Sali River.Pmd

View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by SEDICI - Repositorio de la UNLP Ichthyol. Explor. Freshwaters, Vol.1, No 3, pp 269-276, 1 fig., 3 tabs., July 1990 © 1990 by Verlag Dr. Friedrich Pfeil, München, FRG - ISSN 0936-9902 269 Ichthyological and limnological observations on the Sali river basin (Tucuman, Argentina) Amalia Maria Miquelarena *, Roberto C. Menni **, Hugo L. Lopez and Jorge R. Casciotta * The ichthyofauna of the Sali river basin, Tucuman, Central Argentina is analyzed. Twenty three species and two subspecies were collected, of which nine species and one subspecies are new for the Sali river basin: Cheirodon interruptus, Odontostilbe microcephala, Cyphocharax cf. modestus, Jobertina rachowi, Pimelodus albicans, Trichomycterus alterum, Corydoras paleatus, Jenynsia lineata alternimaculata, Bujurquina vittata and Cichlasoma portalegrense. This represents a 37% increase in the known diversity of the Sali river fish fauna. The Paranensean composition of this fauna lends support for a western extension of the Parano-platense zoogeographic province. The hypothesis is advanced that the lack of tributaries and therefore the lack of environments of creek type in the Dulce river explains the observed impoverishment in the number of species compared with the Sali. Physicochemical data obtained at ten localities show that the mean pH is higher in the Sali river than in the upper Parana and Paraguay rivers, but is nearly the same as that in Cordoba environments. Total dissolved solids are less than in Pampean lakes or Cordoba creeks. At all localities in the Sali - 2+ + river C03 H , Ca and Na were the most abundant ions. Introduction (1984) provide a complete list of the ichthyo- Many authors (Lachner et al., 1976; Margalef, fauna from the highlands in Cordoba and San 1983; Lowe-McConnell, 1987) have mentioned Luis provinces, including a faunal comparison the need for research relating to the faunistic among several basins and limnological obser- composition and ecology of South American vations of sampled streams in eleven basins. fresh water environments. Bohlke et al. (1978) Casciotta et al. (1989) report the first fish fauna emphasized the need for studies of the known from the Salado river in Santiago del ichthyofauna in many areas, and for collecting Estero province, as well as new species from in many regions before fish become rare or the Dulce river, and also discuss the limnology disappear. of the Salado basin. In spite of a considerable amount of research The Sali river basin (Fig. 1) includes Tucuman done on Argentine fishes during the last province and parts of Salta and Catamarca twenty years (see Lopez et al., 1981, 1982, 1987) provinces. Its main tributaries arise in the an extensive area of central Argentina has only Calchaquies and Aconquija highlands. The been studied in recent years. Menni et al. river is called Tala until its confluence with the * Instituto de Limnologia de La Plata, 51 N° 484, 1900 La Plata, Argentina ** Museo de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina Miquelarena et al.: Sali river basin 270 Material and methods Most of the material was collected by the authors during two trips to the Sali river basin in May 1980 and April 1983 and deposited in the ichthyological collection of the Museo de La Plata (MLP). Additional material was obtained from Mrs. Butti de Lozano, from the Museo de La Plata and from the Instituto Miguel Lillo, Tucuman (IML). When no collector is mentioned, the material was gathered by RCM, HLL and JRC. Detail of localities is listed in the Appendix, together with the material examined. The sampled environments are mountain creeks, rivers with rocky bottom and transparent waters, and plain creeks and rivers. In rivers with large flow, the banks or marginal environments were sampled. Sampling was made with a beach seine 15 m wide with a 10 mm mesh, hand nets and the ichthyocide Pronoxfish. The systematic arrangement used in Tables 1 and 2 mainly follows Greenwood et al. (1966), but Géry (1977) is used within the Characoidei. For the comparison of different sections of the river, Long’s (1963) index was used (see Matson, 1976 and Menni et al., 1984). For the obtention of physicochemical parameters, one liter water samples fixed with chloroform were taken at the collecting place just before fishing. The analysis Fig. 1. Localities sampled in the Sali river basin. Num-bers as were made by the Laboratory of Chemistry of the in Appendix. La Plata Institute of Limnology according to APHA (1971) methods. Candelaria. With the name Sali it crosses through 250 km of Tucuman province. In Santiago del Estero province it is named the Dulce river Results (Mazza, 1961; see Casciotta et al., 1989). The composition of the fish fauna from the Dulce In this paper we report the composition of the Sali and Sali rivers is shown in Table 1. The table has river basin ichthyofauna, compare the composition been composed with