Lake Ohrid: The Oldest Lake in Europe

Lake Ohrid Stats

Geography

Lake Ohrid and the neighboring Lake Prespa were part of a group of Dessaret basins, which originated from a geotectonic depression during the Pleocene, about 5 million years ago, in the Western precinct of the Dinaric Alps. The lake occupies the South-Eastern part of Albania (110 km2) and the South-Western part of Macedonia (248 km2). It is the largest and is considered the most beautiful of the three Macedonian tectonic lakes.

There are only a few other lakes in the World which have similarly remote origins, such as Lake Baikal and Lake Tanganyika. Lakes rarely survive for such a long time, since they usually fill up with sediments. This process was delayed in Lake Ohrid’s case, due to its depth and small sediment inflow from its tributary streams. The Ohrid-Korca graben, at the Southern end of the lake, is still tectonically active and might compensate sedimentation by subduction. On the other hand, Lake Prespa might have dried up several times in the past as a result of its karstic underground activity. Lake Ohrid has been a center for limnological investigations for scientists since 1892.

Hydrology

The lake is fed by underground springs from the East, representing half of the inflow. 25% of the lake’s waters come from rivers and direct precipitation. The remaining part flows in from Lake Prespa, 10 kilometers to the South-East. Prespa spills its waters through mountain springs (such as Ostrovo and Biljana), thanks to the 150 meter elevation difference. Ostrovo arrives to the lake next to the Monastery of Sveti Naum, whilst Biljana flows in next to Ohrid Town.

40% of the lake’s waters evaporate; the rest flows out through the Black Drin River, which makes its way toward the North, crossing the border to Albania, and then flowing in to the Adriatic Sea. The Mediterranean climate and the lake’s small drainage basin of 2600 km2 lead to a long hydraulic residence time scale of ~70 years.

The waters move in a counter-clockwise direction along the lake’s shores. These movements are the result of the wind forcing and earth rotation, similar to the Ekman-phenomenon, a similar activity observed in the oceans. The dominant process in vertical water exchange is circular mixing during winter cooling. During an average winter only the top 150-200 meters of water are blended. The water below this layer is stably stratified by salinity, thus a complete collective mixing occurs only every seven years.

Regarding nutrient concentration and biological parameters the lake can be considered oligotrophic. Plunging rivers are mainly absent from Lake Ohrid.

In 1963 River Sateska was diverted into the lake, which dumped large quantities of stilt and tons of toxic waste into Lake Ohrid. Scientists affirm that the lake may be the most diverse in the World for its size.

Flora and Fauna

Lake Ohrid’s most impressive feature is its endemism, often being referred to as the “museum of living species”. It is home to a large number of endemic plants and animals, such as 20 species of phytoplankton and sessile algae, 2 plant species, 5 zooplanktons, 8 types of oyprinid fish and 176 diverse bottom fauna compontents. 73.5% of the total gastropod fauna is endemic to the Lake Ohrid basin.

There are also a number of exotic fish species which don’t cause problems among the endemic fish, which have adapted perfectly to the lake’s conditions regarding nutrient availability and greater living conditions in deeper waters. Out of the 21 native fish existing in Lake Ohrid, one-third of them are endemic, similarly to 80% of the 72 mollusc species. Foreign species reached the waters either through water bird or the migrated like the European eel.

The wetlands and the reed beds of the lake’s shores provide critical habitats for hundreds of thousands of wintering water birds, including some rare species like the ferruginous duck, spotted eagle, Eastern Imperial Eagle and the Dalmatian Pelican.

One of the most important endemic species is the Ohrid trout, which has been a favored delicacy since Roman times. The bleak’s scales are used for making Ohrid pearl. In 1935 a breeding program was initiated to artificially spawn and hatch the native Ohrid trout, creating an abundance of the fish species. The Galicica National Park, on the Macedonian side, has plenty of wild boars, bears and wolves.

History

Ohrid is one of the most ancient settlements on the European continent. The shores have been inhabited since prehistoric times. The first signs of humans were found at Dolno Trnovo and the Bay of Bones at Gradiste, both dating back to the Bronze Age, 12 000-7000 BC. The latter was reconstructed in modern times, but some related artefacts can be found on display at the Ohrid Museum.

After the Bronze Age, Brigians, Ohrygians and Enhelians lived on the lake’s shores. These tribed were later substituted by the Desaretes, who made their capital city Lychnidos, located in the heart of the Ohrid we see today. Lychnidos was founded and named by Cadmus the Phoenician, who created Thebes in the 14th century. He abdicated to favor his grandson, traveling to the North to fight for the Enhelians. It is said that when Lychnidos was founded, water levels were much lower compared to its level today.

Lychnidos has two different meanings in two different languages. In ancient Greek it signifies a “tower of lamps”, whilst in Phoenician it simply means “water reeds”.

