Ohrid Lake

The lake is one of the largest biological reserves in Europe, possessing unique flora and fauna which are extinct elswere. Only Lake Ohrid, Lake Tanganyka, Lake Caspi, and Lake Baikal are believed to have been formed during the Tertiary Period some 2-4 million years ago, and hence these lakes are characterized by unique flora and fauna distinct to that period. Due to its age, many of Lake Ohrid’s aquatic species are endemic including ten of the seventeen fish species. In addition, there are five particular endemic species which are restricted to small areas of the Lake such as special various birds, as well as four fish spawning grounds. Because of its rich history and unique flora and fauna, Lake Ohrid was declared a UNESCO World Cultural and Natural heritage Site in 1980. A clear danger exists to maintaining the long-term ecological stability of Lake Ohrid, unless action is taken to improve environmental management of the catchment area and the shoreline to prevent the accumulation of pollutants in the lake. Despite a number of remedial measures, less than 25% of wastewater in the catchment is treated. These conditions have led to an increase in the total phosphorus concentration of about 0.25mg/m3 over the past decade with a mean contrentacion estimated at between 7-8 mg/m3. The current loading of dissolved phosphorus is approximately 150 tons per year, and this would need to be reduced to 100 tons per year to keep the main concentration of phosphorus below 7 mg/m3.