Baía Sul is a substantial coastal bay covering approximately 250 square kilometers, separating Santa Catarina Island from the mainland of southern Brazil. This expansive, sheltered body of saltwater features a complex shoreline with numerous inlets, coves, and estuarine environments where rivers from both the island and the continent flow into the bay. The bay's geography creates a mix of shallow environments, deeper channels, and protected areas that support a diverse marine ecosystem, making it a significant destination for both recreational and artisanal fishing.