Sea mammals
Three different species of seals are recorded in the waters of the Baltic Sea along the Polish coast: the grey seal, the harbor seal and the ringed seal. The grey seal is the most common at the Polish coast. The other two species of seals are mainly connected with the northern part of the Baltic Sea, and are occasionally seen at the Polish coast. Furthermore, the only species of cetacean permanently living in the Baltic Sea is the harbor porpoise, today, unfortunately, critically endangered.