The site is a former marine inlet now separated from the sea by a narrow sand-spit. The lake is predominantly freshwater with a maximum depth of 18 m. The western shore is formed by a steep limestone promontory, and narrow reedbeds (Phragmites) occur. In winter up to 90% of the lake area may freeze.
This is an important site for passage waterbirds, particularly Anatidae and Laridae; the surrounds are a stop-over site for migrating passerines. Species of global conservation concern that do not meet IBA criteria: Aythya nyroca (2-40 passage birds).
BirdLife International (2020) Important Bird Areas factsheet: Lake Siutghiol. Downloaded from http://www.birdlife.org on 28/10/2020.