Längsee

General Description

Resting place for migrant birds. The Längsee is a small extensively natural left bathing lake, whose southern shore is built up. The migratory birds make a rest at the lake on their way to the winter quarters. This especially delights birds` friends.
The Längsee with an area of about 75 ha and a maximal depth of 21,4 m belongs to the smaller valley lakes of Carinthia. It is situated in a flat valley trough 550 m above sea level and is bordered by wood covered hill slopes in the east and west. Like most of the Carinthian lakes it was formed glacially. It is the vestige of a much larger former lake. With the exception of the western shore that is falling in rather steeply, the shores are flat, boggy and covered with a thin reed belt.

Little water courses out of the surrounding slopes, which often dry- out, and the ground water stream feed the lake. Because of the weak flowing-through the time for the water renewal is 11 years. The runoff, the Lavabach, has an average water volume of only 30l/s. It drains to the south, passing an extended moor.

Excellent bathing water quality. Limnologically the Längsee is to be related to the lake types that are poor in nutrients, oligotroph, with a high bathing water quality. It is one of the most hallow meromictic lakes with an always stagnating depth layer, free of oxygen. This phenomenon traces to the wind calmed basin state of the lake. The weak streaming through as well as the early summer periods, which are poor of winds, cause a quicker warming up and reaching temperatures up to 27 °C. In winter the lake regularly has a closed ice sheet.

Breeding ground for birds. The Längsee is of great importance for the spring and autumn birds` passage, because it is situated near the main migration lines. At this lake small bitterns are breeding every year.

The Längsee is part of the Längsee landscape protection area of about 396 ha (LGBl.35/70).

Tourism

Cultural Life. The Convent of St. Georgen, a monastery of the diocese of Gurk, is situated in the east of the Längsee and houses an educational establishment and a hotel. In the south of the lake you can see the picturesque Castle of Hochosterwitz. It is worth climbing up through the 14 different gates. Or you can easily conquer the 150 meters up using the slope elevator, which starts at the parking place.

Fish Stock

13 species of fish:

Pike (Esox lucius)
Bass (Perca fluviatilis)
Eel (Anguilla anguilla)
Catfish (Silurus glanis)
Chub (Leuciscus cephalus)
Bitterling (Rhodeus sericeus amarus)
Bream (Abramis brama)
Carp (Cyprinus carpio)
Bleak (Alburnus alburnus)
Roach (Rutilus rutilus)
Common rudd (Scardinius erythrophthalmus)
Tench (Tinca tinca)
Pike-perch (Sander lucioperca)

World record pike. Fish-biologically the lake can be called a flat bream and pike type. The most frequent species of fish is the bream, which has extreme lengths of more than 50 cm. But also pike can grow very large here. In May 1990 the world record pike brought 29 kg onto the scales. The pike population probably has developed like this because of the decreasing of the pike perch. In 1983/84 after a very long winter a total decrease of oxygen happened and caused a fish dying in the lake. The pike perch population has strongly decreased and so the food rivalry for the pike diminished. Besides the pike compared with the pike perch prefers clear water. Formerly the pike perch was the most remarkable fish in the lake. In spring 2002 they found an increased spawning of pike perch on the “Zandernestern” again.

The profit by fishing in the Längsee is at about 20 kg/ha and year. The bass in the Längsee reach lengths of 30 cm and weights of 1 kg. There is also a relatively good stock of catfish. Divers report about catfish with more than 2 m.

Fish stocking. Many signs tell us that the carp population does not multiply in a natural way, but is maintained by regular stocking, at which must be said that the species grows well. Another spectacular sign is the good growing of red fins, which can reach lengths of more than 40 cm. In the 1960s they stocked 60.000 heads of glass eels, but they were decimated by the fish dying of 1983/84.
At the beginning of the 1970s a number of grass carp was stocked, but they cannot be documented any more. In the end of the 1960s they stocked rainbow trouts and at the end of the last century they stocked char. First they grew up well, but then they disappeared, because this lake is not suitable for coarse fish. Hartmann (1898) has observed burbot in the lake. They now can be found in the runoff (ZWANDER et. al., 1994).
 
In the runoff, the Lavabach, there live chub, bass, roach, tench, burbot, catfish and brown trout. The structure of the fish species changes in the course of a year. So in spring bass dominate, while in summer the chub increase. In autumn there are also more and more small catfish.

Fishing Permits

Municipal Office St. Georgen am Längsee, phone: +43 (0) 4213 2192

Bildungshaus St. Georgen a. Längsee, phone: +43 (0) 4213 2046

Gasthof Schratt, phone: +43 (0) 4213 2136

Schlossparkbuffet, phone: +43 (0) 4213 3042

Ferienhof Haberzettl, phone: +43 (0) 4267 397

Remedial Actions

Catchment Area

Valuation of the ecological status. The catchment area of the lake is the region, out of which the surface- and the underground waters flow into the lake. The borders of this area are formed by the watershed. The cartographic description of these catchment areas referring to the usage is the base for the valuation of the ecological status in regard to the general water instructions (WFD). All the fundamental data are registered in a data bank. With the help of the software Arc View GIS, version 3.2, the analysis of the geographic information took place. The topographic state, the natural vegetation and the anthropogen usage of the catchment area deliver important information about nutrient- and pollutant burdens.

Vegetation

There are 40 different forms of vegetation.
The descriptions are out of HARTL, STERN & SEGER, 2001, “The Map of Carinthia`s Current Vegetation”. The geo-referenced data out of this work were blended with the catchment area and transferred into the data bank.
They differentiate 40 forms of vegetation. To have a better view on the results they are comprehended in the following tabulation in these main groups:
intensively used agricultural areas, farming green-land, forests, surface- waters, built up areas, Alps and others.

Utilization

34 forms of utilization in the catchment area. They were geo-referenced and blended with the digital register (DKM) out of 2003.The granted data were transmitted into a data bank and now afford information about the dimensional distribution of the different forms of utilization. The 34 forms of utilization have also been comprehended in the main groups like it has been done for the vegetation groups.