Comunidades de peces en desembocaduras de ríos y esteros de la Región de Valparaíso, Chile central

abstract the fish community in 11 rivers mouths and estuaries in the region of valparaiso, was studied between 1999 and 2006. the fish collection was carried out through electro fishing. the conservation status and origin of species was determined. the results showed the presence of 23 species representing 10 orders, 14 families and 18 genera. fourteen species (68.8%) were found to be native and/or endemic, of which, 12 have conservation problems; basilichthys microlepidotus is considered endangered, nine are vulnerable and two as inadequately known. in general, introduced species were the most abundant, including cnesterodon decemmaculatus and cheirodon interruptus which accounted for 62.7% of all fish collected, followed by the chilean silverside with 15.6% while 20 other species had a low representation, as it happened with the endemic species mordacia lapicida, trichomycterus areolatus, basilichthy australis and percilia gillisi. this information will allow to recognize in a better way the effects of the activities to be developed in these ecosystems.