The lagoon is located next to the beach Mexilloeira and isolated from the sea by a large dune. Rushes limit the lagoon to shelter migratory birds that inhabit this place. It is the only lake with these characteristics in the province of Pontevedra.

This cove is declared Wetland of International Importance and included in the RANSAR agreement.

It is located between the peninsula of O Grove, A Lanzada isthmus and the southwest of the Arousa estuary, covering the estuary of the Umia to Cambados. Here were the salt mines that gave the region its name: O Salnés.

The entrance and exit of the water is through the small canal that forms the island of La Toja. Shallow water and little movement forms a chosen by a variety of birds wintering or resting on their long migrations ecosystem.

It highlights the natural area of ​​the cove of O Bao, where we can see species such as Grey Heron, curlews, mallards, Correlimos ... among many others.