Ibias River Nature · Ibias, Narcea, Asturias It rises at the Puerto de Cerredo, in the Cantabrian Mountains, and crosses the concejo of Ibias, to which it gives its name, from east to west, gathering the waters of the Forma, the Cervos and the Piliceiro before joining the Navia, of which it is the largest tributary, at the site of the Boadil bridge, on the Salime reservoir, already within the Lugo municipality of Negueira de Muñiz. Along its course it passes through Degaña, Cerredo, Taladrid, Cecos, San Antolín de Ibias and Marentes. Its basin structures a large part of the Fuentes del Narcea, Degaña e Ibias nature park, and marks strong contrasts in relief within the concejo, which ranges from 200 metres by the river to the 1,969 metres of Pico Miravales. Electrofishing surveys between 1997 and 2019 have detected the Duero nase (boga del Duero) in its waters. Photo: frankblacknoir (CC BY-SA 3.0) What to see and do in Ibias