The Paraíba do Sul (Portuguese pronunciation:[ˈʁiupɐɾɐˈibɐduˈsuw]), or simply termed Paraíba, is a riverinsoutheast Brazil. It flows 1,137 km (706 mi)[1] west to northeast from its farthest source at the source of the river Paraitinga to the sea near Campos dos Goytacazes. The river receives its name when it meets the river Paraibuna at the Paraibuna dam.
The valley of the Paraíba do Sul ranges from the latitudes 20°26' and 23°39'S and the longitudes of 41° and 46°30'W and covers an area of about 57,000 km2 (22,000 sq mi) distributed over three states. The main economic activities are industry and cattle raising.
Presently only two parts of the river can be navigated:
The lower section, between the mouth and São Fidélis, about 90 km. It has a declivity of 22 cm/km. There is incipient navigation carried out by small boats that transport mainly construction material to the city of Campos dos Goytacazes.
The upper middle section, between Cachoeira Paulista and Guararema, about 280 km (170 mi). Despite the small declivity of 19 cm/km, navigation is restricted to tourist boats.
Elsewhere navigation is hampered by various obstacles; waterfalls, rapids, sections with great declivity and various hydroelectric works with no locks.
Other factors impeding navigation are the existence of highway and railway bridges, the proximity of roads and railways following the riverbank and the location of several cities on its banks.
Unlike rivers in northern Brazil where seasonal variations in water temperature generally are relatively limited, those in southern Brazil, such as Paraíba do Sul, exhibit distinct differences between winter and summer. During a survey of the river in Lorena, São Paulo, the water varied from 26.6 °C (79.9 °F) in the summer to 15.2 °C (59.4 °F) in the winter.[2] The pH is neutral and generally fluctuates between 6 and 8.[2][3][4]
The Paraíba do Sul basin is home to just above 100 native fish species with most in the families Loricariidae, Characidae and Trichomycteridae.[5] About 40% of the fish species in the river basin are endemic (the genus Oligobrycon is entirely restricted to the basin)[5] and new species have been discovered in recent years, including the small catfish Pareiorhina hyptiorhachis that only was scientifically described in 2013.[6]
As a consequence of flowing through one of the most densely populated and industrialised parts of Brazil, the Paraíba do Sul suffers from pollution.[7][8][9] Studies of the native cichlid Geophagus brasiliensis have found that levels of some heavy metals exceed the limits set by the Brazilian Food Legislation.[8] Other threats are dams and the approximately 70 introduced species,[9][10] including 46 species of non-native fish[11] and the parasitic copepod Lernaea cyprinacea.[12] Several native species (e.g., Brycon insignis,[13]Pogonopoma parahybae[11] and Steindachneridion parahybae[14]) are seriously threatened, and a general fall in abundance and species richness has been observed.[8] Some, such as the endemic Hypostomus auroguttatus, have successfully adapted to the changes.[15] The catfish Potamarius grandoculis is only known from the vicinity of the mouth of the Paraíba do Sul and Doce Rivers, but it may already be extinct.[16]
^Pinto, B.C.T.; Peixoto, M.G.; and Araújo, F.G. (2006). Effects of the proximity from an industrial plant on fish assemblages in the rio Paraíba do Sul, southeastern Brazil. Neotrop. Ichthyol. 4(2): 269-278.
^Silva, L.B.C. (2008). Avaliação espaço-temporal de metais pesados no rio paraíba do sul e rio imbé por meio de plantas de eichhornia crassipes (mart.) solms (aguapé), séston e sedimento. Masters Thesis. UENF/Ecologia e Recursos Naturais, Rio de Janeiro.
^Silva, G.C.; Roxo, F.; and Oliveira, C. (2013). Pareiorhina hyptiorhachis, a new catfish species from Rio Paraíba do Sul basin, southeastern Brazil (Siluriformes, Loricariidae). ZooKeys 315: 65-76.
^Pinto, B.C.T; Peixoto, M.G.; and Araújo, F.G. (2006). Effects of the proximity from an industrial plant on fish assemblages in the rio Paraíba do Sul, southeastern Brazil. Neotropical Ichthyology 4(2).
^ abcCalza, C.; Anjosa, M.J.; Castroa, C.R.F.; Barrosob, R.C.; Araujoc, F.G.; and Lopesa, R.T. (2004). Evaluation of heavy metals levels in the Paraíba do Sul River by SRTXRF in muscle, gonads and gills of Geophagus brasiliensis. Radiation Physics and Chemistry 71: 787–788.
^Magalhães, A.L.B. (2006). First record of lernaeosis in a native fish species from a natural environment in Minas Gerais state, Brazil. Pan-American Journal of Aquatic Sciences 1(1): 8-10
^Gomes, I.D.; Araújo, F.G.; Nascimento, A.A.; and Sales, A. (March 2014). Equilibrium reproductive strategy of the armored catfish Hypostomus auroguttatus (Siluriformes, Loricariidae) in a tropical river in Southeastern Brazil. Environmental Biology of Fishes.
