 native fish species and subspecies in the lake,[7] including eleven species and five subspecies that are endemic or near-endemic.[1] The endemic species are five cyprinids (Carassius cuvieri, Gnathopogon caerulescens, Ischikauia steenackeri, Opsariichthys uncirostris and Sarcocheilichthys biwaensis), a true loach (Cobitis magnostriata), two gobies (Gymnogobius isaza and Rhinogobius biwaensis), two silurid catfish (Silurus biwaensis and S. lithophilus) and a cottid (Cottus reinii).[1][7]

The Biwa trout is also endemic to the lake, but some maintain that it is a subspecies of the widespread masu rather than a separate species.[1][7] The remaining endemic fish are subspecies of Nigorobuna, Cobitis minamorii, Sarcocheilichthys variegatus and a local variety of Khanka gudgeon.[a][1][7]

Lake Biwa is also the home of a large number of molluscs, including 38 freshwater snails (19 endemic) and 16 bivalves (nine endemic).[8]

Recently, the biodiversity of the lake has suffered greatly due to invasive species of foreign fish, in particular black bass and the bluegill. Black bass were introduced in 1925 as a game fish. In July 2009, a largemouth bass weighing 10.12 kg (22 lb 4 oz) was caught from Biwa by Manabu Kurita. It has been officially certified by the International Game Fish Association (IGFA) to tie the largemouth bass world record, held solely by George Perry for 77 years.[9][10] During a visit to Chicago in 1966, Mayor Richard J. Daley presented live bluegills to then-Prince Akihito, an avid ichthyologist; they were later released into lakes in Japan as a game fish.[11]

“At that time, we had not experienced any serious invasive species problems and bluegill did not look dangerous according to its feeding habits, not being a fierce piscivore,” says Nakai Katsuki,[b] a Japanese research scientist at the Lake Biwa Museum who has studied invasive North American fish species in Japan’s Shiga Prefecture since 1989.[11]

Archaeology

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The Awazu site, a submerged shell midden, is an important archaeological site of the Jōmon period. It goes back to the beginning of the Initial Jōmon period (c. 9300 BCE). It lies near the southern end of Lake Biwa, close to Ōtsu, at a depth of two to three meters from the bottom.[12]

The site shows the use of plant and animal food resources by the Jōmon people. It also highlights the significance of nut consumption during this period.

Awazu Midden 3 is dated to the Middle Jōmon (3520–2470 BCE). An abundance of horse chestnuts 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, and make this food safe for consumption.[13]

Ishiyama-dera is another such site, but dating to the Early Jōmon (5000-3520 BCE) on Lake Biwa.[12]

Environmental legislation

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Various environmental laws cover Lake Biwa:

Eutrophication prevention

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Main article: Environmental movement

At the prefectural level, the Eutrophication Control Ordinance was enacted in 1979. It was intended to control industrial pollution from the use of synthetic detergents by companies and residents alike, following a successful citizens' campaign known as the Soap Movement, which had emerged from women's consumer groups earlier in the 1970s.[14]

Legislation to prevent eutrophication was enacted in 1981 and first enforced on July 1, 1982; therefore, this day is called "Lake Biwa Day (びわ湖の日, Biwako no Hi)". The legislation established standards for the nitrogen and phosphorus levels for agricultural, industrial, and household water sources emptying into the lake. They also banned the use and sale of synthetic detergents containing phosphorus.

Wetlands protection

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The lake was designated as a UNESCO Ramsar Wetland (1993) in accordance with the Ramsar Convention.[15] 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

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Reed colonies on the shore 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.

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See also

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Explanatory notes

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  1. ^ The subspecies differentiation may not be recognized, for example by the current FishBase.
  2. ^ "中井 克樹 (Nakai Katsuki) - マイポータル - researchmap". researchmap.jp.