data from Ringuelet (1975) of the fish fauna in different sections of the Sali- on the Sali river basin, those provided by Casciotta Dulce river system and discuss the distribution of et al. (1989) on both rivers, and our own data on species. Water physicochemical characteristics are the Sali river. Table 2 shows the species gathered compared with those from other Argentinian by the authors from the Sali river basin envi- basins. The information is analyzed within the ronments, detailing new records for the basin zoogeographic framework provided by Ringuelet and presence of species in each locality. Table 3 (1961, 1975) and Arratia et al. (1983). includes the physicochemical data of the water. Ichthyol. Explor. Freshwaters, Vol.1, No 3 271 Discussion These data show that the Dulce river is some- what poorer than the Sali. The similarity value Distributional and ecological conclusions. In a obtained applying Long’s index is 44.8%. It zoogeographical sense, the Sali basin fish fauna seems too low for sections of the same river. An belongs in the Paranensean dominion of the explanation of this difference is suggested below: Subtropical province (Ringuelet, 1961, 1975). Ringuelet (1975) reports from the Sali river basin The Sali river samples have been collected mainly twenty six species and an undetermined species in tributary creeks, presumptively stable and not of Trichomycterus, to which Loricaria tucumanensis disturbed by human action, which constitute described by Isbrücker (1981) must be added. marginal environments different from the main course. In the Dulce river basin, sampling has been We have found thirteen species already reported made in artificial or altered locations, due to the by Ringuelet. Besides, we have captured nine absence of such tributaries or other small envi- species and a subspecies which are new reports ronments related to the river. We suggest that the for the basin, namely Cheirodon interruptus, Odon- above diversity pattern reflects the amount and tostilbe microcephala, Cyphocharax cf. modestus, quality of habitats available in each section, not Jobertina rachowi, Pimelodus albicans, Tricho- only for sampling but for the organisms as well. mycterus alterum, Corydoras paleatus, Jenynsia Supporting this interpretation, Mazza (1961) lineata alternimaculata, Bujurquina vittata and mentions that the Sali basin in Tucuman is formed Cichlasoma portalegrense (Table 2). This represents by tributaries from the Calchaqui and Aconquija an increase of 37% for the Sali river basin and highlands, whereas the Dulce river in plain region hence for the Tucuman province. These fishes in Santiago del Estero receives almost no tributary. are typically Paranensean species; T. alterum being the only Andean species. Ringuelet (1975) Considering Table 1 in this ecological context and comments that «With the exception of the Ringuelet’s (1975) opinion quoted above, the absence trichomycterids and some species, as Rinelori- in the Dulce river of three species of Trichomycterus caria catamarcensis, which do not live in the must be noted. They are usually living in fast current Paranensean territory, all the ichthyofauna from and well oxygenated waters in Subandean envi- Tucuman rivers is composed by the same species ronments but are lacking in the Dulce basin. that could be found in any place of the Sub- tropical pampasia» and that «There are ecotonal Faunal conclusions. Lopez et al. (1984) mention sympatry among highlands (or Andean) and that it was certain that new searches in Argentina Paranensean forms, with a clear dominance of would increase the known distribution of many the latter» (in the studied area). This situation groups, an assumption confirmed by the new does not change with the new reports which have extensions of distribution found during the last low percentage (1 sp. = 10%) of Andean forms. years (Lopez et al., 1980; Miquelarena et al., 1981; Lopez et al., 1984 and Menni et al., 1984). The The Sali and Dulce rivers are physically divided more than 35 % increase of fish species for the by the Rio Hondo dam, which forms a lake of Sali basin based on the present small collection 330 km2. Data from Casciotta et al. (1989) and supports this conclusion. those gathered for this paper show the following number of species. For the Sali river 28 species were Distributional novelties can be summarized as known. Twenty five were obtained by us, of which follow: 10 are new reports for the basin. Total number of species for the Sali river is 38 species (the introduced Cheirodon interruptus was found at the Cadillal Gambusia affinis is not considered). dam and in Calimayo creek. This species has been Twenty one species were known for the Dulce river. reported from the lower Uruguay, La Plata and We have collected 17, of which 6 are new reports. lower Parana rivers, from Tala in Salta (Ringuelet Total number of species for the Dulce river is 27.

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