Southern Brazil
The lagoon is partly brackish at its exit to the sea at Rio Grande do Sul, at Cassino. The ecoregion of the lagoon and its southern neighbour, the also large Lagoa Mirrim, includes a variety of aquatic habitats, including brackish-salt coastal lagoons, freshwater coastal lagoons, swamps, marshes, seasonal and permanent freshwater ponds, rivers, and streams. It contains a unique assemblage of species of the southern Atlantic coastal drainages.
