Rio Pelotas is a significant river in southern Brazil, originating on the western slope of the Serra Geral at Alto do Bispo in Santa Catarina state — remarkably close to the Atlantic coast, just about 64 kilometers away. From its headwaters, the river arches northwestward across the uplands for approximately 450 kilometers before joining the Canoas River near Marcelino Ramos to form the Uruguay River. Throughout much of its course, the Rio Pelotas forms the natural border between Santa Catarina and Rio Grande do Sul states. The river is impounded at two major points — the Machadinho Dam and the Barra Grande Dam — which significantly shape the character of the river in their respective reaches. With a total length of roughly 276 miles, the Rio Pelotas is a diverse and productive fishery, supporting an impressive array of native fish species across its varied habitats, from fast-moving upland channels to the deeper, slower waters of its reservoirs.