Variación de la población del ictioplancton en el Pacífico Sur Oriental durante diciembre de 1997

Abstract

Uno de los principales objetivos de esta investigación es contribuir al estudio del ictioplancton y zooplancton durante el evento El Niño 1997 en el Pacífico Sur Oriental y a la vez relacionar la abundancia, migración y distribución de los diferentes grupos de organismos con los parámetros de temperatura y salinidad, con respecto a la variación de la población del ictioplancton

In the initial part of the VII antarctic expedition, between Guayaquil-Valparaíso, on board vessel B/I Orion of ecuadorian navy in december 1998, zooplankton samples were collected through horizontal and oblique drags using nets bongo 500µm. The purpose of the later analysis was to determine the ichthyoplankton population in the South Eastern Pacific. No stations were done in peruvian water.Total amount of 6380 eggs (10m²)-1 and 2173 larvas (10m²)-1 were estimated from the analysis. The fish eggs belonging to 8 orders, 13 families and 1 genera, while 7 orders, 14 families and 20 genera of fish larvae were registered. The highest concentration of fish eggs was registered in tropical superficial waters masses (ATS), suntropical superficial (ASS) and coastal peruvian waters (ACP). The fish larvae were more abundant in chileans coastal waters, where equatorial subsuperficial water masses (AESS), subtropical subsuperficial (ASS), subantarctic (ASA) and peruvian coastal (ACP) waters found Sardinops sagax y Thunnus sp., larvae were recorded in the south west of Gulf of Guayaquil. There were also identification of two species related with tropical waters, de Benthosema panamense y Myctophum sp. The most representative families in the study ares were Bathylagidae, Gonostomatidae, Scombridae y Myctophidae with the genera Diogenichthys sp., Gonichthys laternatun, Gonichthys sp, Lampanycthus sp., related with tropical species from the west. The presence, migration and distribution of the ichthyoplankton suggest a direct relationship with the temperature of the study area. The temperature and salinity have directly influenced the showing up and distribution of the ichthyoplankton, showed a migration to the North of Chile that coincided with the temperature decreasing.