In the 4th century BC the area was conquered by a Macedonian ruler called Philip II. In the late second century BC, Romans overcame the Lake Ohrid area. The region was further developed in Roman times, mostly by travelers who journeyed on the Via Egnatia, which passed through Lychnidos and Radoza. These travelers also brought Christian preachers with them.

In the 5th century AD the first basilicas were built in Lychnidos. Rumor has it that there were 12 of them, but only 6 have been discovered by archaeologists, of which the monastery of Saint Kliment at Plaosnik is the largest.

In 879 the Slavs started referring to the area as “Ohrid”, originating most probably from the words “vo hrid”, meaning “on a hill”. A few years later two missionaries, Kliment and Naum set up the first monastery, in which they taught Slaving, strengthening furthermore the region’s religious diversity. Over 3500 pupils attended the monastery. Kliment became a patron of the city and a saint, for three decades of work and initiating the Clement Slavic University. The Slavic education was spread from the 7th until the 19th century.

In the 10th century Tsar Samoil moved his empire’s capital to Ohrid, also making it the head of its own autocephalous patriarchate. In 1014 he was defeated by Basilius II, who introduced Byzantine rule over Lake Ohrid. Even though the patriarchate of Ohrid was reduced to archbishopric during the Byzantine Empire, it still remained a strong religious center. At the end of the 16th century the jurisdiction of Archbishopric of Ohrid went as far as the Orthodox communities in Dalmati, Venice, Malta and Sicily.

Because of the pristine nature environment combined with the abundance of historical sites, the lake has become a target for national and international tourists by the ‘80s, when nearly 200 000 tourists went on literal pilgrimage on the lakeside. Under the Yugoslav rule some development was made in the tourism sector, since Tito owned a few summer residences on the shores of Lake Ohrid.  During the interethnic conflicts tourism in the area was in a downfall and collapsed in 2001. It is slowly recovering these days.

Human Settlements and Ecological Impact

Three main cities (Ohrid, Pogradec and Struga), as well as many towns and villages (such as Lin, Pojska and Tushemisht) lie on the coastline. Lake Ohrid’s catchment area houses a population of 170 000 inhabitants, of which 130 000 live directly on the lake’s shore. The population grew by 100 000 in the past 50 years, putting the lake and its ecosystem under a bit of pressure.

Besides the increase in population, reed bed destruction and intense pollution also endanger Lake Ohrid. The shallower parts are under most threat, since they are especially rich in endemic bottom fauna. There are fishing regulations especially regarding the Ohrid trout species, which has dropped significantly in the past decades. There are only a limited number of fishing licenses given to fishermen each season, in attempt to regulate fishing on the premises.

The growth of the population raises questions regarding eutrophication as a result of pollution. Shifts from endemic to common European species have been recently remarked. Water transparency has also been reduced in the past decades because of higher nutrient levels, causing a decrease in oxygen levels. Because of the long water resistance time, it might be another ten years until we can witness the results of this heavy pollution. These effects could easily be amplified by global warming.

The lake was declared a UNESCO World Heritage Site in 1979. In 2010 NAS named one of Titan’s lakes after Lake Ohrid. In 2014 the Ohrid-Prespa Transbounday Reserve between Macedonia and Albania has been included in UNESCO’s World Network of Biosphere Reserves.

Tourism and Recreation

Lake Ohrid is fast becoming a prime tourist destination due to its graceful hills dotted with beautiful churches and a medieval castle, all overlooking the clear lake. The peak season is between the 15th of July and the 15th of August, when the largest music festival of Macedonia takes place around the lake. Booking ahead is required this time of year, even though there are plenty of hotels, campsites and guesthouses along the lakeshores. The area is mainly known for family-centric hospitality, especially in the Tushemisht area.

The lake is often referred to as the Macedonian equivalent of the Croatian Adriatic, especially because of the wide variety in water activities. Swimming, speed boating, sunbathing, scuba diving, waterskiing and fishing are preferred activities.

More than 40 churches can be found on the shores of Lake Ohrid, of which many are very old constructions, such as Saint Sophia Church (from the 11th century), Bogorodica Perivlepta (13th century), Saint John Kaneo (13th century) and Saint Pantelejmon-Plaoshnik. The small Old Bazaar, the Antique Theater and the fortress of Ohrid (Tsar Samoil Fortress) are also important man-made tourist attractions. Besides the Summer Festival, Ohrid also hosts the annual Swimming Marathon and the Balkan Folklore Festival.

Caving, hiking and paragliding are favored activities in Galicica National Park. The lake springs at Sveti Naum and the cave churches at Kalista and Radozda also offer an interesting sight. Locals can also put together daytrips by boat, jeep, donkey or on foot to the surrounding villages.