The site comprises a shallow bay, largely cut off from the sea apart from at three places. As a result the water is brackish. The water is nutrient-rich from rivers flowing into the lagoon.
The site regularly holds 20,000 or more waterbirds in winter.
BirdLife International (2020) Important Bird Areas factsheet: Usedom lagoon (Peenestrom, Achterwasser, Kleines Haff with Neuwarper See). Downloaded from http://www.birdlife.org on 09/08/2020.