Lake Võrtsjärv ( ; ) is a

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

in southern

Estonia Estonia, officially the Republic of Estonia, is a country in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the Baltic Sea across from Sweden, to the south by Latvia, and to the east by Ru ...

with an area of 270 km² (104 mi²). It is the second largest lake in Estonia (after

Lake Peipus Lake Peipus is the largest trans-boundary lake in Europe, lying on the international border between Estonia and Russia. The lake is the fifth-largest in Europe after Lake Ladoga and Lake Onega (in Russia), Lake Vänern (in Sweden), and Lake ...

), and the largest lake situated entirely within Estonia. The shallow lake is 33.7 m (111 ft) above sea level. The

Emajõgi The Emajõgi (; meaning 'mother river') is a river in Estonia which flows from Võrtsjärv, Lake Võrtsjärv through Tartu County into Lake Peipus, crossing the city of Tartu for . It has a length of . The Emajõgi is sometimes called the Suur E ...

river flows from Lake Võrtsjärv to Lake Peipus.

History

The lake basin existed before the last Ice Age, but was then transformed by moving ice sheets which partly eroded the lake wall and partly filled the depression with deposits. In its present form the lake has existed since the Middle Holocene. It was first mentioned in the

Livonian Chronicle of Henry The ''Livonian Chronicle of Henry'' () is a Latin narrative of events in Livonia (roughly corresponding to today's Estonia and Latvia) and surrounding areas from 1180 to 1227. It was written by a priest named Henry. Apart from some references ...

, where it is called ''Worcegerwe''.

Geography

The relatively low shores of the lake are swampy in the south and sandy in the north. On the eastern shore, there is a coastal abrasion near the village of Tamme; these cliffs have yielded a number of fossils of

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

fish, which have been compared to similar fossils found in

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

. There are a few small

islands This is a list of the lists of islands in the world grouped by country, by continent, by body of water, and by other classifications. For rank-order lists, see the #Other lists of islands, other lists of islands below. Lists of islands by count ...

in the southern part of the lake. Of these only Tondisaar and Pähksaar are permanent islands, while Ainsaar becomes a peninsula during low water and Heinassaar is submerged at high water. This is because of the lakes fluctuating

water level Water level, also known as gauge height or stage, is the elevation of the free surface of a sea, stream, lake or reservoir relative to a specified vertical datum. Over long distances, neglecting external forcings (such as wind), water level ten ...

, which changes with a mean annual amplitude of 1.4 m; this is about half of its 2.8 m average depth. From around November to April, the lake is covered with an ice sheet. Situated northeast of the lake is the Alam-Pedja Nature Reserve, the largest

nature reserve A nature reserve (also known as a wildlife refuge, wildlife sanctuary, biosphere reserve or bioreserve, natural or nature preserve, or nature conservation area) is a protected area of importance for flora, fauna, funga, or features of geologic ...

in Estonia.

Ecology

Around 35 species of fish are found in the lake, a few of which are commercially important. After a decline of valuable species during the 1950s and 1960s, some conservation measures were enforced which lead to an improvement in the situation. Today, around 400 t of fish are caught annually. Lake Võrtsjärv is the main catchment area for

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 20 families, 164 genera, and about 1000 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

in Estonia. However, fishing is entirely dependent on restocking with farmed glass eels, as eels are migratory and do no longer return in sufficient quantities to Europe. Due to declining numbers of natural eel, in 2017 the European Union's Agriculture and Fisheries Council decided on a three-month ban of eel fishing in the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...

during eel migratory season. Eel caught in the Baltic Sea had only accounted for a mere 700 kg the year before, as opposed to an average of 10.2-13.3 t per year in Lake Võrtsjärv. The lake and the nearby wetlands are also an important breeding ground for birds, as well as a staging area for

migratory birds Bird migration is a seasonal movement of birds between breeding and wintering grounds that occurs twice a year. It is typically from north to south or from south to north. Migration is inherently risky, due to predation and mortality. The ...

. In total, 213 bird species have been recorded around the lake. In recent decades,

eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...

of the lake has increased, with detrimental effects on biological diversity. This is thought to be mainly caused by a combination of poorly treated wastewater influx as well as phosphorus and nitrate runoff from agriculture. In addition, climatic fluctuations seem to have a stronger influence on the lake due to its shallow depth.

Tourism

The region is little known as a tourist destination internationally and, especially in the second half of the 20th century, the deteriorating water quality posed a continuous problem for both fishing and tourism development. However, more recently, in 2010, Võrtsjärv was voted European Destination of Excellence. There is a visitor centre and museum on the east shore of the lake. In 2016, the lake was the site of the WISSA World Championships in iceboating on the frozen lake. File:Jõesuu vaatetorn.jpg, Jõesuu watchtower on the northern shore of Lake Võrtsjärv File:Võrtsjärve rand.jpg, "The shore of Võrtsjärv" by Konrad Mägi. Oil on canvas. 1917 File:Tamme-paljand3.JPG, Tamme outcrop File:Valma.jpg, Võrtsjärv lake shore during an extremely low tide, near Valma (2006) File:Limnoloogia-jaam.JPG, Limnology Centre of the

Estonian University of Life Sciences The Estonian University of Life Sciences ( Estonian: ''Eesti Maaülikool'', EMÜ) is a public university located in Tartu, Estonia. Its roots trace back to 1802 when the Chair of Agriculture was founded in the University of Tartu. EMÜ is the fo ...

by Võrtsjärv, in Vehendi

References

External links

More information about eel fishing in the lakeTourism brochure from 2010 in Estonian and English, including information about Lake VõrtsjärvHistory of hydrological and biological investigations of lake Võrtsjärv
{{DEFAULTSORT:Vortsjarv Lakes of Estonia Lakes of Tartu County Lakes of Viljandi County Lakes of Valga County LVortsjarv