Worldwide, there are only a few lakes with similarly remote origins with Lake Baikal and Lake Tanganyika being the most famous. Most other, short-lived lakes have a life span of less than 100,000 years before they are eventually filled up with sediments. It is believed that in the case of Lake Ohrid this process was delayed by its great depth and small sediment input from its filtered spring inflows. Moreover the Ohrid-Korca graben to the south of the lake is still tectonically active and might compensate sedimentation by subduction. In contrast to Lake Ohrid, Lake Prespa is likely to have turned dry several times in its history, as a result of its karstic underground.
     While Lake Ohrid is special as such, by far the most spectacular quality is its impressive endemism. Similar to Lake Baikal or Lake Tanganyika, Lake Ohrid harbors endemic species covering the whole food-chain, from phytoplankton and sestile algae (20 species; e.g., Cyclotella fottii), over plant species (2 species; e.g., Chara ohridana), zooplankton (5 species; e.g., Cyclops ochridanus), cyprinid fish (8 species; e.g., Pachychilon pictus), to predatory fish (two trout species; the Ohrid trout complex Salmo letnica, and "Belvica" Acantholingua ohridana) and finally its diverse endemic bottom fauna (176 species; e.g. Ochridagammarus solidus), with particularly large endemism among crustaceans, molluscs, sponges and planarians.
 

     The lakeshore reed beds and wetlands provide critical habitat for hundreds of thousands of wintering water birds, including rare and threatened species such as the Dalmatian Pelican, Ferruginous Duck, Swan, Spotted Eagle, and Eastern Imperial Eagle.out you.​