Gasterópodos planctónicos (Pterópodos y Heterópodos) como bioindicadores de los eventos "El Niño" 1992 y 1997 - 1998 en la estación fija "La Libertad", Ecuador
Con este aporte al mejor conocimiento de los Pterópodos y Heterópodos, el INOCAR cumple con una recomendación de la Comisión Permanente del Pacífico Sur (CPPS) de estudiar los organismos bioindicadores con la finalidad de encontrar en un futuro, especies que se puedan utilizar como Biondicadores tempranos del Evento "El Niño".From the analysis of 135 zooplankton surface samples, obtained each 15 days since june/90 to mayo/98 at the station "La Libertad", the position is 10 miles off shore the coast of Santa Elena Peninsula, Ecuador. 15 planktonic gastropds were identified, of which 10 are Pteropods and 5 are Heteropods. From the 15 species founded, 9 are considered about good biological indicators of the marine ecosystem, including anomalous or unstable conditions and the warm event "El Niño", they are the following:Hyalocylis striata, Limacina trochiformis, Creseis virgula, Creseis acicula, Desmopterus papilio, Atlanta peroni, Atlanta lesueuri, Atlanta gaudichaudi y Atlanta turriculata. The 6 specie that have been showed few abundance and no allway respond to the variations of the marine ecosystem near the coast of Ecuador, they are: Firoloida desmaresti, Cavolinia uncinata, Cavolinia longirostris, Diacria quadridentata, Limacina bulimoides y Clio pyramidata. With the intention to know better the marine environment variation of each year since june/90 to mayo98, in this paper an analysis of the presence and relative abundance of the Pteropods and Heteropods founded is presented. These percentage and the different marine environment condition are relationed and are included "normal" and "anomalous or unstable" condition and the warm event "El Niño". For a better knowledment of each one species in the marine ecosystem of the ecuadorian coast, and abstract appreciation of the marine environment relation and the total and relative abundances, development of the organisms and the shell, is presented, and when forming association the different populations. For a better observation of the change on the total abundance of each one species, two tables and five figures are presented, where show the variation of the relations between the species and the "normal" or "anomalous" in the marine environment 10 miles off shore the ecuadorian coast.