References

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  1. ^ a b c d e f g h i j 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.
  2. ^ "Biwa-ko". Ramsar Sites Information Service. Retrieved April 25, 2018.
  3. ^ "Biwa, Lake". Academic Dictionaries and Encyclopedias.
  4. ^ "Ancient lakes of the world". Christopher M. Free. Archived from the original (website) on February 9, 2020. Retrieved January 20, 2020.
  5. ^ Yoshihiro Kimura (2001). Biwako -sono koshō no yurai- [Lake Biwa, the origin of its name]. Hikone: Sunrise Publishing. ISBN 4-88325-129-2
  6. ^ Kunimune, Yoshio; Mitsunaga, Yasushi; Komeyama, Kazuyoshi; Matsuda, Masanari; Kobayashi, Toru; Takagi, Tsutomu; Yamane, Takeshi (2011). "Seasonal distribution of adult crucian carp nigorobuna Carassius auratus grandoculis and gengoroubuna Carassius cuvieri in Lake Biwa, Japan". Fisheries Science. 77 (4): 521–532. Bibcode:2011FisSc..77..521K. doi:10.1007/s12562-011-0354-7. S2CID 44186839.
  7. ^ a b c d Kawanabe, H.; Nishino, M.; and Maehata, M., editors (2012). Lake Biwa: Interactions between Nature and People. pp 119-120. ISBN 978-94-007-1783-1
  8. ^ Segers, H.; and Martens, K; editors (2005). The Diversity of Aquatic Ecosystems. p. 46. Developments in Hydrobiology. Aquatic Biodiversity. ISBN 1-4020-3745-7
  9. ^ "Bass, Florida (Micropterus salmoides)". IGFA World Records. Retrieved April 3, 2019.
  10. ^ "Game & Fish". May 12, 2015. Retrieved April 3, 2019.
  11. ^ a b Elliott, Christian (January 11, 2022). "The prince, the mayor, and the U.S. fish that ate Japan". National Geographic. Archived from the original on March 30, 2023. Retrieved July 15, 2025. When Crown Prince Akihito visited Chicago on October 3, 1960, his sole request was to visit Shedd Aquarium. Then Mayor Richard J. Daley, an avid angler, presented the prince with a gift that he scooped with a net from one of the tanks himself: 18 bluegills, the official Illinois state fish. The 26-year-old future emperor was already a passionate ichthyologist, and he planned to stock the exotic fish in the moat surrounding his palace, according to accounts in the Chicago Tribune at the time. At windy Chicago O'Hare International Airport the next day with Princess Michiko, Akihito bid the city farewell, carrying a gift that he couldn't have imagined would cause a decades-long ecological crisis in his homeland. In the intervening six decades, the bluegills became an invasive, species-destroying nightmare, crowding Japanese freshwater lakes and rivers and destroying native fish biodiversity, says Kenji Saitoh, a researcher at the country's Fisheries Resources and Education Agency. Fortunately, science has marched on in 60 years. Now, Japanese geneticists are experimenting with the gene editing wizardry of CRISPR to sterilize the invasive bluegills. If the initiative succeeds, wildlife managers could use the same technique to rid the U.S. of damaging aquatic invasives such as the Asian carp. In Japan, the public is ambivalent about the bluegills and wary of genetic efforts to curtail them, and it's easy to see why. The 60-year history of bluegill in Japan is a cautionary tale about human intervention on all sides. The invasion begins When he arrived home after his 1960 U.S. tour, Akihito asked Japan's national Agency of Fisheries to breed the 15 captive bluegills that survived the trans-Pacific journey, in hopes of releasing them into the wild as a new game fish, nicknamed the "prince fish" in his honor. In 1966, the bluegills' offspring were deposited into Lake Ippeki-ko outside Ito City in Japan's Shizuoka Prefecture. Three years later, a stone monument was placed on the shore to celebrate the prince fish's successful introduction. More bluegills were released into freshwater ecosystems across Japan. "At that time, we had not experienced any serious invasive species problems and bluegill did not look dangerous according to its feeding habits, not being a fierce piscivore," says Nakai Katsuki, a Japanese research scientist at the Lake Biwa Museum who has studied invasive North American fish species in Japan's Shiga Prefecture since 1989.
  12. ^ a b Menotti, Francesco; O'Sullivan, Aidan (2013). The Oxford Handbook of Wetland Archaeology. OUP Oxford. p. 181. ISBN 978-0-19-957349-3.
  13. ^ Habu, Junko; Matsui, Akira; Yamamoto, Naoto; Kanno, Tomonori (2011). "Shell midden archaeology in Japan: Aquatic food acquisition and long-term change in the Jomon culture" (PDF). Quaternary International. 239 (1–2): 19–27. Bibcode:2011QuInt.239...19H. doi:10.1016/j.quaint.2011.03.014. ISSN 1040-6182.
  14. ^ Kira, T., Ide, S., Fukada, F., Nakamura, M. (2005) Lake Biwa: Experience and Lessons Learned Brief. International Lake Environment Committee Foundation, Shiga, Japan.
  15. ^ "Biwa-ko". Ramsar Sites Information Service. Retrieved May 31, 2025.
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Wikimedia Commons has media related to Lake Biwa.
Wikivoyage has a travel guide for Lake Biwa.
Wikisource has the text of the 1905 New International Encyclopedia article "Biwa".
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