In 2015, the Lake Tana region was nominated as a UNESCO Biosphere Reserve recognizing its national and international natural and cultural importance.

[4] Lake Tana was formed by volcanic activity, blocking the course of inflowing rivers in the early Pleistocene epoch, about 5 million years ago.

"[6] When James Bruce visited the area in 1771, he noted that the locals counted 45 inhabited islands, but stated he believed that "the number may be about eleven.

"[6] Anton Stecker, in 1881, made a detailed examination of the lake, enabling substantially accurate maps,[1] and counted 44 islands.

[6] Remains of ancient Ethiopian emperors and treasures of the Ethiopian Church are kept in the isolated island monasteries (including Kebran Gabriel, Ura Kidane Mehret, Narga Selassie, Daga Estifanos, Medhane Alem of Rema, Kota Maryam, and Mertola Maryam).

They include the fourteenth-century Debre Maryam, and the eighteenth-century Narga Selassie, Tana Qirqos (said to have housed the Ark of the Covenant before it was moved to Axum), and Ura Kidane Mehret, known for its regalia.

The remaining non-endemic species are Nile tilapia (widespread in Africa, but with the endemic subspecies tana in the lake), E. humilis, G. dembecha, G. dembeensis and the large African sharptooth catfish.

[9][10] Lake Tana supports a large fishing industry, mainly based on the Labeobarbus barbs, Nile tilapia and sharptooth catfish.

[14] In the early 2000s, the local government for the first time introduced a fisheries legislation and it is hoped this will have a positive effect on the fish populations.

Bahir Dar has become a large city and it is rapidly growing; its wastewater is generally released directly into the lake.

A potentially serious threat to the unique ecosystem would be an introduction of a large and efficient predatory species like the Nile perch, which has been implicated in numerous extinctions in Lake Victoria.