Fishes from the middle Cubatão River drainage São Paulo State , Brazil

This study aimed to survey the fish fauna of Cubatao River and its tributaries on the Atlantic Coast of Sao Paulo State, Brazil. For this study we captured the fishes in eight sampled sites: three in the Cubatao River itself (points 5, 6 and 7) and five in its tributaries, three on the left bank (1, 2 and 3) and two on the right bank (4 and 8) using an SAMUS 725M electric shock device, in a 50 meters area. Two samplings were done in rainy and dry season (2011). A total of six orders, nine families and 15 species, of which 53% were Siluriformes and 20% were Characiformes. The number of species collected in the middle Cubatao River basin represents 26.3% of the total richness recorded for coastal basins in the State of Sao Paulo (about 600 km of coastline).


Introduction
The Atlantic Forest, known in Brazil as "Mata Atlântica", originally covered 12% of Brazil, occurring along the eastern coast.Because of its location, it has been extensively exploited and displaced by growing urban centers or agricultural land use.Currently this biome is a cluster of forest patches in different successional stages, occupying a total area of less than 8% of the national territory and still subject to varying levels of disturbance (INPE 2014).According to Menezes et al. (2007) there are about 300 species of fishes found in the rivers and streams of the Atlantic Forest, with about 80% of them being endemic and 15% endangered, while the ecology and conservation status of many species are still unknown.
The Cubatão River is located along the "Serra do Mar", a mountain range that occurs along the Brazilian southern and southeastern coastline in the Atlantic Forest area, with its spring in the municipality of São Bernardo do Campo and its mouth feeding into the ocean near the municipality of Cubatão, both in São Paulo State.This river is of great socioeconomic importance to the city of Cubatão.It is an important source of water supply, receiving effluents from nearly all industries of Cubatão (Luiz-Silva et al. 2002), mainly of the chemical, petrochemical and fertilizer industries (CETESB 2001).The aim of this study was to inventory the species of fish in the middle section of the Cubatão River (area which is not affected by industry).

Study site
The inland waters of the State of São Paulo are concentrated in four watersheds: Alto Paraná, Paraíba do Sul, Ribeira de Iguape and a set of small drainages located in a narrow coastal belt that flows directly to the Atlantic Ocean and form a region denominated Coastal Drainages or Coastal Basins (Oyakawa and Menezes 2011).The climate Abstract: This study aimed to survey the fish fauna of Cubatão River and its tributaries on the Atlantic Coast of São Paulo State, Brazil.For this study we captured the fishes in eight sampled sites: three in the Cubatão River itself (points 5, 6 and 7) and five in its tributaries, three on the left bank (1, 2 and 3) and two on the right bank (4 and 8) using an SAMUS 725M electric shock device, in a 50 meters area.Two samplings were done in rainy and dry season (2011).A total of six orders, nine families and 15 species, of which 53% were Siluriformes and 20% were Characiformes.The number of species collected in the middle Cubatão River basin represents 26.3% of the total richness recorded for coastal basins in the State of São Paulo (about 600 km of coastline).(direct current, 650W, 12V, 99Hz, 8.0 λ, 12s), recording outputs for two dip nets with three passages in an area of 50 meters.
The specimens captured were anesthetized in a solution of benzocaine, fixed in 10% formalin and later transferred to 70% alcohol.The voucher specimens were deposited in Museu de Zoologia da Universidade de São Paulo.The species were identified according to Géry (1977) and Oyakawa et al. (2006) when necessary, compared with samples deposited in MZUSP.The species' nomenclature followed Reis et al. (2003) and Eschmeyer (2013).

Results
We collected a total 1,598 specimens belonging to six orders, nine families and 15 species, of which 53% were Siluriformes and 20% were Characiformes (Table 2).The most representative families were Loricariidae, Characidae and Heptapteridae, both with three species each (20%).The other orders were represented by one family each (Figure 2).
Phalloceros reisi was the most frequent species among the streams studied, occurring in all locations.Rhamdioglanis frenatus and Hollandichthys multifasciatus occurred in four sites and Acentronichthys leptos in three sites (Figure 2).Geophagus brasiliensis and Rineloricaria sp. were the only species that occurred in only one site (Cubatão River) (Table 2).
In the Coastal Basin region of São Paulo state, Oyakawa and Menezes (2010) reported 57 species, of which 15 were found in this study, being the equivalent of a 26.3% of the total of that basin.
In Jurubatuba River, the study by Mattox and Iglesias (2010) of these were found in both surveys (Hollandichthys multifasciatus, Schizolecis guntheri, Acentronichthys leptos, Rhamdia quelen, Gymnotus pantherinus, Synbranchus marmoratus and Geophagus brasiliensis).The Cubatão River showed greater richness in the Family Loricariidae with three species.The Jurubatuba River had greater richness within the order Cyprinodontiformes, with six species.The genus Phalloceros, was the only one of this order to occur in both studies.These results perhaps demonstrate the high selectivity of environments by the species of the Atlantic Forest (Menezes et al. 2007).
The absence of Hollandichthys multifasciatus in the main river (Cubatão) may be associated with the species preference of vegetation cover (Bertaco and Malabarba, 2013), as it has insectivore eating habits and predominantly consumes allochthonous material (Sabino and Castro 1990).On the other hand, Rineloricaria sp. and Geophagus brasiliensis occurred only in sites located in the main river.Rineloricaria sp. is a species associated with sites with higher current (Reis and Cardoso 2001).However, according to Sarmento-Soares et al. (2007) G. brasiliensis is an opportunistic species adaptable to intense solar incidence.Opportunistic species tend to have higher trophic plasticity, suggesting that low-order rivers, exhibit low variability in food supply, thus resulting in the absence of G. brasiliensis in these environments (Knoppel 1970).
Additional samples, mainly in the headwaters of Cubatão river, a still unexplored region, are necessary to better represent the richness of the local fish fauna.Although this study contributes to knowledge of Cubatão River fish, new studies should be performed to diagnose anthropogenic changes, as accidents with chemical spills on roads that border the river and give access to the largest port in Latin America, in order to produce a more complete and consistent diagnosis because the species may be subject to temporal changes.

Figure 1 .
Figure 1.Map showing the sampling sites in the middle Cubatão River drainage.

Table 1 .
, there were 19 freshwater species captured belonging to the same orders of middle Cubatão.Seven Geographical coordinates of the sampled sites.Datum: WGS 84.