POPULATION DISTRIBUTION AND ABUNDANCE OF ENDEMIC FISH IN THE RIOVERDE PLAIN, S.L.P., MÉXICO

Abstract

In the Rioverde plain, San Luis Potosí, México, there are wetlands distributed in five natural spring systems, in addition to the green river itself, with endemic fishes. A study was developed to locate new reservoirs for endemic fish, in addition to confirming the presence of each species, estimating their abundance and possible threats. The localization of reservoirs was done through a visual analysis in ArcGIS 9.2, of the panchromatic band of the SPOT satellite. The presence and abundance of species was determined through direct observation while diving. The records showed 14 species of fish, of which five are endemic to the plain, two more to the region, two are native but not endemic, and five introduced. The endemic fish, Tampichthys mandibularis and Ataeniobius toweri, showed greater distribution with high abundance in some systems, and medium to scarce in others. The species Cualac tessellatus was not found in system one or in the Río Verde, although in the others it was abundant. Herichthys labridens and H. bartoni were found in all the systems, except the Río Verde; the first was abundant and the second scarce. Poecilia mexicana is distributed broadly and abundantly, while Gambusia panuco and P. latipunctata were only found in system four. T. dichromus was found in system five with medium abundance. Astyanax mexicanus and Oreochromis sp. were found in all the systems and were the only species in the Río Verde. The presence of Ictalurus mexicanus was confirmed in systems three and four, and I. furcatus in the latter. Endemic species were confirmed in three new systems of natural springs (1, 2 and 3), mitigating the risk of extinction. Studies about distribution, possible threats and management plans that guarantee viability in the long-term of the species and their habitats are necessary.