Pseudoplatystoma corruscans, known as surubim or peixe rei locally, is a scale-less fish with three pairs of large sensory barbels near the nostrils. This species has a long, cylindrical greyish body with black spots that look painted on, and a white back. The head is large and flat. This species lives at the bottom of freshwater rivers, lakes and ponds. The largest size of an individual recorded was 182 cm in length.
The riverside communities, for whom artisanal fishing is the main source of household income, were established and developed on the basis of the native fish of the São Francisco River. Fishermen usually fish alone or in pairs. When fishing alone a hook is always used, and when fishing in pairs a boat is used with a net. Profit sharing is arranged in various ways, depending largely on each occasion and the rules established by the fishermen. Today, in the area of Remanso, fishermen’s associations involve about 150 families.
The São Francisco River is historically one of the main fisheries in Brazil, providing fish for its riverside population and meeting market demand in northeast and southeast Brazil. The fauna of the São Francisco River includes countless species of fish, but the river’s fish stocks, like in other bodies of water, are in decline because of increased pressure from fishing.
The São Francisco River is 2,700 km long and its source is in Serra da Canastra, in the state of Minas Gerais. It flows from south to north through Bahia and Pernambuco, where it changes course southeast, flowing into the Atlantic Ocean between Alagoas and Sergipe. Because of its size and the different environments it flows through, the Hydrographic Region is divided into four sections: Alto São Francisco, Médio São Francisco, Sub-Médio São Francisco, and Baixo São Francisco. The Hydrographic Region of the São Francisco River comprises parts of the Atlantic Forest, Cerrado, Caatinga and Coastal and Insular biomes.
In the past, fishing powered the economy of riverside towns and cities in the São Francisco region in Bahia, but with the degradation of the environment, this activity is losing ground every day, and it is also competing with Cichla and tilapia farming. Other factors potentially leading to extinction of the species in the region: The construction of large dams along the São Francisco River, such as the Três Marias dam in Minas Gerais and Sobradinho dam in Bahia, has hindered the reproductive migration of the fish and markedly restricted the filling of reservoirs downstream, reducing the fill level of adjoining lakes, which serve as nurseries for dozens of these species.
As a result, there has been a major decline in fish stocks, as well as a reduction in the biodiversity of fish species in the hydrographic basin, leading to ne near disappearance of the surubim. According to artisanal fishermen, other threats to this fish are: the lack of monitoring of illegal fishing during the fish’s reproduction period; the lack of control of fishing carried out by other states in the northeast; the lack of compliance with the number of nets deployed for fishing; and the lack of awareness about preservation of local biodiversity, both among fishermen and municipal authorities.